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
|
/**
* (C) 2018 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/scrypt.h>
#include <botan/pbkdf2.h>
#include <botan/salsa20.h>
#include <botan/loadstor.h>
#include <botan/internal/bit_ops.h>
namespace Botan {
namespace {
void scryptBlockMix(size_t r, uint8_t* B, uint8_t* Y)
{
uint32_t B32[16];
secure_vector<uint8_t> X(64);
copy_mem(X.data(), &B[(2*r-1)*64], 64);
for(size_t i = 0; i != 2*r; i++)
{
xor_buf(X.data(), &B[64*i], 64);
load_le<uint32_t>(B32, X.data(), 16);
Salsa20::salsa_core(X.data(), B32, 8);
copy_mem(&Y[64*i], X.data(), 64);
}
for(size_t i = 0; i < r; ++i)
{
copy_mem(&B[i*64], &Y[(i * 2) * 64], 64);
}
for(size_t i = 0; i < r; ++i)
{
copy_mem(&B[(i + r) * 64], &Y[(i * 2 + 1) * 64], 64);
}
}
void scryptROMmix(size_t r, size_t N, uint8_t* B, secure_vector<uint8_t>& V)
{
const size_t S = 128 * r;
for(size_t i = 0; i != N; ++i)
{
copy_mem(&V[S*i], B, S);
scryptBlockMix(r, B, &V[N*S]);
}
for(size_t i = 0; i != N; ++i)
{
// compiler doesn't know here that N is power of 2
const size_t j = load_le<uint32_t>(&B[(2*r-1)*64], 0) & (N - 1);
xor_buf(B, &V[j*S], S);
scryptBlockMix(r, B, &V[N*S]);
}
}
}
Scrypt_Params::Scrypt_Params(size_t N, size_t r, size_t p) :
m_N(N), m_r(r), m_p(p)
{
BOTAN_ARG_CHECK(p <= 128, "Invalid scrypt p");
BOTAN_ARG_CHECK(N <= 4194304 && is_power_of_2(N), "Invalid scrypt N");
BOTAN_ARG_CHECK(r <= 64, "Invalid scrypt r");
}
Scrypt_Params::Scrypt_Params(std::chrono::milliseconds msec)
{
/*
This mapping is highly subjective and machine specific
For simplicity we fix r=8 and p=4
*/
m_r = 8;
m_p = 4;
if(msec.count() <= 10)
{
m_N = 4096;
m_p = 1;
}
else if(msec.count() <= 50)
{
m_N = 8192;
}
else if(msec.count() <= 100)
{
m_N = 16384;
}
else if(msec.count() <= 500)
{
m_N = 32768;
}
else
{
m_N = 65536;
}
}
Scrypt_Params::Scrypt_Params(size_t iterations)
{
// This mapping is highly subjective and machine specific
m_r = 8;
m_p = 4;
if(iterations < 1000)
{
m_N = 8192;
}
else if(iterations < 5000)
{
m_N = 16384;
}
else if(iterations < 10000)
{
m_N = 32768;
}
else
{
m_N = 65536;
}
}
void scrypt(uint8_t output[], size_t output_len,
const std::string& password,
const uint8_t salt[], size_t salt_len,
const Scrypt_Params& params)
{
scrypt(output, output_len, password, salt, salt_len,
params.N(), params.r(), params.p());
}
void scrypt(uint8_t output[], size_t output_len,
const std::string& password,
const uint8_t salt[], size_t salt_len,
size_t N, size_t r, size_t p)
{
// Upper bounds here are much lower than scrypt maximums yet seem sufficient
BOTAN_ARG_CHECK(p <= 128, "Invalid scrypt p");
BOTAN_ARG_CHECK(N <= 4194304 && is_power_of_2(N), "Invalid scrypt N");
BOTAN_ARG_CHECK(r <= 64, "Invalid scrypt r");
const size_t S = 128 * r;
secure_vector<uint8_t> B(p * S);
PKCS5_PBKDF2 pbkdf2(MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)").release());
pbkdf2.pbkdf(B.data(), B.size(),
password,
salt, salt_len,
1, std::chrono::milliseconds(0));
// temp space
secure_vector<uint8_t> V((N+1) * S);
// these can be parallel
for(size_t i = 0; i != p; ++i)
{
scryptROMmix(r, N, &B[128*r*i], V);
}
pbkdf2.pbkdf(output, output_len,
password,
B.data(), B.size(),
1, std::chrono::milliseconds(0));
}
}
|
