diff --git a/src/modules/frost/tests_impl.h b/src/modules/frost/tests_impl.h
index 16a7beb2..776f96b9 100644
--- a/src/modules/frost/tests_impl.h
+++ b/src/modules/frost/tests_impl.h
@@ -530,7 +530,7 @@ static void frost_nonce_test_internal(void) {
         msglen = testrand_int(sizeof(msg) + 1);
         testrand256(msg);
         extra_in_len = testrand_int(sizeof(extra_in) + 1);
-        testrand256(extra_in);
+        testrand_bytes_test(extra_in, sizeof(extra_in));
         if (testrand_bits(1)) {
             secp256k1_pubkey pubshare_tmp;
             CHECK(secp256k1_ec_pubkey_create(CTX, &pubshare_tmp, secshare) == 1);