1/*
2 * libjingle
3 * Copyright 2004, Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef TALK_BASE_MESSAGEDIGEST_H_
29#define TALK_BASE_MESSAGEDIGEST_H_
30
31#include <string>
32
33namespace talk_base {
34
35// Definitions for the digest algorithms.
36extern const char DIGEST_MD5[];
37extern const char DIGEST_SHA_1[];
38extern const char DIGEST_SHA_224[];
39extern const char DIGEST_SHA_256[];
40extern const char DIGEST_SHA_384[];
41extern const char DIGEST_SHA_512[];
42
43// A general class for computing hashes.
44class MessageDigest {
45 public:
46  enum { kMaxSize = 64 };  // Maximum known size (SHA-512)
47  virtual ~MessageDigest() {}
48  // Returns the digest output size (e.g. 16 bytes for MD5).
49  virtual size_t Size() const = 0;
50  // Updates the digest with |len| bytes from |buf|.
51  virtual void Update(const void* buf, size_t len) = 0;
52  // Outputs the digest value to |buf| with length |len|.
53  // Returns the number of bytes written, i.e., Size().
54  virtual size_t Finish(void* buf, size_t len) = 0;
55};
56
57// A factory class for creating digest objects.
58class MessageDigestFactory {
59 public:
60  static MessageDigest* Create(const std::string& alg);
61};
62
63// Functions to create hashes.
64
65// Computes the hash of |in_len| bytes of |input|, using the |digest| hash
66// implementation, and outputs the hash to the buffer |output|, which is
67// |out_len| bytes long. Returns the number of bytes written to |output| if
68// successful, or 0 if |out_len| was too small.
69size_t ComputeDigest(MessageDigest* digest, const void* input, size_t in_len,
70                     void* output, size_t out_len);
71// Like the previous function, but creates a digest implementation based on
72// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns 0 if there is no
73// digest with the given name.
74size_t ComputeDigest(const std::string& alg, const void* input, size_t in_len,
75                     void* output, size_t out_len);
76// Computes the hash of |input| using the |digest| hash implementation, and
77// returns it as a hex-encoded string.
78std::string ComputeDigest(MessageDigest* digest, const std::string& input);
79// Like the previous function, but creates a digest implementation based on
80// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns empty string if
81// there is no digest with the given name.
82std::string ComputeDigest(const std::string& alg, const std::string& input);
83// Like the previous function, but returns an explicit result code.
84bool ComputeDigest(const std::string& alg, const std::string& input,
85                   std::string* output);
86
87// Shorthand way to compute a hex-encoded hash using MD5.
88inline std::string MD5(const std::string& input) {
89  return ComputeDigest(DIGEST_MD5, input);
90}
91
92// Functions to compute RFC 2104 HMACs.
93
94// Computes the HMAC of |in_len| bytes of |input|, using the |digest| hash
95// implementation and |key_len| bytes of |key| to key the HMAC, and outputs
96// the HMAC to the buffer |output|, which is |out_len| bytes long. Returns the
97// number of bytes written to |output| if successful, or 0 if |out_len| was too
98// small.
99size_t ComputeHmac(MessageDigest* digest, const void* key, size_t key_len,
100                   const void* input, size_t in_len,
101                   void* output, size_t out_len);
102// Like the previous function, but creates a digest implementation based on
103// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns 0 if there is no
104// digest with the given name.
105size_t ComputeHmac(const std::string& alg, const void* key, size_t key_len,
106                   const void* input, size_t in_len,
107                   void* output, size_t out_len);
108// Computes the HMAC of |input| using the |digest| hash implementation and |key|
109// to key the HMAC, and returns it as a hex-encoded string.
110std::string ComputeHmac(MessageDigest* digest, const std::string& key,
111                        const std::string& input);
112// Like the previous function, but creates a digest implementation based on
113// the desired digest name |alg|, e.g. DIGEST_SHA_1. Returns empty string if
114// there is no digest with the given name.
115std::string ComputeHmac(const std::string& alg, const std::string& key,
116                        const std::string& input);
117// Like the previous function, but returns an explicit result code.
118bool ComputeHmac(const std::string& alg, const std::string& key,
119                 const std::string& input, std::string* output);
120
121}  // namespace talk_base
122
123#endif  // TALK_BASE_MESSAGEDIGEST_H_
124