gaspersic/go-ethereum
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

crypto, crypto/secp256k1: add CompressPubkey (#15626)

Browse Source 
This adds the inverse to DecompressPubkey and improves a few minor
details in crypto/secp256k1.
This commit is contained in:
Felix Lange
2017-12-15 10:40:09 +01:00
committed by GitHub
parent 1f2176dedc
commit c6069a627c
6 changed files with 118 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
crypto/secp256k1/ext.h
View File

@ -19,7 +19,7 @@ static secp256k1_context* secp256k1_context_create_sign_verify() {
return secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
}
// secp256k1_ecdsa_recover_pubkey recovers the public key of an encoded compact signature.
// secp256k1_ext_ecdsa_recover recovers the public key of an encoded compact signature.
//
// Returns: 1: recovery was successful
// 0: recovery was not successful
@ -27,7 +27,7 @@ static secp256k1_context* secp256k1_context_create_sign_verify() {
// Out: pubkey_out: the serialized 65-byte public key of the signer (cannot be NULL)
// In: sigdata: pointer to a 65-byte signature with the recovery id at the end (cannot be NULL)
// msgdata: pointer to a 32-byte message (cannot be NULL)
static int secp256k1_ecdsa_recover_pubkey(
static int secp256k1_ext_ecdsa_recover(
const secp256k1_context* ctx,
unsigned char *pubkey_out,
const unsigned char *sigdata,
@ -46,7 +46,7 @@ static int secp256k1_ecdsa_recover_pubkey(
return secp256k1_ec_pubkey_serialize(ctx, pubkey_out, &outputlen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
}
// secp256k1_ecdsa_verify_enc verifies an encoded compact signature.
// secp256k1_ext_ecdsa_verify verifies an encoded compact signature.
//
// Returns: 1: signature is valid
// 0: signature is invalid
@ -55,7 +55,7 @@ static int secp256k1_ecdsa_recover_pubkey(
// msgdata: pointer to a 32-byte message (cannot be NULL)
// pubkeydata: pointer to public key data (cannot be NULL)
// pubkeylen: length of pubkeydata
static int secp256k1_ecdsa_verify_enc(
static int secp256k1_ext_ecdsa_verify(
const secp256k1_context* ctx,
const unsigned char *sigdata,
const unsigned char *msgdata,
@ -74,28 +74,34 @@ static int secp256k1_ecdsa_verify_enc(
return secp256k1_ecdsa_verify(ctx, &sig, msgdata, &pubkey);
}
// secp256k1_decompress_pubkey decompresses a public key.
// secp256k1_ext_reencode_pubkey decodes then encodes a public key. It can be used to
// convert between public key formats. The input/output formats are chosen depending on the
// length of the input/output buffers.
//
// Returns: 1: public key is valid
// 0: public key is invalid
// Returns: 1: conversion successful
// 0: conversion unsuccessful
// Args: ctx: pointer to a context object (cannot be NULL)
// Out: pubkey_out: the serialized 65-byte public key (cannot be NULL)
// In: pubkeydata: pointer to 33 bytes of compressed public key data (cannot be NULL)
static int secp256k1_decompress_pubkey(
// Out: out: output buffer that will contain the reencoded key (cannot be NULL)
// In: outlen: length of out (33 for compressed keys, 65 for uncompressed keys)
// pubkeydata: the input public key (cannot be NULL)
// pubkeylen: length of pubkeydata
static int secp256k1_ext_reencode_pubkey(
const secp256k1_context* ctx,
unsigned char *pubkey_out,
const unsigned char *pubkeydata
unsigned char *out,
size_t outlen,
const unsigned char *pubkeydata,
size_t pubkeylen
) {
secp256k1_pubkey pubkey;
if (!secp256k1_ec_pubkey_parse(ctx, &pubkey, pubkeydata, 33)) {
if (!secp256k1_ec_pubkey_parse(ctx, &pubkey, pubkeydata, pubkeylen)) {
return 0;
}
size_t outputlen = 65;
return secp256k1_ec_pubkey_serialize(ctx, pubkey_out, &outputlen, &pubkey, SECP256K1_EC_UNCOMPRESSED);
unsigned int flag = (outlen == 33) ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED;
return secp256k1_ec_pubkey_serialize(ctx, out, &outlen, &pubkey, flag);
}
// secp256k1_pubkey_scalar_mul multiplies a point by a scalar in constant time.
// secp256k1_ext_scalar_mul multiplies a point by a scalar in constant time.
//
// Returns: 1: multiplication was successful
// 0: scalar was invalid (zero or overflow)
@ -104,7 +110,7 @@ static int secp256k1_decompress_pubkey(
// In: point: pointer to a 64-byte public point,
// encoded as two 256bit big-endian numbers.
// scalar: a 32-byte scalar with which to multiply the point
int secp256k1_pubkey_scalar_mul(const secp256k1_context* ctx, unsigned char *point, const unsigned char *scalar) {
int secp256k1_ext_scalar_mul(const secp256k1_context* ctx, unsigned char *point, const unsigned char *scalar) {
int ret = 0;
int overflow = 0;
secp256k1_fe feX, feY;