md5.h revision 3345a6884c488ff3a535c2c9acdd33d74b37e311 
1// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_MD5_H_
6#define BASE_MD5_H_
7#pragma once
8
9#include <string>
10
11// MD5 stands for Message Digest algorithm 5.
12// MD5 is a robust hash function, designed for cyptography, but often used
13// for file checksums.  The code is complex and slow, but has few
14// collisions.
15// See Also:
16//   http://en.wikipedia.org/wiki/MD5
17
18// These functions perform MD5 operations. The simplest call is MD5Sum() to
19// generate the MD5 sum of the given data.
20//
21// You can also compute the MD5 sum of data incrementally by making multiple
22// calls to MD5Update():
23//   MD5Context ctx; // intermediate MD5 data: do not use
24//   MD5Init(&ctx);
25//   MD5Update(&ctx, data1, length1);
26//   MD5Update(&ctx, data2, length2);
27//   ...
28//
29//   MD5Digest digest; // the result of the computation
30//   MD5Final(&digest, &ctx);
31//
32// You can call MD5DigestToBase16() to generate a string of the digest.
33
34// The output of an MD5 operation
35typedef struct MD5Digest_struct {
36  unsigned char a[16];
37} MD5Digest;
38
39// Used for storing intermediate data during an MD5 computation. Callers
40// should not access the data.
41typedef char MD5Context[88];
42
43// Computes the MD5 sum of the given data buffer with the given length.
44// The given 'digest' structure will be filled with the result data.
45void MD5Sum(const void* data, size_t length, MD5Digest* digest);
46
47// Initializes the given MD5 context structure for subsequent calls to
48// MD5Update().
49void MD5Init(MD5Context* context);
50
51// For the given buffer of data, updates the given MD5 context with the sum of
52// the data. You can call this any number of times during the computation,
53// except that MD5Init() must have been called first.
54void MD5Update(MD5Context* context, const void* buf, size_t len);
55
56// Finalizes the MD5 operation and fills the buffer with the digest.
57void MD5Final(MD5Digest* digest, MD5Context* pCtx);
58
59// Converts a digest into human-readable hexadecimal.
60std::string MD5DigestToBase16(const MD5Digest& digest);
61
62// Returns the MD5 (in hexadecimal) of a string.
63std::string MD5String(const std::string& str);
64
65#endif  // BASE_MD5_H_
66
67