diff options
Diffstat (limited to 'base/hmac.h')
| -rw-r--r-- | base/hmac.h | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/base/hmac.h b/base/hmac.h new file mode 100644 index 0000000..37c8fc9 --- /dev/null +++ b/base/hmac.h @@ -0,0 +1,87 @@ +// Copyright 2008, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// +// Utility class for calculating the HMAC for a given message. We currently +// only support SHA1 for the hash algorithm, but this can be extended easily. + +#ifndef BASE_HMAC_H__ +#define BASE_HMAC_H__ + +#include <windows.h> +#include <wincrypt.h> + +#include <string> + +#include "base/basictypes.h" + +class HMAC { + public: + // The set of supported hash functions. Extend as required. + enum HashAlgorithm { + SHA1 + }; + + HMAC(HashAlgorithm hash_alg, const unsigned char* key, int key_length); + ~HMAC(); + + // Returns the HMAC in 'digest' for the message in 'data' and the key + // specified in the contructor. + bool Sign(const std::string& data, unsigned char* digest, int digest_length); + + private: + // Import the key so that we don't have to store it ourself. + // TODO(paulg): Bug: http://b/1084719, 'ImportKey' will not currently work on + // Windows 2000 since it requires special handling for importing + // keys. See this link for details: + // http://www.derkeiler.com/Newsgroups/microsoft.public.platformsdk.security/2004-06/0270.html + void ImportKey(const unsigned char* key, int key_length); + + // Returns the SHA1 hash of 'data' and 'key' in 'digest'. If there was any + // error in the calculation, this method returns false, otherwise true. + bool SignWithSHA1(const std::string& data, + unsigned char* digest, + int digest_length); + + // Required for the SHA1 key_blob struct. We limit this to 16 bytes since + // Windows 2000 doesn't support keys larger than that. + static const int kMaxKeySize = 16; + + // The hash algorithm to use. + HashAlgorithm hash_alg_; + + // Windows Crypt API resources. + HCRYPTPROV provider_; + HCRYPTHASH hash_; + HCRYPTKEY hkey_; + + DISALLOW_EVIL_CONSTRUCTORS(HMAC); +}; + + +#endif // BASE_HMAC_H__
\ No newline at end of file |