Home | History | Annotate | Download | only in base
      1 // Copyright (c) 2011 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 #include "base/base_api.h"
     12 
     13 // MD5 stands for Message Digest algorithm 5.
     14 // MD5 is a robust hash function, designed for cyptography, but often used
     15 // for file checksums.  The code is complex and slow, but has few
     16 // collisions.
     17 // See Also:
     18 //   http://en.wikipedia.org/wiki/MD5
     19 
     20 // These functions perform MD5 operations. The simplest call is MD5Sum() to
     21 // generate the MD5 sum of the given data.
     22 //
     23 // You can also compute the MD5 sum of data incrementally by making multiple
     24 // calls to MD5Update():
     25 //   MD5Context ctx; // intermediate MD5 data: do not use
     26 //   MD5Init(&ctx);
     27 //   MD5Update(&ctx, data1, length1);
     28 //   MD5Update(&ctx, data2, length2);
     29 //   ...
     30 //
     31 //   MD5Digest digest; // the result of the computation
     32 //   MD5Final(&digest, &ctx);
     33 //
     34 // You can call MD5DigestToBase16() to generate a string of the digest.
     35 
     36 // The output of an MD5 operation
     37 typedef struct MD5Digest_struct {
     38   unsigned char a[16];
     39 } MD5Digest;
     40 
     41 // Used for storing intermediate data during an MD5 computation. Callers
     42 // should not access the data.
     43 typedef char MD5Context[88];
     44 
     45 // Computes the MD5 sum of the given data buffer with the given length.
     46 // The given 'digest' structure will be filled with the result data.
     47 BASE_API void MD5Sum(const void* data, size_t length, MD5Digest* digest);
     48 
     49 // Initializes the given MD5 context structure for subsequent calls to
     50 // MD5Update().
     51 BASE_API void MD5Init(MD5Context* context);
     52 
     53 // For the given buffer of data, updates the given MD5 context with the sum of
     54 // the data. You can call this any number of times during the computation,
     55 // except that MD5Init() must have been called first.
     56 BASE_API void MD5Update(MD5Context* context, const void* buf, size_t len);
     57 
     58 // Finalizes the MD5 operation and fills the buffer with the digest.
     59 BASE_API void MD5Final(MD5Digest* digest, MD5Context* pCtx);
     60 
     61 // Converts a digest into human-readable hexadecimal.
     62 BASE_API std::string MD5DigestToBase16(const MD5Digest& digest);
     63 
     64 // Returns the MD5 (in hexadecimal) of a string.
     65 BASE_API std::string MD5String(const std::string& str);
     66 
     67 #endif  // BASE_MD5_H_
     68 
     69