diff --git a/library/entropy.c b/library/entropy.c
index 52b98cd..e17512e 100644
--- a/library/entropy.c
+++ b/library/entropy.c
@@ -68,16 +68,18 @@
 
 void mbedtls_entropy_init( mbedtls_entropy_context *ctx )
 {
-    memset( ctx, 0, sizeof(mbedtls_entropy_context) );
+    ctx->source_count = 0;
+    memset( ctx->source, 0, sizeof( ctx->source ) );
 
 #if defined(MBEDTLS_THREADING_C)
     mbedtls_mutex_init( &ctx->mutex );
 #endif
 
+    ctx->accumulator_started = 0;
 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
-    mbedtls_sha512_starts( &ctx->accumulator, 0 );
+    mbedtls_sha512_init( &ctx->accumulator );
 #else
-    mbedtls_sha256_starts( &ctx->accumulator, 0 );
+    mbedtls_sha256_init( &ctx->accumulator );
 #endif
 #if defined(MBEDTLS_HAVEGE_C)
     mbedtls_havege_init( &ctx->havege_data );
@@ -116,6 +118,7 @@
     mbedtls_entropy_add_source( ctx, mbedtls_nv_seed_poll, NULL,
                                 MBEDTLS_ENTROPY_BLOCK_SIZE,
                                 MBEDTLS_ENTROPY_SOURCE_STRONG );
+    ctx->initial_entropy_run = 0;
 #endif
 #endif /* MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES */
 }
@@ -128,7 +131,17 @@
 #if defined(MBEDTLS_THREADING_C)
     mbedtls_mutex_free( &ctx->mutex );
 #endif
-    mbedtls_zeroize( ctx, sizeof( mbedtls_entropy_context ) );
+#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
+    mbedtls_sha512_free( &ctx->accumulator );
+#else
+    mbedtls_sha256_free( &ctx->accumulator );
+#endif
+#if defined(MBEDTLS_ENTROPY_NV_SEED)
+    ctx->initial_entropy_run = 0;
+#endif
+    ctx->source_count = 0;
+    mbedtls_zeroize( ctx->source, sizeof( ctx->source ) );
+    ctx->accumulator_started = 0;
 }
 
 int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx,
@@ -175,13 +188,16 @@
     unsigned char tmp[MBEDTLS_ENTROPY_BLOCK_SIZE];
     size_t use_len = len;
     const unsigned char *p = data;
+    int ret = 0;
 
     if( use_len > MBEDTLS_ENTROPY_BLOCK_SIZE )
     {
 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
-        mbedtls_sha512( data, len, tmp, 0 );
+        if( ( ret = mbedtls_sha512_ret( data, len, tmp, 0 ) ) != 0 )
+            goto cleanup;
 #else
-        mbedtls_sha256( data, len, tmp, 0 );
+        if( ( ret = mbedtls_sha256_ret( data, len, tmp, 0 ) ) != 0 )
+            goto cleanup;
 #endif
         p = tmp;
         use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
@@ -190,17 +206,35 @@
     header[0] = source_id;
     header[1] = use_len & 0xFF;
 
+    /*
+     * Start the accumulator if this has not already happened. Note that
+     * it is sufficient to start the accumulator here only because all calls to
+     * gather entropy eventually execute this code.
+     */
 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
-    mbedtls_sha512_update( &ctx->accumulator, header, 2 );
-    mbedtls_sha512_update( &ctx->accumulator, p, use_len );
+    if( ctx->accumulator_started == 0 &&
+        ( ret = mbedtls_sha512_starts_ret( &ctx->accumulator, 0 ) ) != 0 )
+        goto cleanup;
+    else
+        ctx->accumulator_started = 1;
+    if( ( ret = mbedtls_sha512_update_ret( &ctx->accumulator, header, 2 ) ) != 0 )
+        goto cleanup;
+    ret = mbedtls_sha512_update_ret( &ctx->accumulator, p, use_len );
 #else
-    mbedtls_sha256_update( &ctx->accumulator, header, 2 );
-    mbedtls_sha256_update( &ctx->accumulator, p, use_len );
+    if( ctx->accumulator_started == 0 &&
+        ( ret = mbedtls_sha256_starts_ret( &ctx->accumulator, 0 ) ) != 0 )
+        goto cleanup;
+    else
+        ctx->accumulator_started = 1;
+    if( ( ret = mbedtls_sha256_update_ret( &ctx->accumulator, header, 2 ) ) != 0 )
+        goto cleanup;
+    ret = mbedtls_sha256_update_ret( &ctx->accumulator, p, use_len );
 #endif
 
+cleanup:
     mbedtls_zeroize( tmp, sizeof( tmp ) );
 
-    return( 0 );
+    return( ret );
 }
 
 int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx,
@@ -255,7 +289,9 @@
          */
         if( olen > 0 )
         {
-            entropy_update( ctx, (unsigned char) i, buf, olen );
+            if( ( ret = entropy_update( ctx, (unsigned char) i,
+                                        buf, olen ) ) != 0 )
+                return( ret );
             ctx->source[i].size += olen;
         }
     }
@@ -341,33 +377,52 @@
     memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
 
 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
-    mbedtls_sha512_finish( &ctx->accumulator, buf );
+    /*
+     * Note that at this stage it is assumed that the accumulator was started
+     * in a previous call to entropy_update(). If this is not guaranteed, the
+     * code below will fail.
+     */
+    if( ( ret = mbedtls_sha512_finish_ret( &ctx->accumulator, buf ) ) != 0 )
+        goto exit;
 
     /*
      * Reset accumulator and counters and recycle existing entropy
      */
-    memset( &ctx->accumulator, 0, sizeof( mbedtls_sha512_context ) );
-    mbedtls_sha512_starts( &ctx->accumulator, 0 );
-    mbedtls_sha512_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
+    mbedtls_sha512_free( &ctx->accumulator );
+    mbedtls_sha512_init( &ctx->accumulator );
+    if( ( ret = mbedtls_sha512_starts_ret( &ctx->accumulator, 0 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_sha512_update_ret( &ctx->accumulator, buf,
+                                           MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 )
+        goto exit;
 
     /*
      * Perform second SHA-512 on entropy
      */
-    mbedtls_sha512( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
+    if( ( ret = mbedtls_sha512_ret( buf, MBEDTLS_ENTROPY_BLOCK_SIZE,
+                                    buf, 0 ) ) != 0 )
+        goto exit;
 #else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
-    mbedtls_sha256_finish( &ctx->accumulator, buf );
+    if( ( ret = mbedtls_sha256_finish_ret( &ctx->accumulator, buf ) ) != 0 )
+        goto exit;
 
     /*
      * Reset accumulator and counters and recycle existing entropy
      */
-    memset( &ctx->accumulator, 0, sizeof( mbedtls_sha256_context ) );
-    mbedtls_sha256_starts( &ctx->accumulator, 0 );
-    mbedtls_sha256_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
+    mbedtls_sha256_free( &ctx->accumulator );
+    mbedtls_sha256_init( &ctx->accumulator );
+    if( ( ret = mbedtls_sha256_starts_ret( &ctx->accumulator, 0 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_sha256_update_ret( &ctx->accumulator, buf,
+                                           MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 )
+        goto exit;
 
     /*
      * Perform second SHA-256 on entropy
      */
-    mbedtls_sha256( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
+    if( ( ret = mbedtls_sha256_ret( buf, MBEDTLS_ENTROPY_BLOCK_SIZE,
+                                    buf, 0 ) ) != 0 )
+        goto exit;
 #endif /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
 
     for( i = 0; i < ctx->source_count; i++ )
diff --git a/library/error.c b/library/error.c
index 151ca4e..9079c5c 100644
--- a/library/error.c
+++ b/library/error.c
@@ -101,6 +101,18 @@
 #include "mbedtls/md.h"
 #endif
 
+#if defined(MBEDTLS_MD2_C)
+#include "mbedtls/md2.h"
+#endif
+
+#if defined(MBEDTLS_MD4_C)
+#include "mbedtls/md4.h"
+#endif
+
+#if defined(MBEDTLS_MD5_C)
+#include "mbedtls/md5.h"
+#endif
+
 #if defined(MBEDTLS_NET_C)
 #include "mbedtls/net_sockets.h"
 #endif
@@ -129,10 +141,26 @@
 #include "mbedtls/pkcs5.h"
 #endif
 
+#if defined(MBEDTLS_RIPEMD160_C)
+#include "mbedtls/ripemd160.h"
+#endif
+
 #if defined(MBEDTLS_RSA_C)
 #include "mbedtls/rsa.h"
 #endif
 
+#if defined(MBEDTLS_SHA1_C)
+#include "mbedtls/sha1.h"
+#endif
+
+#if defined(MBEDTLS_SHA256_C)
+#include "mbedtls/sha256.h"
+#endif
+
+#if defined(MBEDTLS_SHA512_C)
+#include "mbedtls/sha512.h"
+#endif
+
 #if defined(MBEDTLS_SSL_TLS_C)
 #include "mbedtls/ssl.h"
 #endif
@@ -635,6 +663,21 @@
         mbedtls_snprintf( buf, buflen, "HMAC_DRBG - The entropy source failed" );
 #endif /* MBEDTLS_HMAC_DRBG_C */
 
+#if defined(MBEDTLS_MD2_C)
+    if( use_ret == -(MBEDTLS_ERR_MD2_HW_ACCEL_FAILED) )
+        mbedtls_snprintf( buf, buflen, "MD2 - MD2 hardware accelerator failed" );
+#endif /* MBEDTLS_MD2_C */
+
+#if defined(MBEDTLS_MD4_C)
+    if( use_ret == -(MBEDTLS_ERR_MD4_HW_ACCEL_FAILED) )
+        mbedtls_snprintf( buf, buflen, "MD4 - MD4 hardware accelerator failed" );
+#endif /* MBEDTLS_MD4_C */
+
+#if defined(MBEDTLS_MD5_C)
+    if( use_ret == -(MBEDTLS_ERR_MD5_HW_ACCEL_FAILED) )
+        mbedtls_snprintf( buf, buflen, "MD5 - MD5 hardware accelerator failed" );
+#endif /* MBEDTLS_MD5_C */
+
 #if defined(MBEDTLS_NET_C)
     if( use_ret == -(MBEDTLS_ERR_NET_SOCKET_FAILED) )
         mbedtls_snprintf( buf, buflen, "NET - Failed to open a socket" );
@@ -672,6 +715,26 @@
         mbedtls_snprintf( buf, buflen, "PADLOCK - Input data should be aligned" );
 #endif /* MBEDTLS_PADLOCK_C */
 
+#if defined(MBEDTLS_RIPEMD160_C)
+    if( use_ret == -(MBEDTLS_ERR_RIPEMD160_HW_ACCEL_FAILED) )
+        mbedtls_snprintf( buf, buflen, "RIPEMD160 - RIPEMD160 hardware accelerator failed" );
+#endif /* MBEDTLS_RIPEMD160_C */
+
+#if defined(MBEDTLS_SHA1_C)
+    if( use_ret == -(MBEDTLS_ERR_SHA1_HW_ACCEL_FAILED) )
+        mbedtls_snprintf( buf, buflen, "SHA1 - SHA-1 hardware accelerator failed" );
+#endif /* MBEDTLS_SHA1_C */
+
+#if defined(MBEDTLS_SHA256_C)
+    if( use_ret == -(MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED) )
+        mbedtls_snprintf( buf, buflen, "SHA256 - SHA-256 hardware accelerator failed" );
+#endif /* MBEDTLS_SHA256_C */
+
+#if defined(MBEDTLS_SHA512_C)
+    if( use_ret == -(MBEDTLS_ERR_SHA512_HW_ACCEL_FAILED) )
+        mbedtls_snprintf( buf, buflen, "SHA512 - SHA-512 hardware accelerator failed" );
+#endif /* MBEDTLS_SHA512_C */
+
 #if defined(MBEDTLS_THREADING_C)
     if( use_ret == -(MBEDTLS_ERR_THREADING_FEATURE_UNAVAILABLE) )
         mbedtls_snprintf( buf, buflen, "THREADING - The selected feature is not available" );
diff --git a/library/md.c b/library/md.c
index 75b9717..00249af 100644
--- a/library/md.c
+++ b/library/md.c
@@ -250,9 +250,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->starts_func( ctx->md_ctx );
-
-    return( 0 );
+    return( ctx->md_info->starts_func( ctx->md_ctx ) );
 }
 
 int mbedtls_md_update( mbedtls_md_context_t *ctx, const unsigned char *input, size_t ilen )
@@ -260,9 +258,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->update_func( ctx->md_ctx, input, ilen );
-
-    return( 0 );
+    return( ctx->md_info->update_func( ctx->md_ctx, input, ilen ) );
 }
 
 int mbedtls_md_finish( mbedtls_md_context_t *ctx, unsigned char *output )
@@ -270,9 +266,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->finish_func( ctx->md_ctx, output );
-
-    return( 0 );
+    return( ctx->md_info->finish_func( ctx->md_ctx, output ) );
 }
 
 int mbedtls_md( const mbedtls_md_info_t *md_info, const unsigned char *input, size_t ilen,
@@ -281,9 +275,7 @@
     if( md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    md_info->digest_func( input, ilen, output );
-
-    return( 0 );
+    return( md_info->digest_func( input, ilen, output ) );
 }
 
 #if defined(MBEDTLS_FS_IO)
@@ -306,19 +298,20 @@
     if( ( ret = mbedtls_md_setup( &ctx, md_info, 0 ) ) != 0 )
         goto cleanup;
 
-    md_info->starts_func( ctx.md_ctx );
+    if( ( ret = md_info->starts_func( ctx.md_ctx ) ) != 0 )
+        goto cleanup;
 
     while( ( n = fread( buf, 1, sizeof( buf ), f ) ) > 0 )
-        md_info->update_func( ctx.md_ctx, buf, n );
+        if( ( ret = md_info->update_func( ctx.md_ctx, buf, n ) ) != 0 )
+            goto cleanup;
 
     if( ferror( f ) != 0 )
         ret = MBEDTLS_ERR_MD_FILE_IO_ERROR;
     else
-        md_info->finish_func( ctx.md_ctx, output );
-
-    mbedtls_zeroize( buf, sizeof( buf ) );
+        ret = md_info->finish_func( ctx.md_ctx, output );
 
 cleanup:
+    mbedtls_zeroize( buf, sizeof( buf ) );
     fclose( f );
     mbedtls_md_free( &ctx );
 
@@ -328,6 +321,7 @@
 
 int mbedtls_md_hmac_starts( mbedtls_md_context_t *ctx, const unsigned char *key, size_t keylen )
 {
+    int ret;
     unsigned char sum[MBEDTLS_MD_MAX_SIZE];
     unsigned char *ipad, *opad;
     size_t i;
@@ -337,9 +331,12 @@
 
     if( keylen > (size_t) ctx->md_info->block_size )
     {
-        ctx->md_info->starts_func( ctx->md_ctx );
-        ctx->md_info->update_func( ctx->md_ctx, key, keylen );
-        ctx->md_info->finish_func( ctx->md_ctx, sum );
+        if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+            goto cleanup;
+        if( ( ret = ctx->md_info->update_func( ctx->md_ctx, key, keylen ) ) != 0 )
+            goto cleanup;
+        if( ( ret = ctx->md_info->finish_func( ctx->md_ctx, sum ) ) != 0 )
+            goto cleanup;
 
         keylen = ctx->md_info->size;
         key = sum;
@@ -357,12 +354,16 @@
         opad[i] = (unsigned char)( opad[i] ^ key[i] );
     }
 
+    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+        goto cleanup;
+    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, ipad,
+                                           ctx->md_info->block_size ) ) != 0 )
+        goto cleanup;
+
+cleanup:
     mbedtls_zeroize( sum, sizeof( sum ) );
 
-    ctx->md_info->starts_func( ctx->md_ctx );
-    ctx->md_info->update_func( ctx->md_ctx, ipad, ctx->md_info->block_size );
-
-    return( 0 );
+    return( ret );
 }
 
 int mbedtls_md_hmac_update( mbedtls_md_context_t *ctx, const unsigned char *input, size_t ilen )
@@ -370,13 +371,12 @@
     if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->update_func( ctx->md_ctx, input, ilen );
-
-    return( 0 );
+    return( ctx->md_info->update_func( ctx->md_ctx, input, ilen ) );
 }
 
 int mbedtls_md_hmac_finish( mbedtls_md_context_t *ctx, unsigned char *output )
 {
+    int ret;
     unsigned char tmp[MBEDTLS_MD_MAX_SIZE];
     unsigned char *opad;
 
@@ -385,17 +385,22 @@
 
     opad = (unsigned char *) ctx->hmac_ctx + ctx->md_info->block_size;
 
-    ctx->md_info->finish_func( ctx->md_ctx, tmp );
-    ctx->md_info->starts_func( ctx->md_ctx );
-    ctx->md_info->update_func( ctx->md_ctx, opad, ctx->md_info->block_size );
-    ctx->md_info->update_func( ctx->md_ctx, tmp, ctx->md_info->size );
-    ctx->md_info->finish_func( ctx->md_ctx, output );
-
-    return( 0 );
+    if( ( ret = ctx->md_info->finish_func( ctx->md_ctx, tmp ) ) != 0 )
+        return( ret );
+    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+        return( ret );
+    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, opad,
+                                           ctx->md_info->block_size ) ) != 0 )
+        return( ret );
+    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, tmp,
+                                           ctx->md_info->size ) ) != 0 )
+        return( ret );
+    return( ctx->md_info->finish_func( ctx->md_ctx, output ) );
 }
 
 int mbedtls_md_hmac_reset( mbedtls_md_context_t *ctx )
 {
+    int ret;
     unsigned char *ipad;
 
     if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
@@ -403,15 +408,16 @@
 
     ipad = (unsigned char *) ctx->hmac_ctx;
 
-    ctx->md_info->starts_func( ctx->md_ctx );
-    ctx->md_info->update_func( ctx->md_ctx, ipad, ctx->md_info->block_size );
-
-    return( 0 );
+    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
+        return( ret );
+    return( ctx->md_info->update_func( ctx->md_ctx, ipad,
+                                       ctx->md_info->block_size ) );
 }
 
-int mbedtls_md_hmac( const mbedtls_md_info_t *md_info, const unsigned char *key, size_t keylen,
-                const unsigned char *input, size_t ilen,
-                unsigned char *output )
+int mbedtls_md_hmac( const mbedtls_md_info_t *md_info,
+                     const unsigned char *key, size_t keylen,
+                     const unsigned char *input, size_t ilen,
+                     unsigned char *output )
 {
     mbedtls_md_context_t ctx;
     int ret;
@@ -422,15 +428,19 @@
     mbedtls_md_init( &ctx );
 
     if( ( ret = mbedtls_md_setup( &ctx, md_info, 1 ) ) != 0 )
-        return( ret );
+        goto cleanup;
 
-    mbedtls_md_hmac_starts( &ctx, key, keylen );
-    mbedtls_md_hmac_update( &ctx, input, ilen );
-    mbedtls_md_hmac_finish( &ctx, output );
+    if( ( ret = mbedtls_md_hmac_starts( &ctx, key, keylen ) ) != 0 )
+        goto cleanup;
+    if( ( ret = mbedtls_md_hmac_update( &ctx, input, ilen ) ) != 0 )
+        goto cleanup;
+    if( ( ret = mbedtls_md_hmac_finish( &ctx, output ) ) != 0 )
+        goto cleanup;
 
+cleanup:
     mbedtls_md_free( &ctx );
 
-    return( 0 );
+    return( ret );
 }
 
 int mbedtls_md_process( mbedtls_md_context_t *ctx, const unsigned char *data )
@@ -438,9 +448,7 @@
     if( ctx == NULL || ctx->md_info == NULL )
         return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
 
-    ctx->md_info->process_func( ctx->md_ctx, data );
-
-    return( 0 );
+    return( ctx->md_info->process_func( ctx->md_ctx, data ) );
 }
 
 unsigned char mbedtls_md_get_size( const mbedtls_md_info_t *md_info )
diff --git a/library/md2.c b/library/md2.c
index 95cbcce..5028e8c 100644
--- a/library/md2.c
+++ b/library/md2.c
@@ -105,16 +105,18 @@
 /*
  * MD2 context setup
  */
-void mbedtls_md2_starts( mbedtls_md2_context *ctx )
+int mbedtls_md2_starts_ret( mbedtls_md2_context *ctx )
 {
     memset( ctx->cksum, 0, 16 );
     memset( ctx->state, 0, 46 );
     memset( ctx->buffer, 0, 16 );
     ctx->left = 0;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_MD2_PROCESS_ALT)
-void mbedtls_md2_process( mbedtls_md2_context *ctx )
+int mbedtls_internal_md2_process( mbedtls_md2_context *ctx )
 {
     int i, j;
     unsigned char t = 0;
@@ -146,14 +148,19 @@
            ( ctx->cksum[i] ^ PI_SUBST[ctx->buffer[i] ^ t] );
         t  = ctx->cksum[i];
     }
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_MD2_PROCESS_ALT */
 
 /*
  * MD2 process buffer
  */
-void mbedtls_md2_update( mbedtls_md2_context *ctx, const unsigned char *input, size_t ilen )
+int mbedtls_md2_update_ret( mbedtls_md2_context *ctx,
+                            const unsigned char *input,
+                            size_t ilen )
 {
+    int ret;
     size_t fill;
 
     while( ilen > 0 )
@@ -172,16 +179,21 @@
         if( ctx->left == 16 )
         {
             ctx->left = 0;
-            mbedtls_md2_process( ctx );
+            if( ( ret = mbedtls_internal_md2_process( ctx ) ) != 0 )
+                return( ret );
         }
     }
+
+    return( 0 );
 }
 
 /*
  * MD2 final digest
  */
-void mbedtls_md2_finish( mbedtls_md2_context *ctx, unsigned char output[16] )
+int mbedtls_md2_finish_ret( mbedtls_md2_context *ctx,
+                            unsigned char output[16] )
 {
+    int ret;
     size_t i;
     unsigned char x;
 
@@ -190,12 +202,16 @@
     for( i = ctx->left; i < 16; i++ )
         ctx->buffer[i] = x;
 
-    mbedtls_md2_process( ctx );
+    if( ( ret = mbedtls_internal_md2_process( ctx ) ) != 0 )
+        return( ret );
 
     memcpy( ctx->buffer, ctx->cksum, 16 );
-    mbedtls_md2_process( ctx );
+    if( ( ret = mbedtls_internal_md2_process( ctx ) ) != 0 )
+        return( ret );
 
     memcpy( output, ctx->state, 16 );
+
+    return( 0 );
 }
 
 #endif /* !MBEDTLS_MD2_ALT */
@@ -203,15 +219,28 @@
 /*
  * output = MD2( input buffer )
  */
-void mbedtls_md2( const unsigned char *input, size_t ilen, unsigned char output[16] )
+int mbedtls_md2_ret( const unsigned char *input,
+                     size_t ilen,
+                     unsigned char output[16] )
 {
+    int ret;
     mbedtls_md2_context ctx;
 
     mbedtls_md2_init( &ctx );
-    mbedtls_md2_starts( &ctx );
-    mbedtls_md2_update( &ctx, input, ilen );
-    mbedtls_md2_finish( &ctx, output );
+
+    if( ( ret = mbedtls_md2_starts_ret( &ctx ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md2_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md2_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_md2_free( &ctx );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -219,7 +248,7 @@
 /*
  * RFC 1319 test vectors
  */
-static const char md2_test_str[7][81] =
+static const unsigned char md2_test_str[7][81] =
 {
     { "" },
     { "a" },
@@ -227,10 +256,15 @@
     { "message digest" },
     { "abcdefghijklmnopqrstuvwxyz" },
     { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
-    { "12345678901234567890123456789012345678901234567890123456789012" \
+    { "12345678901234567890123456789012345678901234567890123456789012"
       "345678901234567890" }
 };
 
+static const size_t md2_test_strlen[7] =
+{
+    0, 1, 3, 14, 26, 62, 80
+};
+
 static const unsigned char md2_test_sum[7][16] =
 {
     { 0x83, 0x50, 0xE5, 0xA3, 0xE2, 0x4C, 0x15, 0x3D,
@@ -254,7 +288,7 @@
  */
 int mbedtls_md2_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char md2sum[16];
 
     for( i = 0; i < 7; i++ )
@@ -262,15 +296,14 @@
         if( verbose != 0 )
             mbedtls_printf( "  MD2 test #%d: ", i + 1 );
 
-        mbedtls_md2( (unsigned char *) md2_test_str[i],
-             strlen( md2_test_str[i] ), md2sum );
+        ret = mbedtls_md2_ret( md2_test_str[i], md2_test_strlen[i], md2sum );
+        if( ret != 0 )
+            goto fail;
 
         if( memcmp( md2sum, md2_test_sum[i], 16 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
+            ret = 1;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -281,6 +314,12 @@
         mbedtls_printf( "\n" );
 
     return( 0 );
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/library/md4.c b/library/md4.c
index 11a77e3..34a4b0e 100644
--- a/library/md4.c
+++ b/library/md4.c
@@ -98,7 +98,7 @@
 /*
  * MD4 context setup
  */
-void mbedtls_md4_starts( mbedtls_md4_context *ctx )
+int mbedtls_md4_starts_ret( mbedtls_md4_context *ctx )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -107,10 +107,13 @@
     ctx->state[1] = 0xEFCDAB89;
     ctx->state[2] = 0x98BADCFE;
     ctx->state[3] = 0x10325476;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_MD4_PROCESS_ALT)
-void mbedtls_md4_process( mbedtls_md4_context *ctx, const unsigned char data[64] )
+int mbedtls_internal_md4_process( mbedtls_md4_context *ctx,
+                                  const unsigned char data[64] )
 {
     uint32_t X[16], A, B, C, D;
 
@@ -211,19 +214,24 @@
     ctx->state[1] += B;
     ctx->state[2] += C;
     ctx->state[3] += D;
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_MD4_PROCESS_ALT */
 
 /*
  * MD4 process buffer
  */
-void mbedtls_md4_update( mbedtls_md4_context *ctx, const unsigned char *input, size_t ilen )
+int mbedtls_md4_update_ret( mbedtls_md4_context *ctx,
+                            const unsigned char *input,
+                            size_t ilen )
 {
+    int ret;
     size_t fill;
     uint32_t left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = ctx->total[0] & 0x3F;
     fill = 64 - left;
@@ -238,7 +246,10 @@
     {
         memcpy( (void *) (ctx->buffer + left),
                 (void *) input, fill );
-        mbedtls_md4_process( ctx, ctx->buffer );
+
+        if( ( ret = mbedtls_internal_md4_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -246,7 +257,9 @@
 
     while( ilen >= 64 )
     {
-        mbedtls_md4_process( ctx, input );
+        if( ( ret = mbedtls_internal_md4_process( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 64;
         ilen  -= 64;
     }
@@ -256,6 +269,8 @@
         memcpy( (void *) (ctx->buffer + left),
                 (void *) input, ilen );
     }
+
+    return( 0 );
 }
 
 static const unsigned char md4_padding[64] =
@@ -269,8 +284,10 @@
 /*
  * MD4 final digest
  */
-void mbedtls_md4_finish( mbedtls_md4_context *ctx, unsigned char output[16] )
+int mbedtls_md4_finish_ret( mbedtls_md4_context *ctx,
+                            unsigned char output[16] )
 {
+    int ret;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -285,13 +302,20 @@
     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
 
-    mbedtls_md4_update( ctx, (unsigned char *) md4_padding, padn );
-    mbedtls_md4_update( ctx, msglen, 8 );
+    ret = mbedtls_md4_update_ret( ctx, (unsigned char *)md4_padding, padn );
+    if( ret != 0 )
+        return( ret );
+
+    if( ( ret = mbedtls_md4_update_ret( ctx, msglen, 8 ) ) != 0 )
+        return( ret );
+
 
     PUT_UINT32_LE( ctx->state[0], output,  0 );
     PUT_UINT32_LE( ctx->state[1], output,  4 );
     PUT_UINT32_LE( ctx->state[2], output,  8 );
     PUT_UINT32_LE( ctx->state[3], output, 12 );
+
+    return( 0 );
 }
 
 #endif /* !MBEDTLS_MD4_ALT */
@@ -299,15 +323,28 @@
 /*
  * output = MD4( input buffer )
  */
-void mbedtls_md4( const unsigned char *input, size_t ilen, unsigned char output[16] )
+int mbedtls_md4_ret( const unsigned char *input,
+                     size_t ilen,
+                     unsigned char output[16] )
 {
+    int ret;
     mbedtls_md4_context ctx;
 
     mbedtls_md4_init( &ctx );
-    mbedtls_md4_starts( &ctx );
-    mbedtls_md4_update( &ctx, input, ilen );
-    mbedtls_md4_finish( &ctx, output );
+
+    if( ( ret = mbedtls_md4_starts_ret( &ctx ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md4_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md4_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_md4_free( &ctx );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -315,7 +352,7 @@
 /*
  * RFC 1320 test vectors
  */
-static const char md4_test_str[7][81] =
+static const unsigned char md4_test_str[7][81] =
 {
     { "" },
     { "a" },
@@ -323,10 +360,15 @@
     { "message digest" },
     { "abcdefghijklmnopqrstuvwxyz" },
     { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
-    { "12345678901234567890123456789012345678901234567890123456789012" \
+    { "12345678901234567890123456789012345678901234567890123456789012"
       "345678901234567890" }
 };
 
+static const size_t md4_test_strlen[7] =
+{
+    0, 1, 3, 14, 26, 62, 80
+};
+
 static const unsigned char md4_test_sum[7][16] =
 {
     { 0x31, 0xD6, 0xCF, 0xE0, 0xD1, 0x6A, 0xE9, 0x31,
@@ -350,7 +392,7 @@
  */
 int mbedtls_md4_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char md4sum[16];
 
     for( i = 0; i < 7; i++ )
@@ -358,15 +400,14 @@
         if( verbose != 0 )
             mbedtls_printf( "  MD4 test #%d: ", i + 1 );
 
-        mbedtls_md4( (unsigned char *) md4_test_str[i],
-             strlen( md4_test_str[i] ), md4sum );
+        ret = mbedtls_md4_ret( md4_test_str[i], md4_test_strlen[i], md4sum );
+        if( ret != 0 )
+            goto fail;
 
         if( memcmp( md4sum, md4_test_sum[i], 16 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
+            ret = 1;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -377,6 +418,12 @@
         mbedtls_printf( "\n" );
 
     return( 0 );
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/library/md5.c b/library/md5.c
index 5d972dc..8872dc4 100644
--- a/library/md5.c
+++ b/library/md5.c
@@ -97,7 +97,7 @@
 /*
  * MD5 context setup
  */
-void mbedtls_md5_starts( mbedtls_md5_context *ctx )
+int mbedtls_md5_starts_ret( mbedtls_md5_context *ctx )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -106,10 +106,13 @@
     ctx->state[1] = 0xEFCDAB89;
     ctx->state[2] = 0x98BADCFE;
     ctx->state[3] = 0x10325476;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_MD5_PROCESS_ALT)
-void mbedtls_md5_process( mbedtls_md5_context *ctx, const unsigned char data[64] )
+int mbedtls_internal_md5_process( mbedtls_md5_context *ctx,
+                                  const unsigned char data[64] )
 {
     uint32_t X[16], A, B, C, D;
 
@@ -230,19 +233,24 @@
     ctx->state[1] += B;
     ctx->state[2] += C;
     ctx->state[3] += D;
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_MD5_PROCESS_ALT */
 
 /*
  * MD5 process buffer
  */
-void mbedtls_md5_update( mbedtls_md5_context *ctx, const unsigned char *input, size_t ilen )
+int mbedtls_md5_update_ret( mbedtls_md5_context *ctx,
+                            const unsigned char *input,
+                            size_t ilen )
 {
+    int ret;
     size_t fill;
     uint32_t left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = ctx->total[0] & 0x3F;
     fill = 64 - left;
@@ -256,7 +264,9 @@
     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
-        mbedtls_md5_process( ctx, ctx->buffer );
+        if( ( ret = mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -264,7 +274,9 @@
 
     while( ilen >= 64 )
     {
-        mbedtls_md5_process( ctx, input );
+        if( ( ret = mbedtls_internal_md5_process( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 64;
         ilen  -= 64;
     }
@@ -273,6 +285,8 @@
     {
         memcpy( (void *) (ctx->buffer + left), input, ilen );
     }
+
+    return( 0 );
 }
 
 static const unsigned char md5_padding[64] =
@@ -286,8 +300,10 @@
 /*
  * MD5 final digest
  */
-void mbedtls_md5_finish( mbedtls_md5_context *ctx, unsigned char output[16] )
+int mbedtls_md5_finish_ret( mbedtls_md5_context *ctx,
+                            unsigned char output[16] )
 {
+    int ret;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -302,13 +318,18 @@
     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
 
-    mbedtls_md5_update( ctx, md5_padding, padn );
-    mbedtls_md5_update( ctx, msglen, 8 );
+    if( ( ret = mbedtls_md5_update_ret( ctx, md5_padding, padn ) ) != 0 )
+            return( ret );
+
+    if( ( ret = mbedtls_md5_update_ret( ctx, msglen, 8 ) ) != 0 )
+            return( ret );
 
     PUT_UINT32_LE( ctx->state[0], output,  0 );
     PUT_UINT32_LE( ctx->state[1], output,  4 );
     PUT_UINT32_LE( ctx->state[2], output,  8 );
     PUT_UINT32_LE( ctx->state[3], output, 12 );
+
+    return( 0 );
 }
 
 #endif /* !MBEDTLS_MD5_ALT */
@@ -316,15 +337,28 @@
 /*
  * output = MD5( input buffer )
  */
-void mbedtls_md5( const unsigned char *input, size_t ilen, unsigned char output[16] )
+int mbedtls_md5_ret( const unsigned char *input,
+                     size_t ilen,
+                     unsigned char output[16] )
 {
+    int ret;
     mbedtls_md5_context ctx;
 
     mbedtls_md5_init( &ctx );
-    mbedtls_md5_starts( &ctx );
-    mbedtls_md5_update( &ctx, input, ilen );
-    mbedtls_md5_finish( &ctx, output );
+
+    if( ( ret = mbedtls_md5_starts_ret( &ctx ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md5_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_md5_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_md5_free( &ctx );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -339,11 +373,11 @@
     { "message digest" },
     { "abcdefghijklmnopqrstuvwxyz" },
     { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
-    { "12345678901234567890123456789012345678901234567890123456789012" \
+    { "12345678901234567890123456789012345678901234567890123456789012"
       "345678901234567890" }
 };
 
-static const int md5_test_buflen[7] =
+static const size_t md5_test_buflen[7] =
 {
     0, 1, 3, 14, 26, 62, 80
 };
@@ -371,7 +405,7 @@
  */
 int mbedtls_md5_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char md5sum[16];
 
     for( i = 0; i < 7; i++ )
@@ -379,14 +413,14 @@
         if( verbose != 0 )
             mbedtls_printf( "  MD5 test #%d: ", i + 1 );
 
-        mbedtls_md5( md5_test_buf[i], md5_test_buflen[i], md5sum );
+        ret = mbedtls_md5_ret( md5_test_buf[i], md5_test_buflen[i], md5sum );
+        if( ret != 0 )
+            goto fail;
 
         if( memcmp( md5sum, md5_test_sum[i], 16 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
+            ret = 1;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -397,6 +431,12 @@
         mbedtls_printf( "\n" );
 
     return( 0 );
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/library/md_wrap.c b/library/md_wrap.c
index 2cfcae2..32f0871 100644
--- a/library/md_wrap.c
+++ b/library/md_wrap.c
@@ -71,20 +71,20 @@
 
 #if defined(MBEDTLS_MD2_C)
 
-static void md2_starts_wrap( void *ctx )
+static int md2_starts_wrap( void *ctx )
 {
-    mbedtls_md2_starts( (mbedtls_md2_context *) ctx );
+    return( mbedtls_md2_starts_ret( (mbedtls_md2_context *) ctx ) );
 }
 
-static void md2_update_wrap( void *ctx, const unsigned char *input,
+static int md2_update_wrap( void *ctx, const unsigned char *input,
                              size_t ilen )
 {
-    mbedtls_md2_update( (mbedtls_md2_context *) ctx, input, ilen );
+    return( mbedtls_md2_update_ret( (mbedtls_md2_context *) ctx, input, ilen ) );
 }
 
-static void md2_finish_wrap( void *ctx, unsigned char *output )
+static int md2_finish_wrap( void *ctx, unsigned char *output )
 {
-    mbedtls_md2_finish( (mbedtls_md2_context *) ctx, output );
+    return( mbedtls_md2_finish_ret( (mbedtls_md2_context *) ctx, output ) );
 }
 
 static void *md2_ctx_alloc( void )
@@ -109,11 +109,11 @@
                  (const mbedtls_md2_context *) src );
 }
 
-static void md2_process_wrap( void *ctx, const unsigned char *data )
+static int md2_process_wrap( void *ctx, const unsigned char *data )
 {
     ((void) data);
 
-    mbedtls_md2_process( (mbedtls_md2_context *) ctx );
+    return( mbedtls_internal_md2_process( (mbedtls_md2_context *) ctx ) );
 }
 
 const mbedtls_md_info_t mbedtls_md2_info = {
@@ -124,7 +124,7 @@
     md2_starts_wrap,
     md2_update_wrap,
     md2_finish_wrap,
-    mbedtls_md2,
+    mbedtls_md2_ret,
     md2_ctx_alloc,
     md2_ctx_free,
     md2_clone_wrap,
@@ -135,20 +135,20 @@
 
 #if defined(MBEDTLS_MD4_C)
 
-static void md4_starts_wrap( void *ctx )
+static int md4_starts_wrap( void *ctx )
 {
-    mbedtls_md4_starts( (mbedtls_md4_context *) ctx );
+    return( mbedtls_md4_starts_ret( (mbedtls_md4_context *) ctx ) );
 }
 
-static void md4_update_wrap( void *ctx, const unsigned char *input,
+static int md4_update_wrap( void *ctx, const unsigned char *input,
                              size_t ilen )
 {
-    mbedtls_md4_update( (mbedtls_md4_context *) ctx, input, ilen );
+    return( mbedtls_md4_update_ret( (mbedtls_md4_context *) ctx, input, ilen ) );
 }
 
-static void md4_finish_wrap( void *ctx, unsigned char *output )
+static int md4_finish_wrap( void *ctx, unsigned char *output )
 {
-    mbedtls_md4_finish( (mbedtls_md4_context *) ctx, output );
+    return( mbedtls_md4_finish_ret( (mbedtls_md4_context *) ctx, output ) );
 }
 
 static void *md4_ctx_alloc( void )
@@ -170,12 +170,12 @@
 static void md4_clone_wrap( void *dst, const void *src )
 {
     mbedtls_md4_clone( (mbedtls_md4_context *) dst,
-                 (const mbedtls_md4_context *) src );
+                       (const mbedtls_md4_context *) src );
 }
 
-static void md4_process_wrap( void *ctx, const unsigned char *data )
+static int md4_process_wrap( void *ctx, const unsigned char *data )
 {
-    mbedtls_md4_process( (mbedtls_md4_context *) ctx, data );
+    return( mbedtls_internal_md4_process( (mbedtls_md4_context *) ctx, data ) );
 }
 
 const mbedtls_md_info_t mbedtls_md4_info = {
@@ -186,7 +186,7 @@
     md4_starts_wrap,
     md4_update_wrap,
     md4_finish_wrap,
-    mbedtls_md4,
+    mbedtls_md4_ret,
     md4_ctx_alloc,
     md4_ctx_free,
     md4_clone_wrap,
@@ -197,20 +197,20 @@
 
 #if defined(MBEDTLS_MD5_C)
 
-static void md5_starts_wrap( void *ctx )
+static int md5_starts_wrap( void *ctx )
 {
-    mbedtls_md5_starts( (mbedtls_md5_context *) ctx );
+    return( mbedtls_md5_starts_ret( (mbedtls_md5_context *) ctx ) );
 }
 
-static void md5_update_wrap( void *ctx, const unsigned char *input,
+static int md5_update_wrap( void *ctx, const unsigned char *input,
                              size_t ilen )
 {
-    mbedtls_md5_update( (mbedtls_md5_context *) ctx, input, ilen );
+    return( mbedtls_md5_update_ret( (mbedtls_md5_context *) ctx, input, ilen ) );
 }
 
-static void md5_finish_wrap( void *ctx, unsigned char *output )
+static int md5_finish_wrap( void *ctx, unsigned char *output )
 {
-    mbedtls_md5_finish( (mbedtls_md5_context *) ctx, output );
+    return( mbedtls_md5_finish_ret( (mbedtls_md5_context *) ctx, output ) );
 }
 
 static void *md5_ctx_alloc( void )
@@ -232,12 +232,12 @@
 static void md5_clone_wrap( void *dst, const void *src )
 {
     mbedtls_md5_clone( (mbedtls_md5_context *) dst,
-                 (const mbedtls_md5_context *) src );
+                       (const mbedtls_md5_context *) src );
 }
 
-static void md5_process_wrap( void *ctx, const unsigned char *data )
+static int md5_process_wrap( void *ctx, const unsigned char *data )
 {
-    mbedtls_md5_process( (mbedtls_md5_context *) ctx, data );
+    return( mbedtls_internal_md5_process( (mbedtls_md5_context *) ctx, data ) );
 }
 
 const mbedtls_md_info_t mbedtls_md5_info = {
@@ -248,7 +248,7 @@
     md5_starts_wrap,
     md5_update_wrap,
     md5_finish_wrap,
-    mbedtls_md5,
+    mbedtls_md5_ret,
     md5_ctx_alloc,
     md5_ctx_free,
     md5_clone_wrap,
@@ -259,20 +259,22 @@
 
 #if defined(MBEDTLS_RIPEMD160_C)
 
-static void ripemd160_starts_wrap( void *ctx )
+static int ripemd160_starts_wrap( void *ctx )
 {
-    mbedtls_ripemd160_starts( (mbedtls_ripemd160_context *) ctx );
+    return( mbedtls_ripemd160_starts_ret( (mbedtls_ripemd160_context *) ctx ) );
 }
 
-static void ripemd160_update_wrap( void *ctx, const unsigned char *input,
+static int ripemd160_update_wrap( void *ctx, const unsigned char *input,
                                    size_t ilen )
 {
-    mbedtls_ripemd160_update( (mbedtls_ripemd160_context *) ctx, input, ilen );
+    return( mbedtls_ripemd160_update_ret( (mbedtls_ripemd160_context *) ctx,
+                                          input, ilen ) );
 }
 
-static void ripemd160_finish_wrap( void *ctx, unsigned char *output )
+static int ripemd160_finish_wrap( void *ctx, unsigned char *output )
 {
-    mbedtls_ripemd160_finish( (mbedtls_ripemd160_context *) ctx, output );
+    return( mbedtls_ripemd160_finish_ret( (mbedtls_ripemd160_context *) ctx,
+                                          output ) );
 }
 
 static void *ripemd160_ctx_alloc( void )
@@ -297,9 +299,10 @@
                        (const mbedtls_ripemd160_context *) src );
 }
 
-static void ripemd160_process_wrap( void *ctx, const unsigned char *data )
+static int ripemd160_process_wrap( void *ctx, const unsigned char *data )
 {
-    mbedtls_ripemd160_process( (mbedtls_ripemd160_context *) ctx, data );
+    return( mbedtls_internal_ripemd160_process(
+                                (mbedtls_ripemd160_context *) ctx, data ) );
 }
 
 const mbedtls_md_info_t mbedtls_ripemd160_info = {
@@ -310,7 +313,7 @@
     ripemd160_starts_wrap,
     ripemd160_update_wrap,
     ripemd160_finish_wrap,
-    mbedtls_ripemd160,
+    mbedtls_ripemd160_ret,
     ripemd160_ctx_alloc,
     ripemd160_ctx_free,
     ripemd160_clone_wrap,
@@ -321,20 +324,21 @@
 
 #if defined(MBEDTLS_SHA1_C)
 
-static void sha1_starts_wrap( void *ctx )
+static int sha1_starts_wrap( void *ctx )
 {
-    mbedtls_sha1_starts( (mbedtls_sha1_context *) ctx );
+    return( mbedtls_sha1_starts_ret( (mbedtls_sha1_context *) ctx ) );
 }
 
-static void sha1_update_wrap( void *ctx, const unsigned char *input,
+static int sha1_update_wrap( void *ctx, const unsigned char *input,
                               size_t ilen )
 {
-    mbedtls_sha1_update( (mbedtls_sha1_context *) ctx, input, ilen );
+    return( mbedtls_sha1_update_ret( (mbedtls_sha1_context *) ctx,
+                                     input, ilen ) );
 }
 
-static void sha1_finish_wrap( void *ctx, unsigned char *output )
+static int sha1_finish_wrap( void *ctx, unsigned char *output )
 {
-    mbedtls_sha1_finish( (mbedtls_sha1_context *) ctx, output );
+    return( mbedtls_sha1_finish_ret( (mbedtls_sha1_context *) ctx, output ) );
 }
 
 static void *sha1_ctx_alloc( void )
@@ -359,9 +363,10 @@
     mbedtls_free( ctx );
 }
 
-static void sha1_process_wrap( void *ctx, const unsigned char *data )
+static int sha1_process_wrap( void *ctx, const unsigned char *data )
 {
-    mbedtls_sha1_process( (mbedtls_sha1_context *) ctx, data );
+    return( mbedtls_internal_sha1_process( (mbedtls_sha1_context *) ctx,
+                                           data ) );
 }
 
 const mbedtls_md_info_t mbedtls_sha1_info = {
@@ -372,7 +377,7 @@
     sha1_starts_wrap,
     sha1_update_wrap,
     sha1_finish_wrap,
-    mbedtls_sha1,
+    mbedtls_sha1_ret,
     sha1_ctx_alloc,
     sha1_ctx_free,
     sha1_clone_wrap,
@@ -386,26 +391,28 @@
  */
 #if defined(MBEDTLS_SHA256_C)
 
-static void sha224_starts_wrap( void *ctx )
+static int sha224_starts_wrap( void *ctx )
 {
-    mbedtls_sha256_starts( (mbedtls_sha256_context *) ctx, 1 );
+    return( mbedtls_sha256_starts_ret( (mbedtls_sha256_context *) ctx, 1 ) );
 }
 
-static void sha224_update_wrap( void *ctx, const unsigned char *input,
+static int sha224_update_wrap( void *ctx, const unsigned char *input,
                                 size_t ilen )
 {
-    mbedtls_sha256_update( (mbedtls_sha256_context *) ctx, input, ilen );
+    return( mbedtls_sha256_update_ret( (mbedtls_sha256_context *) ctx,
+                                       input, ilen ) );
 }
 
-static void sha224_finish_wrap( void *ctx, unsigned char *output )
+static int sha224_finish_wrap( void *ctx, unsigned char *output )
 {
-    mbedtls_sha256_finish( (mbedtls_sha256_context *) ctx, output );
+    return( mbedtls_sha256_finish_ret( (mbedtls_sha256_context *) ctx,
+                                       output ) );
 }
 
-static void sha224_wrap( const unsigned char *input, size_t ilen,
-                    unsigned char *output )
+static int sha224_wrap( const unsigned char *input, size_t ilen,
+                        unsigned char *output )
 {
-    mbedtls_sha256( input, ilen, output, 1 );
+    return( mbedtls_sha256_ret( input, ilen, output, 1 ) );
 }
 
 static void *sha224_ctx_alloc( void )
@@ -430,9 +437,10 @@
                     (const mbedtls_sha256_context *) src );
 }
 
-static void sha224_process_wrap( void *ctx, const unsigned char *data )
+static int sha224_process_wrap( void *ctx, const unsigned char *data )
 {
-    mbedtls_sha256_process( (mbedtls_sha256_context *) ctx, data );
+    return( mbedtls_internal_sha256_process( (mbedtls_sha256_context *) ctx,
+                                             data ) );
 }
 
 const mbedtls_md_info_t mbedtls_sha224_info = {
@@ -450,15 +458,15 @@
     sha224_process_wrap,
 };
 
-static void sha256_starts_wrap( void *ctx )
+static int sha256_starts_wrap( void *ctx )
 {
-    mbedtls_sha256_starts( (mbedtls_sha256_context *) ctx, 0 );
+    return( mbedtls_sha256_starts_ret( (mbedtls_sha256_context *) ctx, 0 ) );
 }
 
-static void sha256_wrap( const unsigned char *input, size_t ilen,
-                    unsigned char *output )
+static int sha256_wrap( const unsigned char *input, size_t ilen,
+                        unsigned char *output )
 {
-    mbedtls_sha256( input, ilen, output, 0 );
+    return( mbedtls_sha256_ret( input, ilen, output, 0 ) );
 }
 
 const mbedtls_md_info_t mbedtls_sha256_info = {
@@ -480,26 +488,28 @@
 
 #if defined(MBEDTLS_SHA512_C)
 
-static void sha384_starts_wrap( void *ctx )
+static int sha384_starts_wrap( void *ctx )
 {
-    mbedtls_sha512_starts( (mbedtls_sha512_context *) ctx, 1 );
+    return( mbedtls_sha512_starts_ret( (mbedtls_sha512_context *) ctx, 1 ) );
 }
 
-static void sha384_update_wrap( void *ctx, const unsigned char *input,
-                                size_t ilen )
+static int sha384_update_wrap( void *ctx, const unsigned char *input,
+                               size_t ilen )
 {
-    mbedtls_sha512_update( (mbedtls_sha512_context *) ctx, input, ilen );
+    return( mbedtls_sha512_update_ret( (mbedtls_sha512_context *) ctx,
+                                       input, ilen ) );
 }
 
-static void sha384_finish_wrap( void *ctx, unsigned char *output )
+static int sha384_finish_wrap( void *ctx, unsigned char *output )
 {
-    mbedtls_sha512_finish( (mbedtls_sha512_context *) ctx, output );
+    return( mbedtls_sha512_finish_ret( (mbedtls_sha512_context *) ctx,
+                                       output ) );
 }
 
-static void sha384_wrap( const unsigned char *input, size_t ilen,
-                    unsigned char *output )
+static int sha384_wrap( const unsigned char *input, size_t ilen,
+                        unsigned char *output )
 {
-    mbedtls_sha512( input, ilen, output, 1 );
+    return( mbedtls_sha512_ret( input, ilen, output, 1 ) );
 }
 
 static void *sha384_ctx_alloc( void )
@@ -524,9 +534,10 @@
                     (const mbedtls_sha512_context *) src );
 }
 
-static void sha384_process_wrap( void *ctx, const unsigned char *data )
+static int sha384_process_wrap( void *ctx, const unsigned char *data )
 {
-    mbedtls_sha512_process( (mbedtls_sha512_context *) ctx, data );
+    return( mbedtls_internal_sha512_process( (mbedtls_sha512_context *) ctx,
+                                             data ) );
 }
 
 const mbedtls_md_info_t mbedtls_sha384_info = {
@@ -544,15 +555,15 @@
     sha384_process_wrap,
 };
 
-static void sha512_starts_wrap( void *ctx )
+static int sha512_starts_wrap( void *ctx )
 {
-    mbedtls_sha512_starts( (mbedtls_sha512_context *) ctx, 0 );
+    return( mbedtls_sha512_starts_ret( (mbedtls_sha512_context *) ctx, 0 ) );
 }
 
-static void sha512_wrap( const unsigned char *input, size_t ilen,
-                    unsigned char *output )
+static int sha512_wrap( const unsigned char *input, size_t ilen,
+                        unsigned char *output )
 {
-    mbedtls_sha512( input, ilen, output, 0 );
+    return( mbedtls_sha512_ret( input, ilen, output, 0 ) );
 }
 
 const mbedtls_md_info_t mbedtls_sha512_info = {
diff --git a/library/pem.c b/library/pem.c
index 756572d..c09651f 100644
--- a/library/pem.c
+++ b/library/pem.c
@@ -82,31 +82,33 @@
     return( 0 );
 }
 
-static void pem_pbkdf1( unsigned char *key, size_t keylen,
-                        unsigned char *iv,
-                        const unsigned char *pwd, size_t pwdlen )
+static int pem_pbkdf1( unsigned char *key, size_t keylen,
+                       unsigned char *iv,
+                       const unsigned char *pwd, size_t pwdlen )
 {
     mbedtls_md5_context md5_ctx;
     unsigned char md5sum[16];
     size_t use_len;
+    int ret;
 
     mbedtls_md5_init( &md5_ctx );
 
     /*
      * key[ 0..15] = MD5(pwd || IV)
      */
-    mbedtls_md5_starts( &md5_ctx );
-    mbedtls_md5_update( &md5_ctx, pwd, pwdlen );
-    mbedtls_md5_update( &md5_ctx, iv,  8 );
-    mbedtls_md5_finish( &md5_ctx, md5sum );
+    if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv,  8 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
+        goto exit;
 
     if( keylen <= 16 )
     {
         memcpy( key, md5sum, keylen );
-
-        mbedtls_md5_free( &md5_ctx );
-        mbedtls_zeroize( md5sum, 16 );
-        return;
+        goto exit;
     }
 
     memcpy( key, md5sum, 16 );
@@ -114,11 +116,16 @@
     /*
      * key[16..23] = MD5(key[ 0..15] || pwd || IV])
      */
-    mbedtls_md5_starts( &md5_ctx );
-    mbedtls_md5_update( &md5_ctx, md5sum,  16 );
-    mbedtls_md5_update( &md5_ctx, pwd, pwdlen );
-    mbedtls_md5_update( &md5_ctx, iv,  8 );
-    mbedtls_md5_finish( &md5_ctx, md5sum );
+    if( ( ret = mbedtls_md5_starts_ret( &md5_ctx ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, md5sum, 16 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, pwd, pwdlen ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_update_ret( &md5_ctx, iv, 8 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md5_finish_ret( &md5_ctx, md5sum ) ) != 0 )
+        goto exit;
 
     use_len = 16;
     if( keylen < 32 )
@@ -126,8 +133,11 @@
 
     memcpy( key + 16, md5sum, use_len );
 
+exit:
     mbedtls_md5_free( &md5_ctx );
     mbedtls_zeroize( md5sum, 16 );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_DES_C)
@@ -144,7 +154,8 @@
 
     mbedtls_des_init( &des_ctx );
 
-    pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen );
+    if( ( ret = pem_pbkdf1( des_key, 8, des_iv, pwd, pwdlen ) ) != 0 )
+        goto exit;
 
     if( ( ret = mbedtls_des_setkey_dec( &des_ctx, des_key ) ) != 0 )
         goto exit;
@@ -171,7 +182,8 @@
 
     mbedtls_des3_init( &des3_ctx );
 
-    pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen );
+    if( ( ret = pem_pbkdf1( des3_key, 24, des3_iv, pwd, pwdlen ) ) != 0 )
+        goto exit;
 
     if( ( ret = mbedtls_des3_set3key_dec( &des3_ctx, des3_key ) ) != 0 )
         goto exit;
@@ -200,7 +212,8 @@
 
     mbedtls_aes_init( &aes_ctx );
 
-    pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen );
+    if( ( ret = pem_pbkdf1( aes_key, keylen, aes_iv, pwd, pwdlen ) ) != 0 )
+        goto exit;
 
     if( ( ret = mbedtls_aes_setkey_dec( &aes_ctx, aes_key, keylen * 8 ) ) != 0 )
         goto exit;
diff --git a/library/ripemd160.c b/library/ripemd160.c
index cdb0a63..b85b117 100644
--- a/library/ripemd160.c
+++ b/library/ripemd160.c
@@ -46,6 +46,8 @@
 #endif /* MBEDTLS_PLATFORM_C */
 #endif /* MBEDTLS_SELF_TEST */
 
+#if !defined(MBEDTLS_RIPEMD160_ALT)
+
 /*
  * 32-bit integer manipulation macros (little endian)
  */
@@ -96,7 +98,7 @@
 /*
  * RIPEMD-160 context setup
  */
-void mbedtls_ripemd160_starts( mbedtls_ripemd160_context *ctx )
+int mbedtls_ripemd160_starts_ret( mbedtls_ripemd160_context *ctx )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -106,13 +108,16 @@
     ctx->state[2] = 0x98BADCFE;
     ctx->state[3] = 0x10325476;
     ctx->state[4] = 0xC3D2E1F0;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_RIPEMD160_PROCESS_ALT)
 /*
  * Process one block
  */
-void mbedtls_ripemd160_process( mbedtls_ripemd160_context *ctx, const unsigned char data[64] )
+int mbedtls_internal_ripemd160_process( mbedtls_ripemd160_context *ctx,
+                                        const unsigned char data[64] )
 {
     uint32_t A, B, C, D, E, Ap, Bp, Cp, Dp, Ep, X[16];
 
@@ -287,20 +292,24 @@
     ctx->state[3] = ctx->state[4] + A + Bp;
     ctx->state[4] = ctx->state[0] + B + Cp;
     ctx->state[0] = C;
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_RIPEMD160_PROCESS_ALT */
 
 /*
  * RIPEMD-160 process buffer
  */
-void mbedtls_ripemd160_update( mbedtls_ripemd160_context *ctx,
-                       const unsigned char *input, size_t ilen )
+int mbedtls_ripemd160_update_ret( mbedtls_ripemd160_context *ctx,
+                                  const unsigned char *input,
+                                  size_t ilen )
 {
+    int ret;
     size_t fill;
     uint32_t left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = ctx->total[0] & 0x3F;
     fill = 64 - left;
@@ -314,7 +323,10 @@
     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
-        mbedtls_ripemd160_process( ctx, ctx->buffer );
+
+        if( ( ret = mbedtls_internal_ripemd160_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -322,7 +334,9 @@
 
     while( ilen >= 64 )
     {
-        mbedtls_ripemd160_process( ctx, input );
+        if( ( ret = mbedtls_internal_ripemd160_process( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 64;
         ilen  -= 64;
     }
@@ -331,6 +345,8 @@
     {
         memcpy( (void *) (ctx->buffer + left), input, ilen );
     }
+
+    return( 0 );
 }
 
 static const unsigned char ripemd160_padding[64] =
@@ -344,8 +360,10 @@
 /*
  * RIPEMD-160 final digest
  */
-void mbedtls_ripemd160_finish( mbedtls_ripemd160_context *ctx, unsigned char output[20] )
+int mbedtls_ripemd160_finish_ret( mbedtls_ripemd160_context *ctx,
+                                  unsigned char output[20] )
 {
+    int ret;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -360,29 +378,50 @@
     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
 
-    mbedtls_ripemd160_update( ctx, ripemd160_padding, padn );
-    mbedtls_ripemd160_update( ctx, msglen, 8 );
+    ret = mbedtls_ripemd160_update_ret( ctx, ripemd160_padding, padn );
+    if( ret != 0 )
+        return( ret );
+
+    ret = mbedtls_ripemd160_update_ret( ctx, msglen, 8 );
+    if( ret != 0 )
+        return( ret );
 
     PUT_UINT32_LE( ctx->state[0], output,  0 );
     PUT_UINT32_LE( ctx->state[1], output,  4 );
     PUT_UINT32_LE( ctx->state[2], output,  8 );
     PUT_UINT32_LE( ctx->state[3], output, 12 );
     PUT_UINT32_LE( ctx->state[4], output, 16 );
+
+    return( 0 );
 }
 
+#endif /* ! MBEDTLS_RIPEMD160_ALT */
+
 /*
  * output = RIPEMD-160( input buffer )
  */
-void mbedtls_ripemd160( const unsigned char *input, size_t ilen,
-                unsigned char output[20] )
+int mbedtls_ripemd160_ret( const unsigned char *input,
+                           size_t ilen,
+                           unsigned char output[20] )
 {
+    int ret;
     mbedtls_ripemd160_context ctx;
 
     mbedtls_ripemd160_init( &ctx );
-    mbedtls_ripemd160_starts( &ctx );
-    mbedtls_ripemd160_update( &ctx, input, ilen );
-    mbedtls_ripemd160_finish( &ctx, output );
+
+    if( ( ret = mbedtls_ripemd160_starts_ret( &ctx ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_ripemd160_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_ripemd160_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_ripemd160_free( &ctx );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -391,18 +430,22 @@
  * http://homes.esat.kuleuven.be/~bosselae/mbedtls_ripemd160.html#HMAC
  */
 #define TESTS   8
-#define KEYS    2
-static const char *ripemd160_test_input[TESTS] =
+static const unsigned char ripemd160_test_str[TESTS][81] =
 {
-    "",
-    "a",
-    "abc",
-    "message digest",
-    "abcdefghijklmnopqrstuvwxyz",
-    "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
-    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
-    "1234567890123456789012345678901234567890"
-        "1234567890123456789012345678901234567890",
+    { "" },
+    { "a" },
+    { "abc" },
+    { "message digest" },
+    { "abcdefghijklmnopqrstuvwxyz" },
+    { "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq" },
+    { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" },
+    { "12345678901234567890123456789012345678901234567890123456789012"
+      "345678901234567890" },
+};
+
+static const size_t ripemd160_test_strlen[TESTS] =
+{
+    0, 1, 3, 14, 26, 56, 62, 80
 };
 
 static const unsigned char ripemd160_test_md[TESTS][20] =
@@ -430,7 +473,7 @@
  */
 int mbedtls_ripemd160_self_test( int verbose )
 {
-    int i;
+    int i, ret = 0;
     unsigned char output[20];
 
     memset( output, 0, sizeof output );
@@ -440,16 +483,15 @@
         if( verbose != 0 )
             mbedtls_printf( "  RIPEMD-160 test #%d: ", i + 1 );
 
-        mbedtls_ripemd160( (const unsigned char *) ripemd160_test_input[i],
-                   strlen( ripemd160_test_input[i] ),
-                   output );
+        ret = mbedtls_ripemd160_ret( ripemd160_test_str[i],
+                                     ripemd160_test_strlen[i], output );
+        if( ret != 0 )
+            goto fail;
 
         if( memcmp( output, ripemd160_test_md[i], 20 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
+            ret = 1;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -460,6 +502,12 @@
         mbedtls_printf( "\n" );
 
     return( 0 );
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
+    return( ret );
 }
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/library/rsa.c b/library/rsa.c
index 7b37397..6526978 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -942,7 +942,7 @@
  * \param slen      length of the source buffer
  * \param md_ctx    message digest context to use
  */
-static void mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
+static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src,
                       size_t slen, mbedtls_md_context_t *md_ctx )
 {
     unsigned char mask[MBEDTLS_MD_MAX_SIZE];
@@ -950,6 +950,7 @@
     unsigned char *p;
     unsigned int hlen;
     size_t i, use_len;
+    int ret = 0;
 
     memset( mask, 0, MBEDTLS_MD_MAX_SIZE );
     memset( counter, 0, 4 );
@@ -965,10 +966,14 @@
         if( dlen < hlen )
             use_len = dlen;
 
-        mbedtls_md_starts( md_ctx );
-        mbedtls_md_update( md_ctx, src, slen );
-        mbedtls_md_update( md_ctx, counter, 4 );
-        mbedtls_md_finish( md_ctx, mask );
+        if( ( ret = mbedtls_md_starts( md_ctx ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_md_update( md_ctx, src, slen ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_md_update( md_ctx, counter, 4 ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_md_finish( md_ctx, mask ) ) != 0 )
+            goto exit;
 
         for( i = 0; i < use_len; ++i )
             *p++ ^= mask[i];
@@ -978,7 +983,10 @@
         dlen -= use_len;
     }
 
+exit:
     mbedtls_zeroize( mask, sizeof( mask ) );
+
+    return( ret );
 }
 #endif /* MBEDTLS_PKCS1_V21 */
 
@@ -1030,7 +1038,8 @@
     p += hlen;
 
     /* Construct DB */
-    mbedtls_md( md_info, label, label_len, p );
+    if( ( ret = mbedtls_md( md_info, label, label_len, p ) ) != 0 )
+        return( ret );
     p += hlen;
     p += olen - 2 * hlen - 2 - ilen;
     *p++ = 1;
@@ -1038,21 +1047,24 @@
 
     mbedtls_md_init( &md_ctx );
     if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
-    {
-        mbedtls_md_free( &md_ctx );
-        return( ret );
-    }
+        goto exit;
 
     /* maskedDB: Apply dbMask to DB */
-    mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen,
-               &md_ctx );
+    if( ( ret = mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen,
+                          &md_ctx ) ) != 0 )
+        goto exit;
 
     /* maskedSeed: Apply seedMask to seed */
-    mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,
-               &md_ctx );
+    if( ( ret = mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,
+                          &md_ctx ) ) != 0 )
+        goto exit;
 
+exit:
     mbedtls_md_free( &md_ctx );
 
+    if( ret != 0 )
+        return( ret );
+
     return( ( mode == MBEDTLS_RSA_PUBLIC )
             ? mbedtls_rsa_public(  ctx, output, output )
             : mbedtls_rsa_private( ctx, f_rng, p_rng, output, output ) );
@@ -1219,20 +1231,23 @@
         goto cleanup;
     }
 
-
-    /* Generate lHash */
-    mbedtls_md( md_info, label, label_len, lhash );
-
     /* seed: Apply seedMask to maskedSeed */
-    mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,
-               &md_ctx );
-
+    if( ( ret = mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,
+                          &md_ctx ) ) != 0 ||
     /* DB: Apply dbMask to maskedDB */
-    mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,
-               &md_ctx );
+        ( ret = mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,
+                          &md_ctx ) ) != 0 )
+    {
+        mbedtls_md_free( &md_ctx );
+        goto cleanup;
+    }
 
     mbedtls_md_free( &md_ctx );
 
+    /* Generate lHash */
+    if( ( ret = mbedtls_md( md_info, label, label_len, lhash ) ) != 0 )
+        goto cleanup;
+
     /*
      * Check contents, in "constant-time"
      */
@@ -1483,28 +1498,28 @@
 
     mbedtls_md_init( &md_ctx );
     if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
-    {
-        mbedtls_md_free( &md_ctx );
-        /* No need to zeroize salt: we didn't use it. */
-        return( ret );
-    }
+        goto exit;
 
     /* Generate H = Hash( M' ) */
-    mbedtls_md_starts( &md_ctx );
-    mbedtls_md_update( &md_ctx, p, 8 );
-    mbedtls_md_update( &md_ctx, hash, hashlen );
-    mbedtls_md_update( &md_ctx, salt, slen );
-    mbedtls_md_finish( &md_ctx, p );
-    mbedtls_zeroize( salt, sizeof( salt ) );
+    if( ( ret = mbedtls_md_starts( &md_ctx ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md_update( &md_ctx, p, 8 ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md_update( &md_ctx, hash, hashlen ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md_update( &md_ctx, salt, slen ) ) != 0 )
+        goto exit;
+    if( ( ret = mbedtls_md_finish( &md_ctx, p ) ) != 0 )
+        goto exit;
 
     /* Compensate for boundary condition when applying mask */
     if( msb % 8 == 0 )
         offset = 1;
 
     /* maskedDB: Apply dbMask to DB */
-    mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen, &md_ctx );
-
-    mbedtls_md_free( &md_ctx );
+    if( ( ret = mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen,
+                          &md_ctx ) ) != 0 )
+        goto exit;
 
     msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
     sig[0] &= 0xFF >> ( olen * 8 - msb );
@@ -1512,6 +1527,14 @@
     p += hlen;
     *p++ = 0xBC;
 
+    mbedtls_zeroize( salt, sizeof( salt ) );
+
+exit:
+    mbedtls_md_free( &md_ctx );
+
+    if( ret != 0 )
+        return( ret );
+
     return( ( mode == MBEDTLS_RSA_PUBLIC )
             ? mbedtls_rsa_public(  ctx, sig, sig )
             : mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig ) );
@@ -1842,12 +1865,11 @@
 
     mbedtls_md_init( &md_ctx );
     if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
-    {
-        mbedtls_md_free( &md_ctx );
-        return( ret );
-    }
+        goto exit;
 
-    mgf_mask( p, siglen - hlen - 1, hash_start, hlen, &md_ctx );
+    ret = mgf_mask( p, siglen - hlen - 1, hash_start, hlen, &md_ctx );
+    if( ret != 0 )
+        goto exit;
 
     buf[0] &= 0xFF >> ( siglen * 8 - msb );
 
@@ -1856,8 +1878,8 @@
 
     if( *p++ != 0x01 )
     {
-        mbedtls_md_free( &md_ctx );
-        return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+        ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
+        goto exit;
     }
 
     observed_salt_len = hash_start - p;
@@ -1865,25 +1887,39 @@
     if( expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY &&
         observed_salt_len != (size_t) expected_salt_len )
     {
-        mbedtls_md_free( &md_ctx );
-        return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+        ret = MBEDTLS_ERR_RSA_INVALID_PADDING;
+        goto exit;
     }
 
     /*
      * Generate H = Hash( M' )
      */
-    mbedtls_md_starts( &md_ctx );
-    mbedtls_md_update( &md_ctx, zeros, 8 );
-    mbedtls_md_update( &md_ctx, hash, hashlen );
-    mbedtls_md_update( &md_ctx, p, observed_salt_len );
-    mbedtls_md_finish( &md_ctx, result );
+    ret = mbedtls_md_starts( &md_ctx );
+    if ( ret != 0 )
+        goto exit;
+    ret = mbedtls_md_update( &md_ctx, zeros, 8 );
+    if ( ret != 0 )
+        goto exit;
+    ret = mbedtls_md_update( &md_ctx, hash, hashlen );
+    if ( ret != 0 )
+        goto exit;
+    ret = mbedtls_md_update( &md_ctx, p, observed_salt_len );
+    if ( ret != 0 )
+        goto exit;
+    ret = mbedtls_md_finish( &md_ctx, result );
+    if ( ret != 0 )
+        goto exit;
 
+    if( memcmp( hash_start, result, hlen ) != 0 )
+    {
+        ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;
+        goto exit;
+    }
+
+exit:
     mbedtls_md_free( &md_ctx );
 
-    if( memcmp( hash_start, result, hlen ) == 0 )
-        return( 0 );
-    else
-        return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+    return( ret );
 }
 
 /*
@@ -2232,7 +2268,13 @@
     if( verbose != 0 )
         mbedtls_printf( "  PKCS#1 data sign  : " );
 
-    mbedtls_sha1( rsa_plaintext, PT_LEN, sha1sum );
+    if( mbedtls_sha1_ret( rsa_plaintext, PT_LEN, sha1sum ) != 0 )
+    {
+        if( verbose != 0 )
+            mbedtls_printf( "failed\n" );
+
+        return( 1 );
+    }
 
     if( mbedtls_rsa_pkcs1_sign( &rsa, myrand, NULL,
                                 MBEDTLS_RSA_PRIVATE, MBEDTLS_MD_SHA1, 0,
diff --git a/library/sha1.c b/library/sha1.c
index 2ccf2a2..8432eba 100644
--- a/library/sha1.c
+++ b/library/sha1.c
@@ -97,7 +97,7 @@
 /*
  * SHA-1 context setup
  */
-void mbedtls_sha1_starts( mbedtls_sha1_context *ctx )
+int mbedtls_sha1_starts_ret( mbedtls_sha1_context *ctx )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -107,10 +107,13 @@
     ctx->state[2] = 0x98BADCFE;
     ctx->state[3] = 0x10325476;
     ctx->state[4] = 0xC3D2E1F0;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_SHA1_PROCESS_ALT)
-void mbedtls_sha1_process( mbedtls_sha1_context *ctx, const unsigned char data[64] )
+int mbedtls_internal_sha1_process( mbedtls_sha1_context *ctx,
+                                   const unsigned char data[64] )
 {
     uint32_t temp, W[16], A, B, C, D, E;
 
@@ -264,19 +267,24 @@
     ctx->state[2] += C;
     ctx->state[3] += D;
     ctx->state[4] += E;
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_SHA1_PROCESS_ALT */
 
 /*
  * SHA-1 process buffer
  */
-void mbedtls_sha1_update( mbedtls_sha1_context *ctx, const unsigned char *input, size_t ilen )
+int mbedtls_sha1_update_ret( mbedtls_sha1_context *ctx,
+                             const unsigned char *input,
+                             size_t ilen )
 {
+    int ret;
     size_t fill;
     uint32_t left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = ctx->total[0] & 0x3F;
     fill = 64 - left;
@@ -290,7 +298,10 @@
     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
-        mbedtls_sha1_process( ctx, ctx->buffer );
+
+        if( ( ret = mbedtls_internal_sha1_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -298,13 +309,17 @@
 
     while( ilen >= 64 )
     {
-        mbedtls_sha1_process( ctx, input );
+        if( ( ret = mbedtls_internal_sha1_process( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 64;
         ilen  -= 64;
     }
 
     if( ilen > 0 )
         memcpy( (void *) (ctx->buffer + left), input, ilen );
+
+    return( 0 );
 }
 
 static const unsigned char sha1_padding[64] =
@@ -318,8 +333,10 @@
 /*
  * SHA-1 final digest
  */
-void mbedtls_sha1_finish( mbedtls_sha1_context *ctx, unsigned char output[20] )
+int mbedtls_sha1_finish_ret( mbedtls_sha1_context *ctx,
+                             unsigned char output[20] )
 {
+    int ret;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -334,14 +351,18 @@
     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
 
-    mbedtls_sha1_update( ctx, sha1_padding, padn );
-    mbedtls_sha1_update( ctx, msglen, 8 );
+    if( ( ret = mbedtls_sha1_update_ret( ctx, sha1_padding, padn ) ) != 0 )
+        return( ret );
+    if( ( ret = mbedtls_sha1_update_ret( ctx, msglen, 8 ) ) != 0 )
+        return( ret );
 
     PUT_UINT32_BE( ctx->state[0], output,  0 );
     PUT_UINT32_BE( ctx->state[1], output,  4 );
     PUT_UINT32_BE( ctx->state[2], output,  8 );
     PUT_UINT32_BE( ctx->state[3], output, 12 );
     PUT_UINT32_BE( ctx->state[4], output, 16 );
+
+    return( 0 );
 }
 
 #endif /* !MBEDTLS_SHA1_ALT */
@@ -349,15 +370,28 @@
 /*
  * output = SHA-1( input buffer )
  */
-void mbedtls_sha1( const unsigned char *input, size_t ilen, unsigned char output[20] )
+int mbedtls_sha1_ret( const unsigned char *input,
+                      size_t ilen,
+                      unsigned char output[20] )
 {
+    int ret;
     mbedtls_sha1_context ctx;
 
     mbedtls_sha1_init( &ctx );
-    mbedtls_sha1_starts( &ctx );
-    mbedtls_sha1_update( &ctx, input, ilen );
-    mbedtls_sha1_finish( &ctx, output );
+
+    if( ( ret = mbedtls_sha1_starts_ret( &ctx ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_sha1_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_sha1_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_sha1_free( &ctx );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -371,7 +405,7 @@
     { "" }
 };
 
-static const int sha1_test_buflen[3] =
+static const size_t sha1_test_buflen[3] =
 {
     3, 56, 1000
 };
@@ -406,28 +440,35 @@
         if( verbose != 0 )
             mbedtls_printf( "  SHA-1 test #%d: ", i + 1 );
 
-        mbedtls_sha1_starts( &ctx );
+        if( ( ret = mbedtls_sha1_starts_ret( &ctx ) ) != 0 )
+            goto fail;
 
         if( i == 2 )
         {
             memset( buf, 'a', buflen = 1000 );
 
             for( j = 0; j < 1000; j++ )
-                mbedtls_sha1_update( &ctx, buf, buflen );
+            {
+                ret = mbedtls_sha1_update_ret( &ctx, buf, buflen );
+                if( ret != 0 )
+                    goto fail;
+            }
         }
         else
-            mbedtls_sha1_update( &ctx, sha1_test_buf[i],
-                               sha1_test_buflen[i] );
+        {
+            ret = mbedtls_sha1_update_ret( &ctx, sha1_test_buf[i],
+                                           sha1_test_buflen[i] );
+            if( ret != 0 )
+                goto fail;
+        }
 
-        mbedtls_sha1_finish( &ctx, sha1sum );
+        if( ( ret = mbedtls_sha1_finish_ret( &ctx, sha1sum ) ) != 0 )
+            goto fail;
 
         if( memcmp( sha1sum, sha1_test_sum[i], 20 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
             ret = 1;
-            goto exit;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -437,6 +478,12 @@
     if( verbose != 0 )
         mbedtls_printf( "\n" );
 
+    goto exit;
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
 exit:
     mbedtls_sha1_free( &ctx );
 
diff --git a/library/sha256.c b/library/sha256.c
index ad25d38..abcd64d 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -100,7 +100,7 @@
 /*
  * SHA-256 context setup
  */
-void mbedtls_sha256_starts( mbedtls_sha256_context *ctx, int is224 )
+int mbedtls_sha256_starts_ret( mbedtls_sha256_context *ctx, int is224 )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -131,6 +131,8 @@
     }
 
     ctx->is224 = is224;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_SHA256_PROCESS_ALT)
@@ -179,7 +181,8 @@
     d += temp1; h = temp1 + temp2;              \
 }
 
-void mbedtls_sha256_process( mbedtls_sha256_context *ctx, const unsigned char data[64] )
+int mbedtls_internal_sha256_process( mbedtls_sha256_context *ctx,
+                                const unsigned char data[64] )
 {
     uint32_t temp1, temp2, W[64];
     uint32_t A[8];
@@ -232,20 +235,24 @@
 
     for( i = 0; i < 8; i++ )
         ctx->state[i] += A[i];
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_SHA256_PROCESS_ALT */
 
 /*
  * SHA-256 process buffer
  */
-void mbedtls_sha256_update( mbedtls_sha256_context *ctx, const unsigned char *input,
-                    size_t ilen )
+int mbedtls_sha256_update_ret( mbedtls_sha256_context *ctx,
+                               const unsigned char *input,
+                               size_t ilen )
 {
+    int ret;
     size_t fill;
     uint32_t left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = ctx->total[0] & 0x3F;
     fill = 64 - left;
@@ -259,7 +266,10 @@
     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
-        mbedtls_sha256_process( ctx, ctx->buffer );
+
+        if( ( ret = mbedtls_internal_sha256_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -267,13 +277,17 @@
 
     while( ilen >= 64 )
     {
-        mbedtls_sha256_process( ctx, input );
+        if( ( ret = mbedtls_internal_sha256_process( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 64;
         ilen  -= 64;
     }
 
     if( ilen > 0 )
         memcpy( (void *) (ctx->buffer + left), input, ilen );
+
+    return( 0 );
 }
 
 static const unsigned char sha256_padding[64] =
@@ -287,8 +301,10 @@
 /*
  * SHA-256 final digest
  */
-void mbedtls_sha256_finish( mbedtls_sha256_context *ctx, unsigned char output[32] )
+int mbedtls_sha256_finish_ret( mbedtls_sha256_context *ctx,
+                               unsigned char output[32] )
 {
+    int ret;
     uint32_t last, padn;
     uint32_t high, low;
     unsigned char msglen[8];
@@ -303,8 +319,11 @@
     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
 
-    mbedtls_sha256_update( ctx, sha256_padding, padn );
-    mbedtls_sha256_update( ctx, msglen, 8 );
+    if( ( ret = mbedtls_sha256_update_ret( ctx, sha256_padding, padn ) ) != 0 )
+        return( ret );
+
+    if( ( ret = mbedtls_sha256_update_ret( ctx, msglen, 8 ) ) != 0 )
+        return( ret );
 
     PUT_UINT32_BE( ctx->state[0], output,  0 );
     PUT_UINT32_BE( ctx->state[1], output,  4 );
@@ -316,6 +335,8 @@
 
     if( ctx->is224 == 0 )
         PUT_UINT32_BE( ctx->state[7], output, 28 );
+
+    return( 0 );
 }
 
 #endif /* !MBEDTLS_SHA256_ALT */
@@ -323,16 +344,29 @@
 /*
  * output = SHA-256( input buffer )
  */
-void mbedtls_sha256( const unsigned char *input, size_t ilen,
-             unsigned char output[32], int is224 )
+int mbedtls_sha256_ret( const unsigned char *input,
+                        size_t ilen,
+                        unsigned char output[32],
+                        int is224 )
 {
+    int ret;
     mbedtls_sha256_context ctx;
 
     mbedtls_sha256_init( &ctx );
-    mbedtls_sha256_starts( &ctx, is224 );
-    mbedtls_sha256_update( &ctx, input, ilen );
-    mbedtls_sha256_finish( &ctx, output );
+
+    if( ( ret = mbedtls_sha256_starts_ret( &ctx, is224 ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_sha256_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_sha256_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_sha256_free( &ctx );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -346,7 +380,7 @@
     { "" }
 };
 
-static const int sha256_test_buflen[3] =
+static const size_t sha256_test_buflen[3] =
 {
     3, 56, 1000
 };
@@ -415,28 +449,37 @@
         if( verbose != 0 )
             mbedtls_printf( "  SHA-%d test #%d: ", 256 - k * 32, j + 1 );
 
-        mbedtls_sha256_starts( &ctx, k );
+        if( ( ret = mbedtls_sha256_starts_ret( &ctx, k ) ) != 0 )
+            goto fail;
 
         if( j == 2 )
         {
             memset( buf, 'a', buflen = 1000 );
 
             for( j = 0; j < 1000; j++ )
-                mbedtls_sha256_update( &ctx, buf, buflen );
+            {
+                ret = mbedtls_sha256_update_ret( &ctx, buf, buflen );
+                if( ret != 0 )
+                    goto fail;
+            }
+
         }
         else
-            mbedtls_sha256_update( &ctx, sha256_test_buf[j],
-                                 sha256_test_buflen[j] );
+        {
+            ret = mbedtls_sha256_update_ret( &ctx, sha256_test_buf[j],
+                                             sha256_test_buflen[j] );
+            if( ret != 0 )
+                 goto fail;
+        }
 
-        mbedtls_sha256_finish( &ctx, sha256sum );
+        if( ( ret = mbedtls_sha256_finish_ret( &ctx, sha256sum ) ) != 0 )
+            goto fail;
+
 
         if( memcmp( sha256sum, sha256_test_sum[i], 32 - k * 4 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
             ret = 1;
-            goto exit;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -446,6 +489,12 @@
     if( verbose != 0 )
         mbedtls_printf( "\n" );
 
+    goto exit;
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
 exit:
     mbedtls_sha256_free( &ctx );
     mbedtls_free( buf );
diff --git a/library/sha512.c b/library/sha512.c
index 724522a..c99b6da 100644
--- a/library/sha512.c
+++ b/library/sha512.c
@@ -114,7 +114,7 @@
 /*
  * SHA-512 context setup
  */
-void mbedtls_sha512_starts( mbedtls_sha512_context *ctx, int is384 )
+int mbedtls_sha512_starts_ret( mbedtls_sha512_context *ctx, int is384 )
 {
     ctx->total[0] = 0;
     ctx->total[1] = 0;
@@ -145,6 +145,8 @@
     }
 
     ctx->is384 = is384;
+
+    return( 0 );
 }
 
 #if !defined(MBEDTLS_SHA512_PROCESS_ALT)
@@ -196,7 +198,8 @@
     UL64(0x5FCB6FAB3AD6FAEC),  UL64(0x6C44198C4A475817)
 };
 
-void mbedtls_sha512_process( mbedtls_sha512_context *ctx, const unsigned char data[128] )
+int mbedtls_internal_sha512_process( mbedtls_sha512_context *ctx,
+                                     const unsigned char data[128] )
 {
     int i;
     uint64_t temp1, temp2, W[80];
@@ -263,20 +266,24 @@
     ctx->state[5] += F;
     ctx->state[6] += G;
     ctx->state[7] += H;
+
+    return( 0 );
 }
 #endif /* !MBEDTLS_SHA512_PROCESS_ALT */
 
 /*
  * SHA-512 process buffer
  */
-void mbedtls_sha512_update( mbedtls_sha512_context *ctx, const unsigned char *input,
-                    size_t ilen )
+int mbedtls_sha512_update_ret( mbedtls_sha512_context *ctx,
+                               const unsigned char *input,
+                               size_t ilen )
 {
+    int ret;
     size_t fill;
     unsigned int left;
 
     if( ilen == 0 )
-        return;
+        return( 0 );
 
     left = (unsigned int) (ctx->total[0] & 0x7F);
     fill = 128 - left;
@@ -289,7 +296,10 @@
     if( left && ilen >= fill )
     {
         memcpy( (void *) (ctx->buffer + left), input, fill );
-        mbedtls_sha512_process( ctx, ctx->buffer );
+
+        if( ( ret = mbedtls_internal_sha512_process( ctx, ctx->buffer ) ) != 0 )
+            return( ret );
+
         input += fill;
         ilen  -= fill;
         left = 0;
@@ -297,13 +307,17 @@
 
     while( ilen >= 128 )
     {
-        mbedtls_sha512_process( ctx, input );
+        if( ( ret = mbedtls_internal_sha512_process( ctx, input ) ) != 0 )
+            return( ret );
+
         input += 128;
         ilen  -= 128;
     }
 
     if( ilen > 0 )
         memcpy( (void *) (ctx->buffer + left), input, ilen );
+
+    return( 0 );
 }
 
 static const unsigned char sha512_padding[128] =
@@ -321,8 +335,10 @@
 /*
  * SHA-512 final digest
  */
-void mbedtls_sha512_finish( mbedtls_sha512_context *ctx, unsigned char output[64] )
+int mbedtls_sha512_finish_ret( mbedtls_sha512_context *ctx,
+                               unsigned char output[64] )
 {
+    int ret;
     size_t last, padn;
     uint64_t high, low;
     unsigned char msglen[16];
@@ -337,8 +353,11 @@
     last = (size_t)( ctx->total[0] & 0x7F );
     padn = ( last < 112 ) ? ( 112 - last ) : ( 240 - last );
 
-    mbedtls_sha512_update( ctx, sha512_padding, padn );
-    mbedtls_sha512_update( ctx, msglen, 16 );
+    if( ( ret = mbedtls_sha512_update_ret( ctx, sha512_padding, padn ) ) != 0 )
+            return( ret );
+
+    if( ( ret = mbedtls_sha512_update_ret( ctx, msglen, 16 ) ) != 0 )
+            return( ret );
 
     PUT_UINT64_BE( ctx->state[0], output,  0 );
     PUT_UINT64_BE( ctx->state[1], output,  8 );
@@ -352,6 +371,8 @@
         PUT_UINT64_BE( ctx->state[6], output, 48 );
         PUT_UINT64_BE( ctx->state[7], output, 56 );
     }
+
+    return( 0 );
 }
 
 #endif /* !MBEDTLS_SHA512_ALT */
@@ -359,16 +380,29 @@
 /*
  * output = SHA-512( input buffer )
  */
-void mbedtls_sha512( const unsigned char *input, size_t ilen,
-             unsigned char output[64], int is384 )
+int mbedtls_sha512_ret( const unsigned char *input,
+                    size_t ilen,
+                    unsigned char output[64],
+                    int is384 )
 {
+    int ret;
     mbedtls_sha512_context ctx;
 
     mbedtls_sha512_init( &ctx );
-    mbedtls_sha512_starts( &ctx, is384 );
-    mbedtls_sha512_update( &ctx, input, ilen );
-    mbedtls_sha512_finish( &ctx, output );
+
+    if( ( ret = mbedtls_sha512_starts_ret( &ctx, is384 ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_sha512_update_ret( &ctx, input, ilen ) ) != 0 )
+        goto exit;
+
+    if( ( ret = mbedtls_sha512_finish_ret( &ctx, output ) ) != 0 )
+        goto exit;
+
+exit:
     mbedtls_sha512_free( &ctx );
+
+    return( ret );
 }
 
 #if defined(MBEDTLS_SELF_TEST)
@@ -384,7 +418,7 @@
     { "" }
 };
 
-static const int sha512_test_buflen[3] =
+static const size_t sha512_test_buflen[3] =
 {
     3, 112, 1000
 };
@@ -471,28 +505,35 @@
         if( verbose != 0 )
             mbedtls_printf( "  SHA-%d test #%d: ", 512 - k * 128, j + 1 );
 
-        mbedtls_sha512_starts( &ctx, k );
+        if( ( ret = mbedtls_sha512_starts_ret( &ctx, k ) ) != 0 )
+            goto fail;
 
         if( j == 2 )
         {
             memset( buf, 'a', buflen = 1000 );
 
             for( j = 0; j < 1000; j++ )
-                mbedtls_sha512_update( &ctx, buf, buflen );
+            {
+                ret = mbedtls_sha512_update_ret( &ctx, buf, buflen );
+                if( ret != 0 )
+                    goto fail;
+            }
         }
         else
-            mbedtls_sha512_update( &ctx, sha512_test_buf[j],
-                                 sha512_test_buflen[j] );
+        {
+            ret = mbedtls_sha512_update_ret( &ctx, sha512_test_buf[j],
+                                             sha512_test_buflen[j] );
+            if( ret != 0 )
+                goto fail;
+        }
 
-        mbedtls_sha512_finish( &ctx, sha512sum );
+        if( ( ret = mbedtls_sha512_finish_ret( &ctx, sha512sum ) ) != 0 )
+            goto fail;
 
         if( memcmp( sha512sum, sha512_test_sum[i], 64 - k * 16 ) != 0 )
         {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
             ret = 1;
-            goto exit;
+            goto fail;
         }
 
         if( verbose != 0 )
@@ -502,6 +543,12 @@
     if( verbose != 0 )
         mbedtls_printf( "\n" );
 
+    goto exit;
+
+fail:
+    if( verbose != 0 )
+        mbedtls_printf( "failed\n" );
+
 exit:
     mbedtls_sha512_free( &ctx );
     mbedtls_free( buf );
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 554348f..2534346 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2498,39 +2498,11 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_1)
         if( md_alg == MBEDTLS_MD_NONE )
         {
-            mbedtls_md5_context mbedtls_md5;
-            mbedtls_sha1_context mbedtls_sha1;
-
-            mbedtls_md5_init(  &mbedtls_md5  );
-            mbedtls_sha1_init( &mbedtls_sha1 );
-
             hashlen = 36;
-
-            /*
-             * digitally-signed struct {
-             *     opaque md5_hash[16];
-             *     opaque sha_hash[20];
-             * };
-             *
-             * md5_hash
-             *     MD5(ClientHello.random + ServerHello.random
-             *                            + ServerParams);
-             * sha_hash
-             *     SHA(ClientHello.random + ServerHello.random
-             *                            + ServerParams);
-             */
-            mbedtls_md5_starts( &mbedtls_md5 );
-            mbedtls_md5_update( &mbedtls_md5, ssl->handshake->randbytes, 64 );
-            mbedtls_md5_update( &mbedtls_md5, params, params_len );
-            mbedtls_md5_finish( &mbedtls_md5, hash );
-
-            mbedtls_sha1_starts( &mbedtls_sha1 );
-            mbedtls_sha1_update( &mbedtls_sha1, ssl->handshake->randbytes, 64 );
-            mbedtls_sha1_update( &mbedtls_sha1, params, params_len );
-            mbedtls_sha1_finish( &mbedtls_sha1, hash + 16 );
-
-            mbedtls_md5_free(  &mbedtls_md5  );
-            mbedtls_sha1_free( &mbedtls_sha1 );
+            ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash, params,
+                                                           params_len );
+            if( ret != 0 )
+                return( ret );
         }
         else
 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
@@ -2539,34 +2511,12 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_2)
         if( md_alg != MBEDTLS_MD_NONE )
         {
-            mbedtls_md_context_t ctx;
-
-            mbedtls_md_init( &ctx );
-
             /* Info from md_alg will be used instead */
             hashlen = 0;
-
-            /*
-             * digitally-signed struct {
-             *     opaque client_random[32];
-             *     opaque server_random[32];
-             *     ServerDHParams params;
-             * };
-             */
-            if( ( ret = mbedtls_md_setup( &ctx,
-                                     mbedtls_md_info_from_type( md_alg ), 0 ) ) != 0 )
-            {
-                MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_setup", ret );
-                mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                                                MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
+            ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash, params,
+                                                          params_len, md_alg );
+            if( ret != 0 )
                 return( ret );
-            }
-
-            mbedtls_md_starts( &ctx );
-            mbedtls_md_update( &ctx, ssl->handshake->randbytes, 64 );
-            mbedtls_md_update( &ctx, params, params_len );
-            mbedtls_md_finish( &ctx, hash );
-            mbedtls_md_free( &ctx );
         }
         else
 #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index dd35887..002c659 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -3101,40 +3101,12 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_1)
         if( md_alg == MBEDTLS_MD_NONE )
         {
-            mbedtls_md5_context mbedtls_md5;
-            mbedtls_sha1_context mbedtls_sha1;
-
-            mbedtls_md5_init(  &mbedtls_md5  );
-            mbedtls_sha1_init( &mbedtls_sha1 );
-
-            /*
-             * digitally-signed struct {
-             *     opaque md5_hash[16];
-             *     opaque sha_hash[20];
-             * };
-             *
-             * md5_hash
-             *     MD5(ClientHello.random + ServerHello.random
-             *                            + ServerParams);
-             * sha_hash
-             *     SHA(ClientHello.random + ServerHello.random
-             *                            + ServerParams);
-             */
-
-            mbedtls_md5_starts( &mbedtls_md5 );
-            mbedtls_md5_update( &mbedtls_md5, ssl->handshake->randbytes,  64 );
-            mbedtls_md5_update( &mbedtls_md5, dig_signed, dig_signed_len );
-            mbedtls_md5_finish( &mbedtls_md5, hash );
-
-            mbedtls_sha1_starts( &mbedtls_sha1 );
-            mbedtls_sha1_update( &mbedtls_sha1, ssl->handshake->randbytes,  64 );
-            mbedtls_sha1_update( &mbedtls_sha1, dig_signed, dig_signed_len );
-            mbedtls_sha1_finish( &mbedtls_sha1, hash + 16 );
-
             hashlen = 36;
-
-            mbedtls_md5_free(  &mbedtls_md5  );
-            mbedtls_sha1_free( &mbedtls_sha1 );
+            ret = mbedtls_ssl_get_key_exchange_md_ssl_tls( ssl, hash,
+                                                           dig_signed,
+                                                           dig_signed_len );
+            if( ret != 0 )
+                return( ret );
         }
         else
 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
@@ -3143,32 +3115,14 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_2)
         if( md_alg != MBEDTLS_MD_NONE )
         {
-            mbedtls_md_context_t ctx;
-            const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_alg );
-
-            mbedtls_md_init( &ctx );
-
             /* Info from md_alg will be used instead */
             hashlen = 0;
-
-            /*
-             * digitally-signed struct {
-             *     opaque client_random[32];
-             *     opaque server_random[32];
-             *     ServerDHParams params;
-             * };
-             */
-            if( ( ret = mbedtls_md_setup( &ctx, md_info, 0 ) ) != 0 )
-            {
-                MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_setup", ret );
+            ret = mbedtls_ssl_get_key_exchange_md_tls1_2( ssl, hash,
+                                                          dig_signed,
+                                                          dig_signed_len,
+                                                          md_alg );
+            if( ret != 0 )
                 return( ret );
-            }
-
-            mbedtls_md_starts( &ctx );
-            mbedtls_md_update( &ctx, ssl->handshake->randbytes, 64 );
-            mbedtls_md_update( &ctx, dig_signed, dig_signed_len );
-            mbedtls_md_finish( &ctx, hash );
-            mbedtls_md_free( &ctx );
         }
         else
 #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index abafe4d..9220dd4 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -221,6 +221,7 @@
                      const unsigned char *random, size_t rlen,
                      unsigned char *dstbuf, size_t dlen )
 {
+    int ret = 0;
     size_t i;
     mbedtls_md5_context md5;
     mbedtls_sha1_context sha1;
@@ -243,25 +244,35 @@
     {
         memset( padding, (unsigned char) ('A' + i), 1 + i );
 
-        mbedtls_sha1_starts( &sha1 );
-        mbedtls_sha1_update( &sha1, padding, 1 + i );
-        mbedtls_sha1_update( &sha1, secret, slen );
-        mbedtls_sha1_update( &sha1, random, rlen );
-        mbedtls_sha1_finish( &sha1, sha1sum );
+        if( ( ret = mbedtls_sha1_starts_ret( &sha1 ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_sha1_update_ret( &sha1, padding, 1 + i ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_sha1_update_ret( &sha1, secret, slen ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_sha1_update_ret( &sha1, random, rlen ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_sha1_finish_ret( &sha1, sha1sum ) ) != 0 )
+            goto exit;
 
-        mbedtls_md5_starts( &md5 );
-        mbedtls_md5_update( &md5, secret, slen );
-        mbedtls_md5_update( &md5, sha1sum, 20 );
-        mbedtls_md5_finish( &md5, dstbuf + i * 16 );
+        if( ( ret = mbedtls_md5_starts_ret( &md5 ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_md5_update_ret( &md5, secret, slen ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_md5_update_ret( &md5, sha1sum, 20 ) ) != 0 )
+            goto exit;
+        if( ( ret = mbedtls_md5_finish_ret( &md5, dstbuf + i * 16 ) ) != 0 )
+            goto exit;
     }
 
+exit:
     mbedtls_md5_free(  &md5  );
     mbedtls_sha1_free( &sha1 );
 
     mbedtls_zeroize( padding, sizeof( padding ) );
     mbedtls_zeroize( sha1sum, sizeof( sha1sum ) );
 
-    return( 0 );
+    return( ret );
 }
 #endif /* MBEDTLS_SSL_PROTO_SSL3 */
 
@@ -978,25 +989,25 @@
     memset( pad_1, 0x36, 48 );
     memset( pad_2, 0x5C, 48 );
 
-    mbedtls_md5_update( &md5, ssl->session_negotiate->master, 48 );
-    mbedtls_md5_update( &md5, pad_1, 48 );
-    mbedtls_md5_finish( &md5, hash );
+    mbedtls_md5_update_ret( &md5, ssl->session_negotiate->master, 48 );
+    mbedtls_md5_update_ret( &md5, pad_1, 48 );
+    mbedtls_md5_finish_ret( &md5, hash );
 
-    mbedtls_md5_starts( &md5 );
-    mbedtls_md5_update( &md5, ssl->session_negotiate->master, 48 );
-    mbedtls_md5_update( &md5, pad_2, 48 );
-    mbedtls_md5_update( &md5, hash,  16 );
-    mbedtls_md5_finish( &md5, hash );
+    mbedtls_md5_starts_ret( &md5 );
+    mbedtls_md5_update_ret( &md5, ssl->session_negotiate->master, 48 );
+    mbedtls_md5_update_ret( &md5, pad_2, 48 );
+    mbedtls_md5_update_ret( &md5, hash,  16 );
+    mbedtls_md5_finish_ret( &md5, hash );
 
-    mbedtls_sha1_update( &sha1, ssl->session_negotiate->master, 48 );
-    mbedtls_sha1_update( &sha1, pad_1, 40 );
-    mbedtls_sha1_finish( &sha1, hash + 16 );
+    mbedtls_sha1_update_ret( &sha1, ssl->session_negotiate->master, 48 );
+    mbedtls_sha1_update_ret( &sha1, pad_1, 40 );
+    mbedtls_sha1_finish_ret( &sha1, hash + 16 );
 
-    mbedtls_sha1_starts( &sha1 );
-    mbedtls_sha1_update( &sha1, ssl->session_negotiate->master, 48 );
-    mbedtls_sha1_update( &sha1, pad_2, 40 );
-    mbedtls_sha1_update( &sha1, hash + 16, 20 );
-    mbedtls_sha1_finish( &sha1, hash + 16 );
+    mbedtls_sha1_starts_ret( &sha1 );
+    mbedtls_sha1_update_ret( &sha1, ssl->session_negotiate->master, 48 );
+    mbedtls_sha1_update_ret( &sha1, pad_2, 40 );
+    mbedtls_sha1_update_ret( &sha1, hash + 16, 20 );
+    mbedtls_sha1_finish_ret( &sha1, hash + 16 );
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, 36 );
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
@@ -1022,8 +1033,8 @@
     mbedtls_md5_clone( &md5, &ssl->handshake->fin_md5 );
     mbedtls_sha1_clone( &sha1, &ssl->handshake->fin_sha1 );
 
-     mbedtls_md5_finish( &md5,  hash );
-    mbedtls_sha1_finish( &sha1, hash + 16 );
+     mbedtls_md5_finish_ret( &md5,  hash );
+    mbedtls_sha1_finish_ret( &sha1, hash + 16 );
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, 36 );
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
@@ -1046,7 +1057,7 @@
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc verify sha256" ) );
 
     mbedtls_sha256_clone( &sha256, &ssl->handshake->fin_sha256 );
-    mbedtls_sha256_finish( &sha256, hash );
+    mbedtls_sha256_finish_ret( &sha256, hash );
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, 32 );
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
@@ -1067,7 +1078,7 @@
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> calc verify sha384" ) );
 
     mbedtls_sha512_clone( &sha512, &ssl->handshake->fin_sha512 );
-    mbedtls_sha512_finish( &sha512, hash );
+    mbedtls_sha512_finish_ret( &sha512, hash );
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "calculated verify result", hash, 48 );
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= calc verify" ) );
@@ -4867,15 +4878,15 @@
 {
 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
     defined(MBEDTLS_SSL_PROTO_TLS1_1)
-     mbedtls_md5_starts( &ssl->handshake->fin_md5  );
-    mbedtls_sha1_starts( &ssl->handshake->fin_sha1 );
+     mbedtls_md5_starts_ret( &ssl->handshake->fin_md5  );
+    mbedtls_sha1_starts_ret( &ssl->handshake->fin_sha1 );
 #endif
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
 #if defined(MBEDTLS_SHA256_C)
-    mbedtls_sha256_starts( &ssl->handshake->fin_sha256, 0 );
+    mbedtls_sha256_starts_ret( &ssl->handshake->fin_sha256, 0 );
 #endif
 #if defined(MBEDTLS_SHA512_C)
-    mbedtls_sha512_starts( &ssl->handshake->fin_sha512, 1 );
+    mbedtls_sha512_starts_ret( &ssl->handshake->fin_sha512, 1 );
 #endif
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
 }
@@ -4885,15 +4896,15 @@
 {
 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
     defined(MBEDTLS_SSL_PROTO_TLS1_1)
-     mbedtls_md5_update( &ssl->handshake->fin_md5 , buf, len );
-    mbedtls_sha1_update( &ssl->handshake->fin_sha1, buf, len );
+     mbedtls_md5_update_ret( &ssl->handshake->fin_md5 , buf, len );
+    mbedtls_sha1_update_ret( &ssl->handshake->fin_sha1, buf, len );
 #endif
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
 #if defined(MBEDTLS_SHA256_C)
-    mbedtls_sha256_update( &ssl->handshake->fin_sha256, buf, len );
+    mbedtls_sha256_update_ret( &ssl->handshake->fin_sha256, buf, len );
 #endif
 #if defined(MBEDTLS_SHA512_C)
-    mbedtls_sha512_update( &ssl->handshake->fin_sha512, buf, len );
+    mbedtls_sha512_update_ret( &ssl->handshake->fin_sha512, buf, len );
 #endif
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
 }
@@ -4903,8 +4914,8 @@
 static void ssl_update_checksum_md5sha1( mbedtls_ssl_context *ssl,
                                          const unsigned char *buf, size_t len )
 {
-     mbedtls_md5_update( &ssl->handshake->fin_md5 , buf, len );
-    mbedtls_sha1_update( &ssl->handshake->fin_sha1, buf, len );
+     mbedtls_md5_update_ret( &ssl->handshake->fin_md5 , buf, len );
+    mbedtls_sha1_update_ret( &ssl->handshake->fin_sha1, buf, len );
 }
 #endif
 
@@ -4913,7 +4924,7 @@
 static void ssl_update_checksum_sha256( mbedtls_ssl_context *ssl,
                                         const unsigned char *buf, size_t len )
 {
-    mbedtls_sha256_update( &ssl->handshake->fin_sha256, buf, len );
+    mbedtls_sha256_update_ret( &ssl->handshake->fin_sha256, buf, len );
 }
 #endif
 
@@ -4921,7 +4932,7 @@
 static void ssl_update_checksum_sha384( mbedtls_ssl_context *ssl,
                                         const unsigned char *buf, size_t len )
 {
-    mbedtls_sha512_update( &ssl->handshake->fin_sha512, buf, len );
+    mbedtls_sha512_update_ret( &ssl->handshake->fin_sha512, buf, len );
 }
 #endif
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
@@ -4974,29 +4985,29 @@
 
     memset( padbuf, 0x36, 48 );
 
-    mbedtls_md5_update( &md5, (const unsigned char *) sender, 4 );
-    mbedtls_md5_update( &md5, session->master, 48 );
-    mbedtls_md5_update( &md5, padbuf, 48 );
-    mbedtls_md5_finish( &md5, md5sum );
+    mbedtls_md5_update_ret( &md5, (const unsigned char *) sender, 4 );
+    mbedtls_md5_update_ret( &md5, session->master, 48 );
+    mbedtls_md5_update_ret( &md5, padbuf, 48 );
+    mbedtls_md5_finish_ret( &md5, md5sum );
 
-    mbedtls_sha1_update( &sha1, (const unsigned char *) sender, 4 );
-    mbedtls_sha1_update( &sha1, session->master, 48 );
-    mbedtls_sha1_update( &sha1, padbuf, 40 );
-    mbedtls_sha1_finish( &sha1, sha1sum );
+    mbedtls_sha1_update_ret( &sha1, (const unsigned char *) sender, 4 );
+    mbedtls_sha1_update_ret( &sha1, session->master, 48 );
+    mbedtls_sha1_update_ret( &sha1, padbuf, 40 );
+    mbedtls_sha1_finish_ret( &sha1, sha1sum );
 
     memset( padbuf, 0x5C, 48 );
 
-    mbedtls_md5_starts( &md5 );
-    mbedtls_md5_update( &md5, session->master, 48 );
-    mbedtls_md5_update( &md5, padbuf, 48 );
-    mbedtls_md5_update( &md5, md5sum, 16 );
-    mbedtls_md5_finish( &md5, buf );
+    mbedtls_md5_starts_ret( &md5 );
+    mbedtls_md5_update_ret( &md5, session->master, 48 );
+    mbedtls_md5_update_ret( &md5, padbuf, 48 );
+    mbedtls_md5_update_ret( &md5, md5sum, 16 );
+    mbedtls_md5_finish_ret( &md5, buf );
 
-    mbedtls_sha1_starts( &sha1 );
-    mbedtls_sha1_update( &sha1, session->master, 48 );
-    mbedtls_sha1_update( &sha1, padbuf , 40 );
-    mbedtls_sha1_update( &sha1, sha1sum, 20 );
-    mbedtls_sha1_finish( &sha1, buf + 16 );
+    mbedtls_sha1_starts_ret( &sha1 );
+    mbedtls_sha1_update_ret( &sha1, session->master, 48 );
+    mbedtls_sha1_update_ret( &sha1, padbuf , 40 );
+    mbedtls_sha1_update_ret( &sha1, sha1sum, 20 );
+    mbedtls_sha1_finish_ret( &sha1, buf + 16 );
 
     MBEDTLS_SSL_DEBUG_BUF( 3, "calc finished result", buf, 36 );
 
@@ -5053,8 +5064,8 @@
              ? "client finished"
              : "server finished";
 
-    mbedtls_md5_finish(  &md5, padbuf );
-    mbedtls_sha1_finish( &sha1, padbuf + 16 );
+    mbedtls_md5_finish_ret(  &md5, padbuf );
+    mbedtls_sha1_finish_ret( &sha1, padbuf + 16 );
 
     ssl->handshake->tls_prf( session->master, 48, sender,
                              padbuf, 36, buf, len );
@@ -5105,7 +5116,7 @@
              ? "client finished"
              : "server finished";
 
-    mbedtls_sha256_finish( &sha256, padbuf );
+    mbedtls_sha256_finish_ret( &sha256, padbuf );
 
     ssl->handshake->tls_prf( session->master, 48, sender,
                              padbuf, 32, buf, len );
@@ -5154,7 +5165,7 @@
              ? "client finished"
              : "server finished";
 
-    mbedtls_sha512_finish( &sha512, padbuf );
+    mbedtls_sha512_finish_ret( &sha512, padbuf );
 
     ssl->handshake->tls_prf( session->master, 48, sender,
                              padbuf, 48, buf, len );
@@ -5468,17 +5479,17 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_1)
      mbedtls_md5_init(   &handshake->fin_md5  );
     mbedtls_sha1_init(   &handshake->fin_sha1 );
-     mbedtls_md5_starts( &handshake->fin_md5  );
-    mbedtls_sha1_starts( &handshake->fin_sha1 );
+     mbedtls_md5_starts_ret( &handshake->fin_md5  );
+    mbedtls_sha1_starts_ret( &handshake->fin_sha1 );
 #endif
 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
 #if defined(MBEDTLS_SHA256_C)
     mbedtls_sha256_init(   &handshake->fin_sha256    );
-    mbedtls_sha256_starts( &handshake->fin_sha256, 0 );
+    mbedtls_sha256_starts_ret( &handshake->fin_sha256, 0 );
 #endif
 #if defined(MBEDTLS_SHA512_C)
     mbedtls_sha512_init(   &handshake->fin_sha512    );
-    mbedtls_sha512_starts( &handshake->fin_sha512, 1 );
+    mbedtls_sha512_starts_ret( &handshake->fin_sha512, 1 );
 #endif
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
 
@@ -8093,4 +8104,148 @@
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
 }
 
+#if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
+    defined(MBEDTLS_SSL_PROTO_TLS1_1)
+int mbedtls_ssl_get_key_exchange_md_ssl_tls( mbedtls_ssl_context *ssl,
+                                        unsigned char *output,
+                                        unsigned char *data, size_t data_len )
+{
+    int ret = 0;
+    mbedtls_md5_context mbedtls_md5;
+    mbedtls_sha1_context mbedtls_sha1;
+
+    mbedtls_md5_init( &mbedtls_md5 );
+    mbedtls_sha1_init( &mbedtls_sha1 );
+
+    /*
+     * digitally-signed struct {
+     *     opaque md5_hash[16];
+     *     opaque sha_hash[20];
+     * };
+     *
+     * md5_hash
+     *     MD5(ClientHello.random + ServerHello.random
+     *                            + ServerParams);
+     * sha_hash
+     *     SHA(ClientHello.random + ServerHello.random
+     *                            + ServerParams);
+     */
+    if( ( ret = mbedtls_md5_starts_ret( &mbedtls_md5 ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md5_starts_ret", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_md5_update_ret( &mbedtls_md5,
+                                        ssl->handshake->randbytes, 64 ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md5_update_ret", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_md5_update_ret( &mbedtls_md5, data, data_len ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md5_update_ret", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_md5_finish_ret( &mbedtls_md5, output ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md5_finish_ret", ret );
+        goto exit;
+    }
+
+    if( ( ret = mbedtls_sha1_starts_ret( &mbedtls_sha1 ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_sha1_starts_ret", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_sha1_update_ret( &mbedtls_sha1,
+                                         ssl->handshake->randbytes, 64 ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_sha1_update_ret", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_sha1_update_ret( &mbedtls_sha1, data,
+                                         data_len ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_sha1_update_ret", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_sha1_finish_ret( &mbedtls_sha1,
+                                         output + 16 ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_sha1_finish_ret", ret );
+        goto exit;
+    }
+
+exit:
+    mbedtls_md5_free( &mbedtls_md5 );
+    mbedtls_sha1_free( &mbedtls_sha1 );
+
+    if( ret != 0 )
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
+
+    return( ret );
+
+}
+#endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
+          MBEDTLS_SSL_PROTO_TLS1_1 */
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
+    defined(MBEDTLS_SSL_PROTO_TLS1_2)
+int mbedtls_ssl_get_key_exchange_md_tls1_2( mbedtls_ssl_context *ssl,
+                                       unsigned char *output,
+                                       unsigned char *data, size_t data_len,
+                                       mbedtls_md_type_t md_alg )
+{
+    int ret = 0;
+    mbedtls_md_context_t ctx;
+    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_alg );
+
+    mbedtls_md_init( &ctx );
+
+    /*
+     * digitally-signed struct {
+     *     opaque client_random[32];
+     *     opaque server_random[32];
+     *     ServerDHParams params;
+     * };
+     */
+    if( ( ret = mbedtls_md_setup( &ctx, md_info, 0 ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_setup", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_md_starts( &ctx ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_starts", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_md_update( &ctx, ssl->handshake->randbytes, 64 ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_update", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_md_update( &ctx, data, data_len ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_update", ret );
+        goto exit;
+    }
+    if( ( ret = mbedtls_md_finish( &ctx, output ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_md_finish", ret );
+        goto exit;
+    }
+
+exit:
+    mbedtls_md_free( &ctx );
+
+    if( ret != 0 )
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
+
+    return( ret );
+}
+#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
+          MBEDTLS_SSL_PROTO_TLS1_2 */
+
 #endif /* MBEDTLS_SSL_TLS_C */
diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index 0af23d7..41dfe87 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -177,8 +177,11 @@
     memset( buf, 0, sizeof(buf) );
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, ctx->subject_key ) );
 
-    mbedtls_sha1( buf + sizeof(buf) - len, len, buf + sizeof(buf) - 20 );
-    c = buf + sizeof(buf) - 20;
+    ret = mbedtls_sha1_ret( buf + sizeof( buf ) - len, len,
+                            buf + sizeof( buf ) - 20 );
+    if( ret != 0 )
+        return( ret );
+    c = buf + sizeof( buf ) - 20;
     len = 20;
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
@@ -199,7 +202,10 @@
     memset( buf, 0, sizeof(buf) );
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, ctx->issuer_key ) );
 
-    mbedtls_sha1( buf + sizeof( buf ) - len, len, buf + sizeof( buf ) - 20 );
+    ret = mbedtls_sha1_ret( buf + sizeof( buf ) - len, len,
+                            buf + sizeof( buf ) - 20 );
+    if( ret != 0 )
+        return( ret );
     c = buf + sizeof( buf ) - 20;
     len = 20;
 
@@ -414,7 +420,11 @@
     /*
      * Make signature
      */
-    mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash );
+    if( ( ret = mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c,
+                            len, hash ) ) != 0 )
+    {
+        return( ret );
+    }
 
     if( ( ret = mbedtls_pk_sign( ctx->issuer_key, ctx->md_alg, hash, 0, sig, &sig_len,
                          f_rng, p_rng ) ) != 0 )