HMAC-SHA1 implementation for Mac based on CommonCrypto;

allow Windows HMAC-SHA1 to use keys longer than 16 bytes.
Review URL: http://codereview.chromium.org/218

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@1724 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 52 insertions, 0 deletions

diff --git a/base/hmac_mac.cc b/base/hmac_mac.cc
new file mode 100644
index 0000000..0542a70
--- /dev/null
+++ b/base/hmac_mac.cc
@@ -0,0 +1,52 @@
+// Copyright (c) 2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/hmac.h"
+
+#include <CommonCrypto/CommonHMAC.h>
+
+#include "base/logging.h"
+
+namespace base {
+
+HMAC::HMAC(HashAlgorithm hash_alg, const unsigned char* key, int key_length)
+    : hash_alg_(hash_alg),
+      key_(reinterpret_cast<const char*>(key), key_length) {
+}
+
+HMAC::~HMAC() {
+  // Zero out key copy.
+  key_.assign(key_.length(), std::string::value_type());
+  key_.clear();
+  key_.reserve(0);
+}
+
+bool HMAC::Sign(const std::string& data,
+                unsigned char* digest,
+                int digest_length) {
+  CCHmacAlgorithm algorithm;
+  int algorithm_digest_length;
+  switch (hash_alg_) {
+    case SHA1:
+      algorithm = kCCHmacAlgSHA1;
+      algorithm_digest_length = CC_SHA1_DIGEST_LENGTH;
+      break;
+    default:
+      NOTREACHED();
+      return false;
+  }
+
+  if (digest_length < algorithm_digest_length) {
+    NOTREACHED();
+    return false;
+  }
+
+  CCHmac(algorithm,
+         key_.data(), key_.length(), data.data(), data.length(),
+         digest);
+
+  return true;
+}
+
+}  // namespace base