1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// SHA1 block step.
// In its own file so that a faster assembly or C version
// can be substituted easily.
package sha1
import "sha1"
const (
_K0 = 0x5A827999;
_K1 = 0x6ED9EBA1;
_K2 = 0x8F1BBCDC;
_K3 = 0xCA62C1D6;
)
func _Block(dig *Digest, p []byte) int {
var w [80]uint32;
n := 0;
h0, h1, h2, h3, h4 := dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4];
for len(p) >= _Chunk {
// Can interlace the computation of w with the
// rounds below if needed for speed.
for i := 0; i < 16; i++ {
j := i*4;
w[i] = uint32(p[j])<<24 |
uint32(p[j+1])<<16 |
uint32(p[j+2])<<8 |
uint32(p[j+3]);
}
for i := 16; i < 80; i++ {
tmp := w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16];
w[i] = tmp<<1 | tmp>>(32-1);
}
a, b, c, d, e := h0, h1, h2, h3, h4;
// Each of the four 20-iteration rounds
// differs only in the computation of f and
// the choice of K (_K0, _K1, etc).
for i := 0; i < 20; i++ {
f := b&c | (^b)&d;
a5 := a<<5 | a>>(32-5);
b30 := b<<30 | b>>(32-30);
t := a5 + f + e + w[i] + _K0;
a, b, c, d, e = t, a, b30, c, d;
}
for i := 20; i < 40; i++ {
f := b ^ c ^ d;
a5 := a<<5 | a>>(32-5);
b30 := b<<30 | b>>(32-30);
t := a5 + f + e + w[i] + _K1;
a, b, c, d, e = t, a, b30, c, d;
}
for i := 40; i < 60; i++ {
f := b&c | b&d | c&d;
a5 := a<<5 | a>>(32-5);
b30 := b<<30 | b>>(32-30);
t := a5 + f + e + w[i] + _K2;
a, b, c, d, e = t, a, b30, c, d;
}
for i := 60; i < 80; i++ {
f := b ^ c ^ d;
a5 := a<<5 | a>>(32-5);
b30 := b<<30 | b>>(32-30);
t := a5 + f + e + w[i] + _K3;
a, b, c, d, e = t, a, b30, c, d;
}
h0 += a;
h1 += b;
h2 += c;
h3 += d;
h4 += e;
p = p[_Chunk:len(p)];
n += _Chunk;
}
dig.h[0], dig.h[1], dig.h[2], dig.h[3], dig.h[4] = h0, h1, h2, h3, h4;
return n;
}
|
