diff --git a/library/nist_kw.c b/library/nist_kw.c
index 0ad270a..5b5aa1c 100644
--- a/library/nist_kw.c
+++ b/library/nist_kw.c
@@ -222,7 +222,10 @@
         }
 
         mbedtls_platform_memcpy( output, NIST_KW_ICV1, KW_SEMIBLOCK_LENGTH );
-        memmove( output + KW_SEMIBLOCK_LENGTH, input, in_len );
+        if( 0 != mbedtls_platform_memmove( output + KW_SEMIBLOCK_LENGTH, input, in_len ) )
+        {
+            return MBEDTLS_ERR_CIPHER_ALLOC_FAILED;
+        }
     }
     else
     {
@@ -343,7 +346,11 @@
     }
 
     mbedtls_platform_memcpy( A, input, KW_SEMIBLOCK_LENGTH );
-    memmove( output, input + KW_SEMIBLOCK_LENGTH, ( semiblocks - 1 ) * KW_SEMIBLOCK_LENGTH );
+    if( 0 != mbedtls_platform_memmove( output, input + KW_SEMIBLOCK_LENGTH,
+                                       ( semiblocks - 1 ) * KW_SEMIBLOCK_LENGTH ) )
+    {
+        return( MBEDTLS_ERR_CIPHER_ALLOC_FAILED );
+    }
 
     /* Calculate intermediate values */
     for( t = s; t >= 1; t-- )