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
|
/*
* GOST 34.10-2001 implemenation
* (C) 2007 Falko Strenzke, FlexSecure GmbH
* Manuel Hartl, FlexSecure GmbH
* (C) 2008-2010 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/gost_3410.h>
#include <botan/numthry.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/secmem.h>
#include <botan/point_gfp.h>
namespace Botan {
X509_Encoder* GOST_3410_PublicKey::x509_encoder() const
{
class GOST_3410_Key_Encoder : public X509_Encoder
{
public:
AlgorithmIdentifier alg_id() const
{
return AlgorithmIdentifier(key->get_oid(),
key->domain().DER_encode(key->domain_format()));
}
MemoryVector<byte> key_bits() const
{
// Trust CryptoPro to come up with something obnoxious
const BigInt x = key->public_point().get_affine_x();
const BigInt y = key->public_point().get_affine_y();
SecureVector<byte> bits(2*std::max(x.bytes(), y.bytes()));
y.binary_encode(bits + (bits.size() / 2 - y.bytes()));
x.binary_encode(bits + (bits.size() - y.bytes()));
return DER_Encoder().encode(bits, OCTET_STRING).get_contents();
}
GOST_3410_Key_Encoder(const GOST_3410_PublicKey* k): key(k) {}
private:
const GOST_3410_PublicKey* key;
};
return new GOST_3410_Key_Encoder(this);
}
X509_Decoder* GOST_3410_PublicKey::x509_decoder()
{
class GOST_3410_Key_Decoder : public X509_Decoder
{
public:
void alg_id(const AlgorithmIdentifier& alg_id)
{
// Also includes hash and cipher OIDs... brilliant design guys
OID ecc_param_id;
BER_Decoder ber(alg_id.parameters);
ber.start_cons(SEQUENCE).decode(ecc_param_id);
key->domain_params = EC_Domain_Params(ecc_param_id);
}
void key_bits(const MemoryRegion<byte>& bits)
{
SecureVector<byte> key_bits;
BER_Decoder ber(bits);
ber.decode(key_bits, OCTET_STRING);
const u32bit part_size = key_bits.size() / 2;
BigInt y(key_bits, part_size);
BigInt x(key_bits + part_size, part_size);
const BigInt p = key->domain().get_curve().get_p();
key->public_key = PointGFp(key->domain().get_curve(), x, y);
key->X509_load_hook();
}
GOST_3410_Key_Decoder(GOST_3410_PublicKey* k): key(k) {}
private:
GOST_3410_PublicKey* key;
};
return new GOST_3410_Key_Decoder(this);
}
bool GOST_3410_PublicKey::verify(const byte msg[], u32bit msg_len,
const byte sig[], u32bit sig_len) const
{
const BigInt& n = domain().get_order();
if(sig_len != n.bytes()*2)
return false;
// NOTE: it is not checked whether the public point is set
if(domain().get_curve().get_p() == 0)
throw Internal_Error("domain parameters not set");
BigInt e(msg, msg_len);
BigInt r(sig, sig_len / 2);
BigInt s(sig + sig_len / 2, sig_len / 2);
if(r < 0 || r >= n || s < 0 || s >= n)
return false;
e %= n;
if(e == 0)
e = 1;
BigInt v = inverse_mod(e, n);
BigInt z1 = (s*v) % n;
BigInt z2 = (-r*v) % n;
PointGFp R = (z1 * domain().get_base_point() + z2 * public_point());
return (R.get_affine_x() == r);
}
GOST_3410_PublicKey::GOST_3410_PublicKey(const EC_Domain_Params& dom_par,
const PointGFp& pub_point)
{
domain_params = dom_par;
public_key = pub_point;
domain_encoding = EC_DOMPAR_ENC_EXPLICIT;
}
SecureVector<byte>
GOST_3410_PrivateKey::sign(const byte msg[],
u32bit msg_len,
RandomNumberGenerator& rng) const
{
const BigInt& n = domain().get_order();
BigInt k;
do
k.randomize(rng, n.bits()-1);
while(k >= n);
if(private_value() == 0)
throw Internal_Error("GOST_3410::sign(): no private key");
if(n == 0)
throw Internal_Error("GOST_3410::sign(): domain parameters not set");
BigInt e(msg, msg_len);
e %= n;
if(e == 0)
e = 1;
PointGFp k_times_P = domain().get_base_point() * k;
k_times_P.check_invariants();
BigInt r = k_times_P.get_affine_x() % n;
if(r == 0)
throw Internal_Error("GOST_3410::sign: r was zero");
BigInt s = (r*private_value() + k*e) % n;
SecureVector<byte> output(2*n.bytes());
r.binary_encode(output + (output.size() / 2 - r.bytes()));
s.binary_encode(output + (output.size() - s.bytes()));
return output;
}
}
|
