base/md5.h

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