summaryrefslogtreecommitdiffstats
blob: e695e13b21379b5694ad3856132088db961042a4 (plain)
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
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
// boost/uuid/sha1.hpp header file  ----------------------------------------------//

// Copyright 2007 Andy Tompkins.
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

// Revision History
//  29 May 2007 - Initial Revision
//  25 Feb 2008 - moved to namespace boost::uuids::detail
//  10 Jan 2012 - can now handle the full size of messages (2^64 - 1 bits)

// This is a byte oriented implementation

#ifndef BOOST_UUID_SHA1_H
#define BOOST_UUID_SHA1_H

#include <boost/static_assert.hpp>
#include <stdexcept>
#include <boost/throw_exception.hpp>
#include <cstddef>
#include <string>

#ifdef BOOST_NO_STDC_NAMESPACE
namespace std {
    using ::size_t;
} // namespace std
#endif

namespace boost {
namespace uuids {
namespace detail {

BOOST_STATIC_ASSERT(sizeof(unsigned char)*8 == 8);
BOOST_STATIC_ASSERT(sizeof(unsigned int)*8 == 32);

inline unsigned int left_rotate(unsigned int x, std::size_t n)
{
    return (x<<n) ^ (x>> (32-n));
}

class sha1
{
public:
    typedef unsigned int(&digest_type)[5];
public:
    sha1();

    void reset();

    void process_byte(unsigned char byte);
    void process_block(void const* bytes_begin, void const* bytes_end);
    void process_bytes(void const* buffer, std::size_t byte_count);

    void get_digest(digest_type digest);

private:
    void process_block();
    void process_byte_impl(unsigned char byte);

private:
    unsigned int h_[5];

    unsigned char block_[64];

    std::size_t block_byte_index_;
    std::size_t bit_count_low;
    std::size_t bit_count_high;
};

inline sha1::sha1()
{
    reset();
}

inline void sha1::reset()
{
    h_[0] = 0x67452301;
    h_[1] = 0xEFCDAB89;
    h_[2] = 0x98BADCFE;
    h_[3] = 0x10325476;
    h_[4] = 0xC3D2E1F0;

    block_byte_index_ = 0;
    bit_count_low = 0;
    bit_count_high = 0;
}

inline void sha1::process_byte(unsigned char byte)
{
    process_byte_impl(byte);

    // size_t max value = 0xFFFFFFFF
    //if (bit_count_low + 8 >= 0x100000000) { // would overflow
    //if (bit_count_low >= 0x100000000-8) {
    if (bit_count_low < 0xFFFFFFF8) {
        bit_count_low += 8;
    } else {
        bit_count_low = 0;

        if (bit_count_high <= 0xFFFFFFFE) {
            ++bit_count_high;
        } else {
            BOOST_THROW_EXCEPTION(std::runtime_error("sha1 too many bytes"));
        }
    }
}

inline void sha1::process_byte_impl(unsigned char byte)
{
    block_[block_byte_index_++] = byte;

    if (block_byte_index_ == 64) {
        block_byte_index_ = 0;
        process_block();
    }
}

inline void sha1::process_block(void const* bytes_begin, void const* bytes_end)
{
    unsigned char const* begin = static_cast<unsigned char const*>(bytes_begin);
    unsigned char const* end = static_cast<unsigned char const*>(bytes_end);
    for(; begin != end; ++begin) {
        process_byte(*begin);
    }
}

inline void sha1::process_bytes(void const* buffer, std::size_t byte_count)
{
    unsigned char const* b = static_cast<unsigned char const*>(buffer);
    process_block(b, b+byte_count);
}

inline void sha1::process_block()
{
    unsigned int w[80];
    for (std::size_t i=0; i<16; ++i) {
        w[i]  = (block_[i*4 + 0] << 24);
        w[i] |= (block_[i*4 + 1] << 16);
        w[i] |= (block_[i*4 + 2] << 8);
        w[i] |= (block_[i*4 + 3]);
    }
    for (std::size_t i=16; i<80; ++i) {
        w[i] = left_rotate((w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16]), 1);
    }

    unsigned int a = h_[0];
    unsigned int b = h_[1];
    unsigned int c = h_[2];
    unsigned int d = h_[3];
    unsigned int e = h_[4];

    for (std::size_t i=0; i<80; ++i) {
        unsigned int f;
        unsigned int k;

        if (i<20) {
            f = (b & c) | (~b & d);
            k = 0x5A827999;
        } else if (i<40) {
            f = b ^ c ^ d;
            k = 0x6ED9EBA1;
        } else if (i<60) {
            f = (b & c) | (b & d) | (c & d);
            k = 0x8F1BBCDC;
        } else {
            f = b ^ c ^ d;
            k = 0xCA62C1D6;
        }

        unsigned temp = left_rotate(a, 5) + f + e + k + w[i];
        e = d;
        d = c;
        c = left_rotate(b, 30);
        b = a;
        a = temp;
    }

    h_[0] += a;
    h_[1] += b;
    h_[2] += c;
    h_[3] += d;
    h_[4] += e;
}

inline void sha1::get_digest(digest_type digest)
{
    // append the bit '1' to the message
    process_byte_impl(0x80);

    // append k bits '0', where k is the minimum number >= 0
    // such that the resulting message length is congruent to 56 (mod 64)
    // check if there is enough space for padding and bit_count
    if (block_byte_index_ > 56) {
        // finish this block
        while (block_byte_index_ != 0) {
            process_byte_impl(0);
        }

        // one more block
        while (block_byte_index_ < 56) {
            process_byte_impl(0);
        }
    } else {
        while (block_byte_index_ < 56) {
            process_byte_impl(0);
        }
    }

    // append length of message (before pre-processing) 
    // as a 64-bit big-endian integer
    process_byte_impl( static_cast<unsigned char>((bit_count_high>>24) & 0xFF) );
    process_byte_impl( static_cast<unsigned char>((bit_count_high>>16) & 0xFF) );
    process_byte_impl( static_cast<unsigned char>((bit_count_high>>8 ) & 0xFF) );
    process_byte_impl( static_cast<unsigned char>((bit_count_high)     & 0xFF) );
    process_byte_impl( static_cast<unsigned char>((bit_count_low>>24) & 0xFF) );
    process_byte_impl( static_cast<unsigned char>((bit_count_low>>16) & 0xFF) );
    process_byte_impl( static_cast<unsigned char>((bit_count_low>>8 ) & 0xFF) );
    process_byte_impl( static_cast<unsigned char>((bit_count_low)     & 0xFF) );

    // get final digest
    digest[0] = h_[0];
    digest[1] = h_[1];
    digest[2] = h_[2];
    digest[3] = h_[3];
    digest[4] = h_[4];
}

}}} // namespace boost::uuids::detail

#endif