diff --git a/library/pk.c b/library/pk.c
index e0e8dba..d8bce8f 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -44,13 +44,18 @@
 #include <limits.h>
 #include <stdint.h>
 
+/* Parameter validation macros based on platform_util.h */
+#define PK_VALIDATE_RET( cond )    \
+    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA )
+#define PK_VALIDATE( cond )        \
+    MBEDTLS_INTERNAL_VALIDATE( cond )
+
 /*
  * Initialise a mbedtls_pk_context
  */
 void mbedtls_pk_init( mbedtls_pk_context *ctx )
 {
-    if( ctx == NULL )
-        return;
+    PK_VALIDATE( ctx != NULL );
 
     ctx->pk_info = NULL;
     ctx->pk_ctx = NULL;
@@ -75,6 +80,7 @@
  */
 void mbedtls_pk_restart_init( mbedtls_pk_restart_ctx *ctx )
 {
+    PK_VALIDATE( ctx != NULL );
     ctx->pk_info = NULL;
     ctx->rs_ctx = NULL;
 }
@@ -84,7 +90,8 @@
  */
 void mbedtls_pk_restart_free( mbedtls_pk_restart_ctx *ctx )
 {
-    if( ctx == NULL || ctx->pk_info == NULL ||
+    PK_VALIDATE( ctx != NULL );
+    if( ctx->pk_info == NULL ||
         ctx->pk_info->rs_free_func == NULL )
     {
         return;
@@ -128,7 +135,8 @@
  */
 int mbedtls_pk_setup( mbedtls_pk_context *ctx, const mbedtls_pk_info_t *info )
 {
-    if( ctx == NULL || info == NULL || ctx->pk_info != NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    if( info == NULL || ctx->pk_info != NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ( ctx->pk_ctx = info->ctx_alloc_func() ) == NULL )
@@ -151,7 +159,8 @@
     mbedtls_rsa_alt_context *rsa_alt;
     const mbedtls_pk_info_t *info = &mbedtls_rsa_alt_info;
 
-    if( ctx == NULL || ctx->pk_info != NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    if( ctx->pk_info != NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ( ctx->pk_ctx = info->ctx_alloc_func() ) == NULL )
@@ -175,7 +184,6 @@
  */
 int mbedtls_pk_can_do( const mbedtls_pk_context *ctx, mbedtls_pk_type_t type )
 {
-    /* null or NONE context can't do anything */
     if( ctx == NULL || ctx->pk_info == NULL )
         return( 0 );
 
@@ -232,7 +240,11 @@
                const unsigned char *sig, size_t sig_len,
                mbedtls_pk_restart_ctx *rs_ctx )
 {
-    if( ctx == NULL || ctx->pk_info == NULL ||
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( hash != NULL );
+    PK_VALIDATE_RET( sig != NULL );
+
+    if( ctx->pk_info == NULL ||
         pk_hashlen_helper( md_alg, &hash_len ) != 0 )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
@@ -285,7 +297,11 @@
                    const unsigned char *hash, size_t hash_len,
                    const unsigned char *sig, size_t sig_len )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( hash != NULL );
+    PK_VALIDATE_RET( sig != NULL );
+
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ! mbedtls_pk_can_do( ctx, type ) )
@@ -345,7 +361,11 @@
              int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
              mbedtls_pk_restart_ctx *rs_ctx )
 {
-    if( ctx == NULL || ctx->pk_info == NULL ||
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( hash != NULL );
+    PK_VALIDATE_RET( sig != NULL );
+
+    if( ctx->pk_info == NULL ||
         pk_hashlen_helper( md_alg, &hash_len ) != 0 )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
@@ -399,7 +419,12 @@
                 unsigned char *output, size_t *olen, size_t osize,
                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( input != NULL || ilen == 0 );
+    PK_VALIDATE_RET( output != NULL || osize == 0 );
+    PK_VALIDATE_RET( olen != NULL );
+
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ctx->pk_info->decrypt_func == NULL )
@@ -417,7 +442,12 @@
                 unsigned char *output, size_t *olen, size_t osize,
                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( input != NULL || ilen == 0 );
+    PK_VALIDATE_RET( output != NULL || osize == 0 );
+    PK_VALIDATE_RET( olen != NULL );
+
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ctx->pk_info->encrypt_func == NULL )
@@ -432,8 +462,11 @@
  */
 int mbedtls_pk_check_pair( const mbedtls_pk_context *pub, const mbedtls_pk_context *prv )
 {
-    if( pub == NULL || pub->pk_info == NULL ||
-        prv == NULL || prv->pk_info == NULL ||
+    PK_VALIDATE_RET( pub != NULL );
+    PK_VALIDATE_RET( prv != NULL );
+
+    if( pub->pk_info == NULL ||
+        prv->pk_info == NULL ||
         prv->pk_info->check_pair_func == NULL )
     {
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
@@ -469,7 +502,8 @@
  */
 int mbedtls_pk_debug( const mbedtls_pk_context *ctx, mbedtls_pk_debug_item *items )
 {
-    if( ctx == NULL || ctx->pk_info == NULL )
+    PK_VALIDATE_RET( ctx != NULL );
+    if( ctx->pk_info == NULL )
         return( MBEDTLS_ERR_PK_BAD_INPUT_DATA );
 
     if( ctx->pk_info->debug_func == NULL )