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
|
/*
* Nyberg-Rueppel
* (C) 1999-2010 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/pk_utils.h>
#include <botan/nr.h>
#include <botan/keypair.h>
#include <botan/reducer.h>
#include <future>
namespace Botan {
NR_PublicKey::NR_PublicKey(const AlgorithmIdentifier& alg_id,
const secure_vector<byte>& key_bits) :
DL_Scheme_PublicKey(alg_id, key_bits, DL_Group::ANSI_X9_57)
{
}
/*
* NR_PublicKey Constructor
*/
NR_PublicKey::NR_PublicKey(const DL_Group& grp, const BigInt& y1)
{
group = grp;
y = y1;
}
/*
* Create a NR private key
*/
NR_PrivateKey::NR_PrivateKey(RandomNumberGenerator& rng,
const DL_Group& grp,
const BigInt& x_arg)
{
group = grp;
x = x_arg;
if(x == 0)
x = BigInt::random_integer(rng, 2, group_q() - 1);
y = power_mod(group_g(), x, group_p());
if(x_arg == 0)
gen_check(rng);
else
load_check(rng);
}
NR_PrivateKey::NR_PrivateKey(const AlgorithmIdentifier& alg_id,
const secure_vector<byte>& key_bits,
RandomNumberGenerator& rng) :
DL_Scheme_PrivateKey(alg_id, key_bits, DL_Group::ANSI_X9_57)
{
y = power_mod(group_g(), x, group_p());
load_check(rng);
}
/*
* Check Private Nyberg-Rueppel Parameters
*/
bool NR_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const
{
if(!DL_Scheme_PrivateKey::check_key(rng, strong) || x >= group_q())
return false;
if(!strong)
return true;
return KeyPair::signature_consistency_check(rng, *this, "EMSA1(SHA-1)");
}
namespace {
/**
* Nyberg-Rueppel signature operation
*/
class NR_Signature_Operation : public PK_Ops::Signature
{
public:
typedef NR_PrivateKey Key_Type;
NR_Signature_Operation(const NR_PrivateKey& nr, const std::string&) :
q(nr.group_q()),
x(nr.get_x()),
powermod_g_p(nr.group_g(), nr.group_p()),
mod_q(nr.group_q())
{
}
size_t message_parts() const { return 2; }
size_t message_part_size() const { return q.bytes(); }
size_t max_input_bits() const { return (q.bits() - 1); }
secure_vector<byte> sign(const byte msg[], size_t msg_len,
RandomNumberGenerator& rng);
private:
const BigInt& q;
const BigInt& x;
Fixed_Base_Power_Mod powermod_g_p;
Modular_Reducer mod_q;
};
secure_vector<byte>
NR_Signature_Operation::sign(const byte msg[], size_t msg_len,
RandomNumberGenerator& rng)
{
rng.add_entropy(msg, msg_len);
BigInt f(msg, msg_len);
if(f >= q)
throw Invalid_Argument("NR_Signature_Operation: Input is out of range");
BigInt c, d;
while(c == 0)
{
BigInt k;
do
k.randomize(rng, q.bits());
while(k >= q);
c = mod_q.reduce(powermod_g_p(k) + f);
d = mod_q.reduce(k - x * c);
}
secure_vector<byte> output(2*q.bytes());
c.binary_encode(&output[output.size() / 2 - c.bytes()]);
d.binary_encode(&output[output.size() - d.bytes()]);
return output;
}
/**
* Nyberg-Rueppel verification operation
*/
class NR_Verification_Operation : public PK_Ops::Verification
{
public:
typedef NR_PublicKey Key_Type;
NR_Verification_Operation(const NR_PublicKey& nr, const std::string&) :
q(nr.group_q()), y(nr.get_y())
{
powermod_g_p = Fixed_Base_Power_Mod(nr.group_g(), nr.group_p());
powermod_y_p = Fixed_Base_Power_Mod(y, nr.group_p());
mod_p = Modular_Reducer(nr.group_p());
mod_q = Modular_Reducer(nr.group_q());
}
size_t message_parts() const { return 2; }
size_t message_part_size() const { return q.bytes(); }
size_t max_input_bits() const { return (q.bits() - 1); }
bool with_recovery() const { return true; }
secure_vector<byte> verify_mr(const byte msg[], size_t msg_len);
private:
const BigInt& q;
const BigInt& y;
Fixed_Base_Power_Mod powermod_g_p, powermod_y_p;
Modular_Reducer mod_p, mod_q;
};
secure_vector<byte>
NR_Verification_Operation::verify_mr(const byte msg[], size_t msg_len)
{
const BigInt& q = mod_q.get_modulus();
if(msg_len != 2*q.bytes())
throw Invalid_Argument("NR verification: Invalid signature");
BigInt c(msg, q.bytes());
BigInt d(msg + q.bytes(), q.bytes());
if(c.is_zero() || c >= q || d >= q)
throw Invalid_Argument("NR verification: Invalid signature");
auto future_y_c = std::async(std::launch::async, powermod_y_p, c);
BigInt g_d = powermod_g_p(d);
BigInt i = mod_p.multiply(g_d, future_y_c.get());
return BigInt::encode_locked(mod_q.reduce(c - i));
}
}
BOTAN_REGISTER_PK_SIGNATURE_OP("NR", NR_Signature_Operation);
BOTAN_REGISTER_PK_VERIFY_OP("NR", NR_Verification_Operation);
}
|
