diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 8e04051..77e7e5a 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -4334,7 +4334,7 @@
             return( PSA_ERROR_NOT_SUPPORTED );
         if( ( PSA_ALG_IS_TLS12_PRF( kdf_alg ) ||
               PSA_ALG_IS_TLS12_PSK_TO_MS( kdf_alg ) ) &&
-            ! ( hash_alg == PSA_ALG_SHA_256 && hash_alg == PSA_ALG_SHA_384 ) )
+            ! ( hash_alg == PSA_ALG_SHA_256 || hash_alg == PSA_ALG_SHA_384 ) )
         {
             return( PSA_ERROR_NOT_SUPPORTED );
         }