diff --git a/library/des.c b/library/des.c
index c920328..8f01ec1 100644
--- a/library/des.c
+++ b/library/des.c
@@ -417,7 +417,7 @@
     int i;
 
     for( i = 0; i < WEAK_KEY_COUNT; i++ )
-        if( mbedtls_platform_memcmp( weak_key_table[i], key, MBEDTLS_DES_KEY_SIZE) == 0 )
+        if( mbedtls_platform_memequal( weak_key_table[i], key, MBEDTLS_DES_KEY_SIZE) == 0 )
             return( 1 );
 
     return( 0 );