From 6fce81637e3c0e0300d9eb9519161764f58be7b5 Mon Sep 17 00:00:00 2001
From: Ron Eldor <Ron.Eldor@arm.com>
Date: Mon, 28 Jan 2019 15:01:53 +0200
Subject: [PATCH] Add explanation for okm_string size

Add explanation for why the size of `okm_string` buffer
is twice as `okm` buffer.
---
 tests/suites/test_suite_hkdf.function | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tests/suites/test_suite_hkdf.function b/tests/suites/test_suite_hkdf.function
index e41422a63..fc0e24217 100644
--- a/tests/suites/test_suite_hkdf.function
+++ b/tests/suites/test_suite_hkdf.function
@@ -19,6 +19,10 @@ void test_hkdf( int md_alg, char *hex_ikm_string, char *hex_salt_string,
     unsigned char info[128] = { '\0' };
     unsigned char expected_okm[128] = { '\0' };
     unsigned char okm[128] = { '\0' };
+    /*
+     * okm_string is the string representation of okm,
+     * so its size is twice as the size of okm.
+     */
     unsigned char okm_string[256] = { '\0' };
 
     const mbedtls_md_info_t *md = mbedtls_md_info_from_type( md_alg );