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lax_der_privatekey_parsing.c
Go to the documentation of this file.
1/***********************************************************************
2 * Copyright (c) 2014, 2015 Pieter Wuille *
3 * Distributed under the MIT software license, see the accompanying *
4 * file COPYING or https://www.opensource.org/licenses/mit-license.php.*
5 ***********************************************************************/
6
7#include <string.h>
8#include <secp256k1.h>
9
11
12int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *out32, const unsigned char *privkey, size_t privkeylen) {
13 const unsigned char *end = privkey + privkeylen;
14 int lenb = 0;
15 int len = 0;
16 memset(out32, 0, 32);
17 /* sequence header */
18 if (end < privkey+1 || *privkey != 0x30) {
19 return 0;
20 }
21 privkey++;
22 /* sequence length constructor */
23 if (end < privkey+1 || !(*privkey & 0x80)) {
24 return 0;
25 }
26 lenb = *privkey & ~0x80; privkey++;
27 if (lenb < 1 || lenb > 2) {
28 return 0;
29 }
30 if (end < privkey+lenb) {
31 return 0;
32 }
33 /* sequence length */
34 len = privkey[lenb-1] | (lenb > 1 ? privkey[lenb-2] << 8 : 0);
35 privkey += lenb;
36 if (end < privkey+len) {
37 return 0;
38 }
39 /* sequence element 0: version number (=1) */
40 if (end < privkey+3 || privkey[0] != 0x02 || privkey[1] != 0x01 || privkey[2] != 0x01) {
41 return 0;
42 }
43 privkey += 3;
44 /* sequence element 1: octet string, up to 32 bytes */
45 if (end < privkey+2 || privkey[0] != 0x04 || privkey[1] > 0x20 || end < privkey+2+privkey[1]) {
46 return 0;
47 }
48 memcpy(out32 + 32 - privkey[1], privkey + 2, privkey[1]);
50 memset(out32, 0, 32);
51 return 0;
52 }
53 return 1;
54}
55
56int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed) {
57 secp256k1_pubkey pubkey;
58 size_t pubkeylen = 0;
59 if (!secp256k1_ec_pubkey_create(ctx, &pubkey, key32)) {
60 *privkeylen = 0;
61 return 0;
62 }
63 if (compressed) {
64 static const unsigned char begin[] = {
65 0x30,0x81,0xD3,0x02,0x01,0x01,0x04,0x20
66 };
67 static const unsigned char middle[] = {
68 0xA0,0x81,0x85,0x30,0x81,0x82,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
69 0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
70 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
71 0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
72 0x21,0x02,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
73 0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
74 0x17,0x98,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
75 0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
76 0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x24,0x03,0x22,0x00
77 };
78 unsigned char *ptr = privkey;
79 memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
80 memcpy(ptr, key32, 32); ptr += 32;
81 memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
82 pubkeylen = 33;
84 ptr += pubkeylen;
85 *privkeylen = ptr - privkey;
86 } else {
87 static const unsigned char begin[] = {
88 0x30,0x82,0x01,0x13,0x02,0x01,0x01,0x04,0x20
89 };
90 static const unsigned char middle[] = {
91 0xA0,0x81,0xA5,0x30,0x81,0xA2,0x02,0x01,0x01,0x30,0x2C,0x06,0x07,0x2A,0x86,0x48,
92 0xCE,0x3D,0x01,0x01,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
93 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
94 0xFF,0xFF,0xFE,0xFF,0xFF,0xFC,0x2F,0x30,0x06,0x04,0x01,0x00,0x04,0x01,0x07,0x04,
95 0x41,0x04,0x79,0xBE,0x66,0x7E,0xF9,0xDC,0xBB,0xAC,0x55,0xA0,0x62,0x95,0xCE,0x87,
96 0x0B,0x07,0x02,0x9B,0xFC,0xDB,0x2D,0xCE,0x28,0xD9,0x59,0xF2,0x81,0x5B,0x16,0xF8,
97 0x17,0x98,0x48,0x3A,0xDA,0x77,0x26,0xA3,0xC4,0x65,0x5D,0xA4,0xFB,0xFC,0x0E,0x11,
98 0x08,0xA8,0xFD,0x17,0xB4,0x48,0xA6,0x85,0x54,0x19,0x9C,0x47,0xD0,0x8F,0xFB,0x10,
99 0xD4,0xB8,0x02,0x21,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
100 0xFF,0xFF,0xFF,0xFF,0xFE,0xBA,0xAE,0xDC,0xE6,0xAF,0x48,0xA0,0x3B,0xBF,0xD2,0x5E,
101 0x8C,0xD0,0x36,0x41,0x41,0x02,0x01,0x01,0xA1,0x44,0x03,0x42,0x00
102 };
103 unsigned char *ptr = privkey;
104 memcpy(ptr, begin, sizeof(begin)); ptr += sizeof(begin);
105 memcpy(ptr, key32, 32); ptr += 32;
106 memcpy(ptr, middle, sizeof(middle)); ptr += sizeof(middle);
107 pubkeylen = 65;
109 ptr += pubkeylen;
110 *privkeylen = ptr - privkey;
111 }
112 return 1;
113}
secp256k1_context * ctx
int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed)
Export a private key in DER format.
int ec_privkey_import_der(const secp256k1_context *ctx, unsigned char *out32, const unsigned char *privkey, size_t privkeylen)
Import a private key in DER format.
T GetRand(T nMax=std::numeric_limits< T >::max()) noexcept
Generate a uniform random integer of type T in the range [0..nMax) nMax defaults to std::numeric_limi...
Definition random.h:85
SECP256K1_API int secp256k1_ec_pubkey_serialize(const secp256k1_context *ctx, unsigned char *output, size_t *outputlen, const secp256k1_pubkey *pubkey, unsigned int flags) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4)
Serialize a pubkey object into a serialized byte sequence.
Definition secp256k1.c:296
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_seckey_verify(const secp256k1_context *ctx, const unsigned char *seckey) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2)
Verify an ECDSA secret key.
Definition secp256k1.c:550
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_create(const secp256k1_context *ctx, secp256k1_pubkey *pubkey, const unsigned char *seckey) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3)
Compute the public key for a secret key.
Definition secp256k1.c:573
#define SECP256K1_EC_COMPRESSED
Flag to pass to secp256k1_ec_pubkey_serialize.
Definition secp256k1.h:176
#define SECP256K1_EC_UNCOMPRESSED
Definition secp256k1.h:177
Opaque data structure that holds a parsed and valid public key.
Definition secp256k1.h:67