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
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
|
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2011 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file license.txt or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_KEY_H
#define BITCOIN_KEY_H
#include <stdexcept>
#include <vector>
#include <openssl/ec.h>
#include <openssl/ecdsa.h>
#include <openssl/obj_mac.h>
#include "serialize.h"
#include "uint256.h"
// secp160k1
// const unsigned int PRIVATE_KEY_SIZE = 192;
// const unsigned int PUBLIC_KEY_SIZE = 41;
// const unsigned int SIGNATURE_SIZE = 48;
//
// secp192k1
// const unsigned int PRIVATE_KEY_SIZE = 222;
// const unsigned int PUBLIC_KEY_SIZE = 49;
// const unsigned int SIGNATURE_SIZE = 57;
//
// secp224k1
// const unsigned int PRIVATE_KEY_SIZE = 250;
// const unsigned int PUBLIC_KEY_SIZE = 57;
// const unsigned int SIGNATURE_SIZE = 66;
//
// secp256k1:
// const unsigned int PRIVATE_KEY_SIZE = 279;
// const unsigned int PUBLIC_KEY_SIZE = 65;
// const unsigned int SIGNATURE_SIZE = 72;
//
// see www.keylength.com
// script supports up to 75 for single byte push
int extern EC_KEY_regenerate_key(EC_KEY *eckey, BIGNUM *priv_key);
int extern ECDSA_SIG_recover_key_GFp(EC_KEY *eckey, ECDSA_SIG *ecsig, const unsigned char *msg, int msglen, int recid, int check);
class key_error : public std::runtime_error
{
public:
explicit key_error(const std::string& str) : std::runtime_error(str) {}
};
// secure_allocator is defined in serialize.h
// CPrivKey is a serialized private key, with all parameters included (279 bytes)
typedef std::vector<unsigned char, secure_allocator<unsigned char> > CPrivKey;
// CSecret is a serialization of just the secret parameter (32 bytes)
typedef std::vector<unsigned char, secure_allocator<unsigned char> > CSecret;
class CKey
{
protected:
EC_KEY* pkey;
bool fSet;
public:
CKey()
{
pkey = EC_KEY_new_by_curve_name(NID_secp256k1);
if (pkey == NULL)
throw key_error("CKey::CKey() : EC_KEY_new_by_curve_name failed");
fSet = false;
}
CKey(const CKey& b)
{
pkey = EC_KEY_dup(b.pkey);
if (pkey == NULL)
throw key_error("CKey::CKey(const CKey&) : EC_KEY_dup failed");
fSet = b.fSet;
}
CKey& operator=(const CKey& b)
{
if (!EC_KEY_copy(pkey, b.pkey))
throw key_error("CKey::operator=(const CKey&) : EC_KEY_copy failed");
fSet = b.fSet;
return (*this);
}
~CKey()
{
EC_KEY_free(pkey);
}
bool IsNull() const
{
return !fSet;
}
void MakeNewKey()
{
if (!EC_KEY_generate_key(pkey))
throw key_error("CKey::MakeNewKey() : EC_KEY_generate_key failed");
fSet = true;
}
bool SetPrivKey(const CPrivKey& vchPrivKey)
{
const unsigned char* pbegin = &vchPrivKey[0];
if (!d2i_ECPrivateKey(&pkey, &pbegin, vchPrivKey.size()))
return false;
fSet = true;
return true;
}
bool SetSecret(const CSecret& vchSecret)
{
EC_KEY_free(pkey);
pkey = EC_KEY_new_by_curve_name(NID_secp256k1);
if (pkey == NULL)
throw key_error("CKey::SetSecret() : EC_KEY_new_by_curve_name failed");
if (vchSecret.size() != 32)
throw key_error("CKey::SetSecret() : secret must be 32 bytes");
BIGNUM *bn = BN_bin2bn(&vchSecret[0],32,BN_new());
if (bn == NULL)
throw key_error("CKey::SetSecret() : BN_bin2bn failed");
if (!EC_KEY_regenerate_key(pkey,bn))
throw key_error("CKey::SetSecret() : EC_KEY_regenerate_key failed");
BN_clear_free(bn);
fSet = true;
return true;
}
CSecret GetSecret() const
{
CSecret vchRet;
vchRet.resize(32);
const BIGNUM *bn = EC_KEY_get0_private_key(pkey);
int nBytes = BN_num_bytes(bn);
if (bn == NULL)
throw key_error("CKey::GetSecret() : EC_KEY_get0_private_key failed");
int n=BN_bn2bin(bn,&vchRet[32 - nBytes]);
if (n != nBytes)
throw key_error("CKey::GetSecret(): BN_bn2bin failed");
return vchRet;
}
CPrivKey GetPrivKey() const
{
unsigned int nSize = i2d_ECPrivateKey(pkey, NULL);
if (!nSize)
throw key_error("CKey::GetPrivKey() : i2d_ECPrivateKey failed");
CPrivKey vchPrivKey(nSize, 0);
unsigned char* pbegin = &vchPrivKey[0];
if (i2d_ECPrivateKey(pkey, &pbegin) != nSize)
throw key_error("CKey::GetPrivKey() : i2d_ECPrivateKey returned unexpected size");
return vchPrivKey;
}
bool SetPubKey(const std::vector<unsigned char>& vchPubKey)
{
const unsigned char* pbegin = &vchPubKey[0];
if (!o2i_ECPublicKey(&pkey, &pbegin, vchPubKey.size()))
return false;
fSet = true;
return true;
}
std::vector<unsigned char> GetPubKey() const
{
unsigned int nSize = i2o_ECPublicKey(pkey, NULL);
if (!nSize)
throw key_error("CKey::GetPubKey() : i2o_ECPublicKey failed");
std::vector<unsigned char> vchPubKey(nSize, 0);
unsigned char* pbegin = &vchPubKey[0];
if (i2o_ECPublicKey(pkey, &pbegin) != nSize)
throw key_error("CKey::GetPubKey() : i2o_ECPublicKey returned unexpected size");
return vchPubKey;
}
bool Sign(uint256 hash, std::vector<unsigned char>& vchSig)
{
vchSig.clear();
unsigned char pchSig[10000];
unsigned int nSize = 0;
if (!ECDSA_sign(0, (unsigned char*)&hash, sizeof(hash), pchSig, &nSize, pkey))
return false;
vchSig.resize(nSize);
memcpy(&vchSig[0], pchSig, nSize);
return true;
}
// create a compact signature (65 bytes), which allows reconstructing the used public key
// The format is one header byte, followed by two times 32 bytes for the serialized r and s values.
// The header byte: 0x1B = first key with even y, 0x1C = first key with odd y,
// 0x1D = second key with even y, 0x1E = second key with odd y
bool SignCompact(uint256 hash, std::vector<unsigned char>& vchSig)
{
bool fOk = false;
ECDSA_SIG *sig = ECDSA_do_sign((unsigned char*)&hash, sizeof(hash), pkey);
if (sig==NULL)
return false;
vchSig.clear();
vchSig.resize(65,0);
int nBitsR = BN_num_bits(sig->r);
int nBitsS = BN_num_bits(sig->s);
if (nBitsR <= 256 && nBitsS <= 256)
{
int nRecId = -1;
for (int i=0; i<4; i++)
{
CKey keyRec;
keyRec.fSet = true;
if (ECDSA_SIG_recover_key_GFp(keyRec.pkey, sig, (unsigned char*)&hash, sizeof(hash), i, 1) == 1)
if (keyRec.GetPubKey() == this->GetPubKey())
{
nRecId = i;
break;
}
}
if (nRecId == -1)
throw key_error("CKey::SignCompact() : unable to construct recoverable key");
vchSig[0] = nRecId+27;
BN_bn2bin(sig->r,&vchSig[33-(nBitsR+7)/8]);
BN_bn2bin(sig->s,&vchSig[65-(nBitsS+7)/8]);
fOk = true;
}
ECDSA_SIG_free(sig);
return fOk;
}
// reconstruct public key from a compact signature
// This is only slightly more CPU intensive than just verifying it.
// If this function succeeds, the recovered public key is guaranteed to be valid
// (the signature is a valid signature of the given data for that key)
bool SetCompactSignature(uint256 hash, const std::vector<unsigned char>& vchSig)
{
if (vchSig.size() != 65)
return false;
if (vchSig[0]<27 || vchSig[0]>=31)
return false;
ECDSA_SIG *sig = ECDSA_SIG_new();
BN_bin2bn(&vchSig[1],32,sig->r);
BN_bin2bn(&vchSig[33],32,sig->s);
EC_KEY_free(pkey);
pkey = EC_KEY_new_by_curve_name(NID_secp256k1);
if (ECDSA_SIG_recover_key_GFp(pkey, sig, (unsigned char*)&hash, sizeof(hash), vchSig[0] - 27, 0) == 1)
{
fSet = true;
ECDSA_SIG_free(sig);
return true;
}
return false;
}
bool Verify(uint256 hash, const std::vector<unsigned char>& vchSig)
{
// -1 = error, 0 = bad sig, 1 = good
if (ECDSA_verify(0, (unsigned char*)&hash, sizeof(hash), &vchSig[0], vchSig.size(), pkey) != 1)
return false;
return true;
}
// Verify a compact signature
bool VerifyCompact(uint256 hash, const std::vector<unsigned char>& vchSig)
{
CKey key;
if (!key.SetCompactSignature(hash, vchSig))
return false;
if (GetPubKey() != key.GetPubKey())
return false;
return true;
}
};
#endif
|
