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
|
/*
* SSLv3 PRF
* (C) 2004-2006 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/prf_ssl3.h>
#include <botan/symkey.h>
#include <botan/exceptn.h>
#include <botan/sha160.h>
#include <botan/md5.h>
#include <botan/internal/assert.h>
#include <memory>
namespace Botan {
namespace {
/*
* Return the next inner hash
*/
OctetString next_hash(size_t where, size_t want,
HashFunction& md5, HashFunction& sha1,
const byte secret[], size_t secret_len,
const byte seed[], size_t seed_len)
{
BOTAN_ASSERT(want <= md5.OUTPUT_LENGTH, "Desired output too large");
const byte ASCII_A_CHAR = 0x41;
for(size_t j = 0; j != where + 1; j++)
sha1.update(ASCII_A_CHAR + where);
sha1.update(secret, secret_len);
sha1.update(seed, seed_len);
SecureVector<byte> sha1_hash = sha1.final();
md5.update(secret, secret_len);
md5.update(sha1_hash);
SecureVector<byte> md5_hash = md5.final();
return OctetString(&md5_hash[0], want);
}
}
/*
* SSL3 PRF
*/
SecureVector<byte> SSL3_PRF::derive(size_t key_len,
const byte secret[], size_t secret_len,
const byte seed[], size_t seed_len) const
{
if(key_len > 416)
throw Invalid_Argument("SSL3_PRF: Requested key length is too large");
MD5 md5;
SHA_160 sha1;
OctetString output;
int counter = 0;
while(key_len)
{
const size_t produce = std::min<size_t>(key_len, md5.OUTPUT_LENGTH);
output = output + next_hash(counter++, produce, md5, sha1,
secret, secret_len, seed, seed_len);
key_len -= produce;
}
return output.bits_of();
}
}
|
