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* Copyright 2004, Google Inc.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
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* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef TALK_BASE_MESSAGEDIGEST_H_
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#define TALK_BASE_MESSAGEDIGEST_H_
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// Definitions for the digest algorithms.
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extern const char DIGEST_MD5[];
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extern const char DIGEST_SHA_1[];
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extern const char DIGEST_SHA_224[];
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extern const char DIGEST_SHA_256[];
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extern const char DIGEST_SHA_384[];
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extern const char DIGEST_SHA_512[];
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// A general class for computing hashes.
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virtual ~MessageDigest() {}
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// Returns the digest output size (e.g. 16 bytes for MD5).
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virtual size_t Size() const = 0;
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// Updates the digest with |len| bytes from |buf|.
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virtual void Update(const void* buf, size_t len) = 0;
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// Outputs the digest value to |buf| with length |len|.
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// Returns the number of bytes written, i.e., Size().
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virtual size_t Finish(void* buf, size_t len) = 0;
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// A factory class for creating digest objects.
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class MessageDigestFactory {
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static MessageDigest* Create(const std::string& alg);
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// Functions to create hashes.
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// Computes the hash of |in_len| bytes of |input|, using the |digest| hash
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// implementation, and outputs the hash to the buffer |output|, which is
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// |out_len| bytes long. Returns the number of bytes written to |output| if
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// successful, or 0 if |out_len| was too small.
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size_t ComputeDigest(MessageDigest* digest, const void* input, size_t in_len,
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void* output, size_t out_len);
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// Like the previous function, but creates a digest implementation based on
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// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns 0 if there is no
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// digest with the given name.
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size_t ComputeDigest(const std::string& alg, const void* input, size_t in_len,
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void* output, size_t out_len);
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// Computes the hash of |input| using the |digest| hash implementation, and
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// returns it as a hex-encoded string.
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std::string ComputeDigest(MessageDigest* digest, const std::string& input);
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// Like the previous function, but creates a digest implementation based on
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// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns empty string if
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// there is no digest with the given name.
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std::string ComputeDigest(const std::string& alg, const std::string& input);
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// Like the previous function, but returns an explicit result code.
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bool ComputeDigest(const std::string& alg, const std::string& input,
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// Shorthand way to compute a hex-encoded hash using MD5.
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inline std::string MD5(const std::string& input) {
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return ComputeDigest(DIGEST_MD5, input);
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// Functions to compute RFC 2104 HMACs.
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// Computes the HMAC of |in_len| bytes of |input|, using the |digest| hash
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// implementation and |key_len| bytes of |key| to key the HMAC, and outputs
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// the HMAC to the buffer |output|, which is |out_len| bytes long. Returns the
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// number of bytes written to |output| if successful, or 0 if |out_len| was too
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size_t ComputeHmac(MessageDigest* digest, const void* key, size_t key_len,
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const void* input, size_t in_len,
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void* output, size_t out_len);
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// Like the previous function, but creates a digest implementation based on
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// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns 0 if there is no
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// digest with the given name.
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size_t ComputeHmac(const std::string& alg, const void* key, size_t key_len,
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const void* input, size_t in_len,
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void* output, size_t out_len);
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// Computes the HMAC of |input| using the |digest| hash implementation and |key|
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// to key the HMAC, and returns it as a hex-encoded string.
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std::string ComputeHmac(MessageDigest* digest, const std::string& key,
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const std::string& input);
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// Like the previous function, but creates a digest implementation based on
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// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns empty string if
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// there is no digest with the given name.
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std::string ComputeHmac(const std::string& alg, const std::string& key,
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const std::string& input);
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// Like the previous function, but returns an explicit result code.
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bool ComputeHmac(const std::string& alg, const std::string& key,
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const std::string& input, std::string* output);
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} // namespace talk_base
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#endif // TALK_BASE_MESSAGEDIGEST_H_