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
|
/*
* Passhash9 Password Hashing
* (C) 2010 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/passhash9.h>
#include <botan/loadstor.h>
#include <botan/pbkdf2.h>
#include <botan/base64.h>
namespace Botan {
namespace {
const std::string MAGIC_PREFIX = "$9$";
const size_t WORKFACTOR_BYTES = 2;
const size_t ALGID_BYTES = 1;
const size_t SALT_BYTES = 12; // 96 bits of salt
const size_t PASSHASH9_PBKDF_OUTPUT_LEN = 24; // 192 bits output
const size_t WORK_FACTOR_SCALE = 10000;
std::unique_ptr<MessageAuthenticationCode> get_pbkdf_prf(uint8_t alg_id)
{
if(alg_id == 0)
return MessageAuthenticationCode::create("HMAC(SHA-1)");
else if(alg_id == 1)
return MessageAuthenticationCode::create("HMAC(SHA-256)");
else if(alg_id == 2)
return MessageAuthenticationCode::create("CMAC(Blowfish)");
else if(alg_id == 3)
return MessageAuthenticationCode::create("HMAC(SHA-384)");
else if(alg_id == 4)
return MessageAuthenticationCode::create("HMAC(SHA-512)");
return nullptr;
}
}
std::string generate_passhash9(const std::string& pass,
RandomNumberGenerator& rng,
uint16_t work_factor,
uint8_t alg_id)
{
std::unique_ptr<MessageAuthenticationCode> prf = get_pbkdf_prf(alg_id);
if(!prf)
throw Invalid_Argument("Passhash9: Algorithm id " +
std::to_string(alg_id) +
" is not defined");
PKCS5_PBKDF2 kdf(prf.release()); // takes ownership of pointer
secure_vector<uint8_t> salt(SALT_BYTES);
rng.randomize(salt.data(), salt.size());
const size_t kdf_iterations = WORK_FACTOR_SCALE * work_factor;
secure_vector<uint8_t> blob;
blob.push_back(alg_id);
blob.push_back(get_byte(0, work_factor));
blob.push_back(get_byte(1, work_factor));
blob += salt;
blob += kdf.derive_key(PASSHASH9_PBKDF_OUTPUT_LEN,
pass,
salt.data(), salt.size(),
kdf_iterations).bits_of();
return MAGIC_PREFIX + base64_encode(blob);
}
bool check_passhash9(const std::string& pass, const std::string& hash)
{
const size_t BINARY_LENGTH =
ALGID_BYTES +
WORKFACTOR_BYTES +
PASSHASH9_PBKDF_OUTPUT_LEN +
SALT_BYTES;
const size_t BASE64_LENGTH =
MAGIC_PREFIX.size() + (BINARY_LENGTH * 8) / 6;
if(hash.size() != BASE64_LENGTH)
return false;
for(size_t i = 0; i != MAGIC_PREFIX.size(); ++i)
if(hash[i] != MAGIC_PREFIX[i])
return false;
secure_vector<uint8_t> bin = base64_decode(hash.c_str() + MAGIC_PREFIX.size());
if(bin.size() != BINARY_LENGTH)
return false;
uint8_t alg_id = bin[0];
const size_t work_factor = load_be<uint16_t>(&bin[ALGID_BYTES], 0);
// Bug in the format, bad states shouldn't be representable, but are...
if(work_factor == 0)
return false;
if(work_factor > 512)
throw Invalid_Argument("Requested Bcrypt work factor " +
std::to_string(work_factor) + " too large");
const size_t kdf_iterations = WORK_FACTOR_SCALE * work_factor;
std::unique_ptr<MessageAuthenticationCode> pbkdf_prf = get_pbkdf_prf(alg_id);
if(!pbkdf_prf)
return false; // unknown algorithm, reject
PKCS5_PBKDF2 kdf(pbkdf_prf.release()); // takes ownership of pointer
secure_vector<uint8_t> cmp = kdf.derive_key(
PASSHASH9_PBKDF_OUTPUT_LEN,
pass,
&bin[ALGID_BYTES + WORKFACTOR_BYTES], SALT_BYTES,
kdf_iterations).bits_of();
return same_mem(cmp.data(),
&bin[ALGID_BYTES + WORKFACTOR_BYTES + SALT_BYTES],
PASSHASH9_PBKDF_OUTPUT_LEN);
}
}
|
