PRCYCoin  2.0.0.7rc1
P2P Digital Currency
eckey_impl.h
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1 /**********************************************************************
2  * Copyright (c) 2013, 2014 Pieter Wuille *
3  * Distributed under the MIT software license, see the accompanying *
4  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
5  **********************************************************************/
6 
7 #ifndef _SECP256K1_ECKEY_IMPL_H_
8 #define _SECP256K1_ECKEY_IMPL_H_
9 
10 #include "eckey.h"
11 
12 #include "scalar.h"
13 #include "field.h"
14 #include "group.h"
15 #include "ecmult_gen.h"
16 
17 static int secp256k1_eckey_pubkey_parse(secp256k1_ge_t *elem, const unsigned char *pub, int size) {
18  if (size == 33 && (pub[0] == 0x02 || pub[0] == 0x03)) {
19  secp256k1_fe_t x;
20  return secp256k1_fe_set_b32(&x, pub+1) && secp256k1_ge_set_xo(elem, &x, pub[0] == 0x03);
21  } else if (size == 65 && (pub[0] == 0x04 || pub[0] == 0x06 || pub[0] == 0x07)) {
22  secp256k1_fe_t x, y;
23  if (!secp256k1_fe_set_b32(&x, pub+1) || !secp256k1_fe_set_b32(&y, pub+33)) {
24  return 0;
25  }
26  secp256k1_ge_set_xy(elem, &x, &y);
27  if ((pub[0] == 0x06 || pub[0] == 0x07) && secp256k1_fe_is_odd(&y) != (pub[0] == 0x07))
28  return 0;
29  return secp256k1_ge_is_valid(elem);
30  } else {
31  return 0;
32  }
33 }
34 
35 static int secp256k1_eckey_pubkey_serialize(secp256k1_ge_t *elem, unsigned char *pub, int *size, int compressed) {
36  if (secp256k1_ge_is_infinity(elem)) {
37  return 0;
38  }
39  secp256k1_fe_normalize(&elem->x);
40  secp256k1_fe_normalize(&elem->y);
41  secp256k1_fe_get_b32(&pub[1], &elem->x);
42  if (compressed) {
43  *size = 33;
44  pub[0] = 0x02 | (secp256k1_fe_is_odd(&elem->y) ? 0x01 : 0x00);
45  } else {
46  *size = 65;
47  pub[0] = 0x04;
48  secp256k1_fe_get_b32(&pub[33], &elem->y);
49  }
50  return 1;
51 }
52 
53 static int secp256k1_eckey_privkey_parse(secp256k1_scalar_t *key, const unsigned char *privkey, int privkeylen) {
54  const unsigned char *end = privkey + privkeylen;
55  /* sequence header */
56  if (end < privkey+1 || *privkey != 0x30)
57  return 0;
58  privkey++;
59  /* sequence length constructor */
60  int lenb = 0;
61  if (end < privkey+1 || !(*privkey & 0x80))
62  return 0;
63  lenb = *privkey & ~0x80; privkey++;
64  if (lenb < 1 || lenb > 2)
65  return 0;
66  if (end < privkey+lenb)
67  return 0;
68  /* sequence length */
69  int len = 0;
70  len = privkey[lenb-1] | (lenb > 1 ? privkey[lenb-2] << 8 : 0);
71  privkey += lenb;
72  if (end < privkey+len)
73  return 0;
74  /* sequence element 0: version number (=1) */
75  if (end < privkey+3 || privkey[0] != 0x02 || privkey[1] != 0x01 || privkey[2] != 0x01)
76  return 0;
77  privkey += 3;
78  /* sequence element 1: octet string, up to 32 bytes */
79  if (end < privkey+2 || privkey[0] != 0x04 || privkey[1] > 0x20 || end < privkey+2+privkey[1])
80  return 0;
81  int overflow = 0;
82  unsigned char c[32] = {0};
83  memcpy(c + 32 - privkey[1], privkey + 2, privkey[1]);
84  secp256k1_scalar_set_b32(key, c, &overflow);
85  memset(c, 0, 32);
86  return !overflow;
87 }
88 
89 static int secp256k1_eckey_privkey_serialize(unsigned char *privkey, int *privkeylen, const secp256k1_scalar_t *key, int compressed) {
90  secp256k1_gej_t rp;
91  secp256k1_ecmult_gen(&rp, key);
92  secp256k1_ge_t r;
93  secp256k1_ge_set_gej(&r, &rp);
94  if (compressed) {
95  static const unsigned char begin[] = {
96  0x30,0x81,0xD3,0x02,0x01,0x01,0x04,0x20
97  };
98  static const unsigned char middle[] = {
99  0xA0,0x81,0x85,0x30,0x81,0x82,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
100  0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
101  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
102  0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
103  0x21,0x02,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
104  0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
105  0x17,0x98,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
106  0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
107  0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x24,0x03,0x22,0x00
108  };
109  unsigned char *ptr = privkey;
110  memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
111  secp256k1_scalar_get_b32(ptr, key); ptr += 32;
112  memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
113  int pubkeylen = 0;
114  if (!secp256k1_eckey_pubkey_serialize(&r, ptr, &pubkeylen, 1)) {
115  return 0;
116  }
117  ptr += pubkeylen;
118  *privkeylen = ptr - privkey;
119  } else {
120  static const unsigned char begin[] = {
121  0x30,0x82,0x01,0x13,0x02,0x01,0x01,0x04,0x20
122  };
123  static const unsigned char middle[] = {
124  0xA0,0x81,0xA5,0x30,0x81,0xA2,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
125  0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
126  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
127  0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
128  0x41,0x04,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
129  0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
130  0x17,0x98,0x48,0x3A,0xDA,0x77,0x26,0xA3,0xC4,0x65,0x5D,0xA4,0xFB,0xFC,0x0E,0x11,
131  0x08,0xA8,0xFD,0x17,0xB4,0x48,0xA6,0x85,0x54,0x19,0x9C,0x47,0xD0,0x8F,0xFB,0x10,
132  0xD4,0xB8,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
133  0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
134  0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x44,0x03,0x42,0x00
135  };
136  unsigned char *ptr = privkey;
137  memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
138  secp256k1_scalar_get_b32(ptr, key); ptr += 32;
139  memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
140  int pubkeylen = 0;
141  if (!secp256k1_eckey_pubkey_serialize(&r, ptr, &pubkeylen, 0)) {
142  return 0;
143  }
144  ptr += pubkeylen;
145  *privkeylen = ptr - privkey;
146  }
147  return 1;
148 }
149 
150 static int secp256k1_eckey_privkey_tweak_add(secp256k1_scalar_t *key, const secp256k1_scalar_t *tweak) {
151  secp256k1_scalar_add(key, key, tweak);
152  if (secp256k1_scalar_is_zero(key))
153  return 0;
154  return 1;
155 }
156 
157 static int secp256k1_eckey_pubkey_tweak_add(secp256k1_ge_t *key, const secp256k1_scalar_t *tweak) {
158  secp256k1_gej_t pt;
159  secp256k1_gej_set_ge(&pt, key);
160  secp256k1_scalar_t one;
161  secp256k1_scalar_set_int(&one, 1);
162  secp256k1_ecmult(&pt, &pt, &one, tweak);
163 
164  if (secp256k1_gej_is_infinity(&pt))
165  return 0;
166  secp256k1_ge_set_gej(key, &pt);
167  return 1;
168 }
169 
170 static int secp256k1_eckey_privkey_tweak_mul(secp256k1_scalar_t *key, const secp256k1_scalar_t *tweak) {
171  if (secp256k1_scalar_is_zero(tweak))
172  return 0;
173 
174  secp256k1_scalar_mul(key, key, tweak);
175  return 1;
176 }
177 
178 static int secp256k1_eckey_pubkey_tweak_mul(secp256k1_ge_t *key, const secp256k1_scalar_t *tweak) {
179  if (secp256k1_scalar_is_zero(tweak))
180  return 0;
181 
182  secp256k1_scalar_t zero;
183  secp256k1_scalar_set_int(&zero, 0);
184  secp256k1_gej_t pt;
185  secp256k1_gej_set_ge(&pt, key);
186  secp256k1_ecmult(&pt, &pt, tweak, &zero);
187  secp256k1_ge_set_gej(key, &pt);
188  return 1;
189 }
190 
191 #endif
secp256k1_gej_t
A group element of the secp256k1 curve, in jacobian coordinates.
Definition: group.h:21
memcpy
void * memcpy(void *a, const void *b, size_t c)
Definition: glibc_compat.cpp:15
secp256k1_ge_t::y
secp256k1_fe_t y
Definition: group.h:20
scalar.h
r
void const uint64_t uint64_t * r
Definition: field_5x52_asm_impl.h:10
group.h
ecmult_gen.h
secp256k1_fe_t
Definition: field_10x26.h:12
key
CKey key
Definition: bip38tooldialog.cpp:173
secp256k1_ge_t::x
secp256k1_fe_t x
Definition: group.h:19
eckey.h
secp256k1_scalar_t
A scalar modulo the group order of the secp256k1 curve.
Definition: scalar_4x64.h:13
secp256k1_ge_t
A group element of the secp256k1 curve, in affine coordinates.
Definition: group.h:14
field.h
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