diff --git a/library/base64.c b/library/base64.c
index e0a6f18..3e94548 100644
--- a/library/base64.c
+++ b/library/base64.c
@@ -78,7 +78,7 @@
 /*
  * Encode a buffer into base64 format
  */
-int mbedtls_base64_encode( unsigned char *dst, size_t *dlen,
+int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen,
                    const unsigned char *src, size_t slen )
 {
     size_t i, n;
@@ -87,7 +87,7 @@
 
     if( slen == 0 )
     {
-        *dlen = 0;
+        *olen = 0;
         return( 0 );
     }
 
@@ -100,9 +100,9 @@
         default: break;
     }
 
-    if( *dlen < n + 1 )
+    if( dlen < n + 1 )
     {
-        *dlen = n + 1;
+        *olen = n + 1;
         return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
     }
 
@@ -135,7 +135,7 @@
         *p++ = '=';
     }
 
-    *dlen = p - dst;
+    *olen = p - dst;
     *p = 0;
 
     return( 0 );
@@ -144,7 +144,7 @@
 /*
  * Decode a base64-formatted buffer
  */
-int mbedtls_base64_decode( unsigned char *dst, size_t *dlen,
+int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen,
                    const unsigned char *src, size_t slen )
 {
     size_t i, n;
@@ -195,9 +195,9 @@
     n = ( ( n * 6 ) + 7 ) >> 3;
     n -= j;
 
-    if( dst == NULL || *dlen < n )
+    if( dst == NULL || dlen < n )
     {
-        *dlen = n;
+        *olen = n;
         return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
     }
 
@@ -218,7 +218,7 @@
         }
     }
 
-    *dlen = p - dst;
+    *olen = p - dst;
 
     return( 0 );
 }
@@ -253,10 +253,9 @@
     if( verbose != 0 )
         mbedtls_printf( "  Base64 encoding test: " );
 
-    len = sizeof( buffer );
     src = base64_test_dec;
 
-    if( mbedtls_base64_encode( buffer, &len, src, 64 ) != 0 ||
+    if( mbedtls_base64_encode( buffer, sizeof( buffer ), &len, src, 64 ) != 0 ||
          memcmp( base64_test_enc, buffer, 88 ) != 0 )
     {
         if( verbose != 0 )
@@ -268,10 +267,9 @@
     if( verbose != 0 )
         mbedtls_printf( "passed\n  Base64 decoding test: " );
 
-    len = sizeof( buffer );
     src = base64_test_enc;
 
-    if( mbedtls_base64_decode( buffer, &len, src, 88 ) != 0 ||
+    if( mbedtls_base64_decode( buffer, sizeof( buffer ), &len, src, 88 ) != 0 ||
          memcmp( base64_test_dec, buffer, 64 ) != 0 )
     {
         if( verbose != 0 )
diff --git a/library/pem.c b/library/pem.c
index c1561cb..13fc2df 100644
--- a/library/pem.c
+++ b/library/pem.c
@@ -315,8 +315,7 @@
           ( MBEDTLS_AES_C || MBEDTLS_DES_C ) */
     }
 
-    len = 0;
-    ret = mbedtls_base64_decode( NULL, &len, s1, s2 - s1 );
+    ret = mbedtls_base64_decode( NULL, 0, &len, s1, s2 - s1 );
 
     if( ret == MBEDTLS_ERR_BASE64_INVALID_CHARACTER )
         return( MBEDTLS_ERR_PEM_INVALID_DATA + ret );
@@ -324,7 +323,7 @@
     if( ( buf = mbedtls_calloc( 1, len ) ) == NULL )
         return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
 
-    if( ( ret = mbedtls_base64_decode( buf, &len, s1, s2 - s1 ) ) != 0 )
+    if( ( ret = mbedtls_base64_decode( buf, len, &len, s1, s2 - s1 ) ) != 0 )
     {
         mbedtls_free( buf );
         return( MBEDTLS_ERR_PEM_INVALID_DATA + ret );
@@ -396,9 +395,9 @@
 {
     int ret;
     unsigned char *encode_buf, *c, *p = buf;
-    size_t len = 0, use_len = 0, add_len = 0;
+    size_t len = 0, use_len, add_len = 0;
 
-    mbedtls_base64_encode( NULL, &use_len, der_data, der_len );
+    mbedtls_base64_encode( NULL, 0, &use_len, der_data, der_len );
     add_len = strlen( header ) + strlen( footer ) + ( use_len / 64 ) + 1;
 
     if( use_len + add_len > buf_len )
@@ -410,7 +409,7 @@
     if( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL )
         return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
 
-    if( ( ret = mbedtls_base64_encode( encode_buf, &use_len, der_data,
+    if( ( ret = mbedtls_base64_encode( encode_buf, use_len, &use_len, der_data,
                                der_len ) ) != 0 )
     {
         mbedtls_free( encode_buf );