forked from bitcoin/bitcoin
-
Notifications
You must be signed in to change notification settings - Fork 5
/
secp256k1_extrakeys.h
249 lines (232 loc) · 10.8 KB
/
secp256k1_extrakeys.h
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
#ifndef SECP256K1_EXTRAKEYS_H
#define SECP256K1_EXTRAKEYS_H
#include "secp256k1.h"
#ifdef __cplusplus
extern "C" {
#endif
/** Opaque data structure that holds a parsed and valid "x-only" public key.
* An x-only pubkey encodes a point whose Y coordinate is even. It is
* serialized using only its X coordinate (32 bytes). See BIP-340 for more
* information about x-only pubkeys.
*
* The exact representation of data inside is implementation defined and not
* guaranteed to be portable between different platforms or versions. It is
* however guaranteed to be 64 bytes in size, and can be safely copied/moved.
* If you need to convert to a format suitable for storage, transmission, use
* use secp256k1_xonly_pubkey_serialize and secp256k1_xonly_pubkey_parse. To
* compare keys, use secp256k1_xonly_pubkey_cmp.
*/
typedef struct {
unsigned char data[64];
} secp256k1_xonly_pubkey;
/** Opaque data structure that holds a keypair consisting of a secret and a
* public key.
*
* The exact representation of data inside is implementation defined and not
* guaranteed to be portable between different platforms or versions. It is
* however guaranteed to be 96 bytes in size, and can be safely copied/moved.
*/
typedef struct {
unsigned char data[96];
} secp256k1_keypair;
/** Parse a 32-byte sequence into a xonly_pubkey object.
*
* Returns: 1 if the public key was fully valid.
* 0 if the public key could not be parsed or is invalid.
*
* Args: ctx: a secp256k1 context object.
* Out: pubkey: pointer to a pubkey object. If 1 is returned, it is set to a
* parsed version of input. If not, it's set to an invalid value.
* In: input32: pointer to a serialized xonly_pubkey.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_parse(
const secp256k1_context *ctx,
secp256k1_xonly_pubkey *pubkey,
const unsigned char *input32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Serialize an xonly_pubkey object into a 32-byte sequence.
*
* Returns: 1 always.
*
* Args: ctx: a secp256k1 context object.
* Out: output32: a pointer to a 32-byte array to place the serialized key in.
* In: pubkey: a pointer to a secp256k1_xonly_pubkey containing an initialized public key.
*/
SECP256K1_API int secp256k1_xonly_pubkey_serialize(
const secp256k1_context *ctx,
unsigned char *output32,
const secp256k1_xonly_pubkey *pubkey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Compare two x-only public keys using lexicographic order
*
* Returns: <0 if the first public key is less than the second
* >0 if the first public key is greater than the second
* 0 if the two public keys are equal
* Args: ctx: a secp256k1 context object.
* In: pubkey1: first public key to compare
* pubkey2: second public key to compare
*/
SECP256K1_API int secp256k1_xonly_pubkey_cmp(
const secp256k1_context *ctx,
const secp256k1_xonly_pubkey *pk1,
const secp256k1_xonly_pubkey *pk2
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Converts a secp256k1_pubkey into a secp256k1_xonly_pubkey.
*
* Returns: 1 always.
*
* Args: ctx: pointer to a context object.
* Out: xonly_pubkey: pointer to an x-only public key object for placing the converted public key.
* pk_parity: Ignored if NULL. Otherwise, pointer to an integer that
* will be set to 1 if the point encoded by xonly_pubkey is
* the negation of the pubkey and set to 0 otherwise.
* In: pubkey: pointer to a public key that is converted.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_from_pubkey(
const secp256k1_context *ctx,
secp256k1_xonly_pubkey *xonly_pubkey,
int *pk_parity,
const secp256k1_pubkey *pubkey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
/** Tweak an x-only public key by adding the generator multiplied with tweak32
* to it.
*
* Note that the resulting point can not in general be represented by an x-only
* pubkey because it may have an odd Y coordinate. Instead, the output_pubkey
* is a normal secp256k1_pubkey.
*
* Returns: 0 if the arguments are invalid or the resulting public key would be
* invalid (only when the tweak is the negation of the corresponding
* secret key). 1 otherwise.
*
* Args: ctx: pointer to a context object.
* Out: output_pubkey: pointer to a public key to store the result. Will be set
* to an invalid value if this function returns 0.
* In: internal_pubkey: pointer to an x-only pubkey to apply the tweak to.
* tweak32: pointer to a 32-byte tweak, which must be valid
* according to secp256k1_ec_seckey_verify or 32 zero
* bytes. For uniformly random 32-byte tweaks, the chance of
* being invalid is negligible (around 1 in 2^128).
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_tweak_add(
const secp256k1_context *ctx,
secp256k1_pubkey *output_pubkey,
const secp256k1_xonly_pubkey *internal_pubkey,
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
/** Checks that a tweaked pubkey is the result of calling
* secp256k1_xonly_pubkey_tweak_add with internal_pubkey and tweak32.
*
* The tweaked pubkey is represented by its 32-byte x-only serialization and
* its pk_parity, which can both be obtained by converting the result of
* tweak_add to a secp256k1_xonly_pubkey.
*
* Note that this alone does _not_ verify that the tweaked pubkey is a
* commitment. If the tweak is not chosen in a specific way, the tweaked pubkey
* can easily be the result of a different internal_pubkey and tweak.
*
* Returns: 0 if the arguments are invalid or the tweaked pubkey is not the
* result of tweaking the internal_pubkey with tweak32. 1 otherwise.
* Args: ctx: pointer to a context object.
* In: tweaked_pubkey32: pointer to a serialized xonly_pubkey.
* tweaked_pk_parity: the parity of the tweaked pubkey (whose serialization
* is passed in as tweaked_pubkey32). This must match the
* pk_parity value that is returned when calling
* secp256k1_xonly_pubkey with the tweaked pubkey, or
* this function will fail.
* internal_pubkey: pointer to an x-only public key object to apply the tweak to.
* tweak32: pointer to a 32-byte tweak.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_xonly_pubkey_tweak_add_check(
const secp256k1_context *ctx,
const unsigned char *tweaked_pubkey32,
int tweaked_pk_parity,
const secp256k1_xonly_pubkey *internal_pubkey,
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4) SECP256K1_ARG_NONNULL(5);
/** Compute the keypair for a secret key.
*
* Returns: 1: secret was valid, keypair is ready to use
* 0: secret was invalid, try again with a different secret
* Args: ctx: pointer to a context object (not secp256k1_context_static).
* Out: keypair: pointer to the created keypair.
* In: seckey: pointer to a 32-byte secret key.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_create(
const secp256k1_context *ctx,
secp256k1_keypair *keypair,
const unsigned char *seckey
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Get the secret key from a keypair.
*
* Returns: 1 always.
* Args: ctx: pointer to a context object.
* Out: seckey: pointer to a 32-byte buffer for the secret key.
* In: keypair: pointer to a keypair.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_sec(
const secp256k1_context *ctx,
unsigned char *seckey,
const secp256k1_keypair *keypair
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Get the public key from a keypair.
*
* Returns: 1 always.
* Args: ctx: pointer to a context object.
* Out: pubkey: pointer to a pubkey object. If 1 is returned, it is set to
* the keypair public key. If not, it's set to an invalid value.
* In: keypair: pointer to a keypair.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_pub(
const secp256k1_context *ctx,
secp256k1_pubkey *pubkey,
const secp256k1_keypair *keypair
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
/** Get the x-only public key from a keypair.
*
* This is the same as calling secp256k1_keypair_pub and then
* secp256k1_xonly_pubkey_from_pubkey.
*
* Returns: 1 always.
* Args: ctx: pointer to a context object.
* Out: pubkey: pointer to an xonly_pubkey object. If 1 is returned, it is set
* to the keypair public key after converting it to an
* xonly_pubkey. If not, it's set to an invalid value.
* pk_parity: Ignored if NULL. Otherwise, pointer to an integer that will be set to the
* pk_parity argument of secp256k1_xonly_pubkey_from_pubkey.
* In: keypair: pointer to a keypair.
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_xonly_pub(
const secp256k1_context *ctx,
secp256k1_xonly_pubkey *pubkey,
int *pk_parity,
const secp256k1_keypair *keypair
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(4);
/** Tweak a keypair by adding tweak32 to the secret key and updating the public
* key accordingly.
*
* Calling this function and then secp256k1_keypair_pub results in the same
* public key as calling secp256k1_keypair_xonly_pub and then
* secp256k1_xonly_pubkey_tweak_add.
*
* Returns: 0 if the arguments are invalid or the resulting keypair would be
* invalid (only when the tweak is the negation of the keypair's
* secret key). 1 otherwise.
*
* Args: ctx: pointer to a context object.
* In/Out: keypair: pointer to a keypair to apply the tweak to. Will be set to
* an invalid value if this function returns 0.
* In: tweak32: pointer to a 32-byte tweak, which must be valid according to
* secp256k1_ec_seckey_verify or 32 zero bytes. For uniformly
* random 32-byte tweaks, the chance of being invalid is
* negligible (around 1 in 2^128).
*/
SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_xonly_tweak_add(
const secp256k1_context *ctx,
secp256k1_keypair *keypair,
const unsigned char *tweak32
) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
#ifdef __cplusplus
}
#endif
#endif /* SECP256K1_EXTRAKEYS_H */