diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 0177add..2ff3249 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -7450,9 +7450,9 @@
             goto end;
         }
 
-        if( ( transform->psa_alg == MBEDTLS_SSL_NULL_CIPHER ||
-              transform->psa_alg == PSA_ALG_CBC_NO_PADDING ) &&
-            transform->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED )
+        if( ( transform->psa_alg == MBEDTLS_SSL_NULL_CIPHER ) ||
+            ( ( transform->psa_alg == PSA_ALG_CBC_NO_PADDING ) &&
+              ( transform->encrypt_then_mac == MBEDTLS_SSL_ETM_DISABLED ) ) )
             /* mbedtls_ct_hmac() requires the key to be exportable */
             psa_set_key_usage_flags( &attributes, PSA_KEY_USAGE_EXPORT |
                                                   PSA_KEY_USAGE_VERIFY_HASH );