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 8 #include <stddef.h> 9 #include <stdint.h> 10 11 #include "base/base_export.h" 12 #include "base/strings/string_piece.h" 13 14 namespace base { 15 16 // MD5 stands for Message Digest algorithm 5. 17 // MD5 is a robust hash function, designed for cyptography, but often used 18 // for file checksums. The code is complex and slow, but has few 19 // collisions. 20 // See Also: 21 // http://en.wikipedia.org/wiki/MD5 22 23 // These functions perform MD5 operations. The simplest call is MD5Sum() to 24 // generate the MD5 sum of the given data. 25 // 26 // You can also compute the MD5 sum of data incrementally by making multiple 27 // calls to MD5Update(): 28 // MD5Context ctx; // intermediate MD5 data: do not use 29 // MD5Init(&ctx); 30 // MD5Update(&ctx, data1, length1); 31 // MD5Update(&ctx, data2, length2); 32 // ... 33 // 34 // MD5Digest digest; // the result of the computation 35 // MD5Final(&digest, &ctx); 36 // 37 // You can call MD5DigestToBase16() to generate a string of the digest. 38 39 // The output of an MD5 operation. 40 struct MD5Digest { 41 uint8_t a[16]; 42 }; 43 44 // Used for storing intermediate data during an MD5 computation. Callers 45 // should not access the data. 46 typedef char MD5Context[88]; 47 48 // Initializes the given MD5 context structure for subsequent calls to 49 // MD5Update(). 50 BASE_EXPORT void MD5Init(MD5Context* context); 51 52 // For the given buffer of |data| as a StringPiece, updates the given MD5 53 // context with the sum of the data. You can call this any number of times 54 // during the computation, except that MD5Init() must have been called first. 55 BASE_EXPORT void MD5Update(MD5Context* context, const StringPiece& data); 56 57 // Finalizes the MD5 operation and fills the buffer with the digest. 58 BASE_EXPORT void MD5Final(MD5Digest* digest, MD5Context* context); 59 60 // MD5IntermediateFinal() generates a digest without finalizing the MD5 61 // operation. Can be used to generate digests for the input seen thus far, 62 // without affecting the digest generated for the entire input. 63 BASE_EXPORT void MD5IntermediateFinal(MD5Digest* digest, 64 const MD5Context* context); 65 66 // Converts a digest into human-readable hexadecimal. 67 BASE_EXPORT std::string MD5DigestToBase16(const MD5Digest& digest); 68 69 // Computes the MD5 sum of the given data buffer with the given length. 70 // The given 'digest' structure will be filled with the result data. 71 BASE_EXPORT void MD5Sum(const void* data, size_t length, MD5Digest* digest); 72 73 // Returns the MD5 (in hexadecimal) of a string. 74 BASE_EXPORT std::string MD5String(const StringPiece& str); 75 76 } // namespace base 77 78 #endif // BASE_MD5_H_ 79
