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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
2 // for details. All rights reserved. Use of this source code is governed by a | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 | |
5 part of dart.crypto; | |
6 | |
7 // The SHA1 hasher is used to compute an SHA1 message digest. | |
8 class _SHA1 extends _HashBase implements SHA1 { | |
9 // Construct a SHA1 hasher object. | |
10 _SHA1() : _w = new List(80), super(16, 5, true) { | |
11 _h[0] = 0x67452301; | |
12 _h[1] = 0xEFCDAB89; | |
13 _h[2] = 0x98BADCFE; | |
14 _h[3] = 0x10325476; | |
15 _h[4] = 0xC3D2E1F0; | |
16 } | |
17 | |
18 // Returns a new instance of this Hash. | |
19 SHA1 newInstance() { | |
20 return new SHA1(); | |
21 } | |
22 | |
23 // Compute one iteration of the SHA1 algorithm with a chunk of | |
24 // 16 32-bit pieces. | |
25 void _updateHash(List<int> m) { | |
26 assert(m.length == 16); | |
27 | |
28 var a = _h[0]; | |
29 var b = _h[1]; | |
30 var c = _h[2]; | |
31 var d = _h[3]; | |
32 var e = _h[4]; | |
33 | |
34 for (var i = 0; i < 80; i++) { | |
35 if (i < 16) { | |
36 _w[i] = m[i]; | |
37 } else { | |
38 var n = _w[i - 3] ^ _w[i - 8] ^ _w[i - 14] ^ _w[i - 16]; | |
39 _w[i] = _rotl32(n, 1); | |
40 } | |
41 var t = _add32(_add32(_rotl32(a, 5), e), _w[i]); | |
42 if (i < 20) { | |
43 t = _add32(_add32(t, (b & c) | (~b & d)), 0x5A827999); | |
44 } else if (i < 40) { | |
45 t = _add32(_add32(t, (b ^ c ^ d)), 0x6ED9EBA1); | |
46 } else if (i < 60) { | |
47 t = _add32(_add32(t, (b & c) | (b & d) | (c & d)), 0x8F1BBCDC); | |
48 } else { | |
49 t = _add32(_add32(t, b ^ c ^ d), 0xCA62C1D6); | |
50 } | |
51 | |
52 e = d; | |
53 d = c; | |
54 c = _rotl32(b, 30); | |
55 b = a; | |
56 a = t & _MASK_32; | |
57 } | |
58 | |
59 _h[0] = _add32(a, _h[0]); | |
60 _h[1] = _add32(b, _h[1]); | |
61 _h[2] = _add32(c, _h[2]); | |
62 _h[3] = _add32(d, _h[3]); | |
63 _h[4] = _add32(e, _h[4]); | |
64 } | |
65 | |
66 List<int> _w; | |
67 } | |
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