diff --git a/library/sha256.c b/library/sha256.c
index ac15ef8d1d..24be8eac2b 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -159,8 +159,6 @@ static int mbedtls_a64_crypto_sha256_determine_support( void )
 
 void mbedtls_sha256_init( mbedtls_sha256_context *ctx )
 {
-    SHA256_VALIDATE( ctx != NULL );
-
     memset( ctx, 0, sizeof( mbedtls_sha256_context ) );
 }
 
@@ -175,9 +173,6 @@ void mbedtls_sha256_free( mbedtls_sha256_context *ctx )
 void mbedtls_sha256_clone( mbedtls_sha256_context *dst,
                            const mbedtls_sha256_context *src )
 {
-    SHA256_VALIDATE( dst != NULL );
-    SHA256_VALIDATE( src != NULL );
-
     *dst = *src;
 }
 
@@ -186,8 +181,6 @@ void mbedtls_sha256_clone( mbedtls_sha256_context *dst,
  */
 int mbedtls_sha256_starts( mbedtls_sha256_context *ctx, int is224 )
 {
-    SHA256_VALIDATE_RET( ctx != NULL );
-
 #if defined(MBEDTLS_SHA224_C)
     SHA256_VALIDATE_RET( is224 == 0 || is224 == 1 );
 #else
@@ -427,9 +420,6 @@ int mbedtls_internal_sha256_process_c( mbedtls_sha256_context *ctx,
 
     unsigned int i;
 
-    SHA256_VALIDATE_RET( ctx != NULL );
-    SHA256_VALIDATE_RET( (const unsigned char *)data != NULL );
-
     for( i = 0; i < 8; i++ )
         local.A[i] = ctx->state[i];
 
@@ -579,9 +569,6 @@ int mbedtls_sha256_update( mbedtls_sha256_context *ctx,
     size_t fill;
     uint32_t left;
 
-    SHA256_VALIDATE_RET( ctx != NULL );
-    SHA256_VALIDATE_RET( ilen == 0 || input != NULL );
-
     if( ilen == 0 )
         return( 0 );
 
@@ -633,9 +620,6 @@ int mbedtls_sha256_finish( mbedtls_sha256_context *ctx,
     uint32_t used;
     uint32_t high, low;
 
-    SHA256_VALIDATE_RET( ctx != NULL );
-    SHA256_VALIDATE_RET( (unsigned char *)output != NULL );
-
     /*
      * Add padding: 0x80 then 0x00 until 8 bytes remain for the length
      */
@@ -710,9 +694,6 @@ int mbedtls_sha256( const unsigned char *input,
     SHA256_VALIDATE_RET( is224 == 0 );
 #endif
 
-    SHA256_VALIDATE_RET( ilen == 0 || input != NULL );
-    SHA256_VALIDATE_RET( (unsigned char *)output != NULL );
-
     mbedtls_sha256_init( &ctx );
 
     if( ( ret = mbedtls_sha256_starts( &ctx, is224 ) ) != 0 )