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Merge pull request #263

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99fd963 Add secp256k1_ec_pubkey_compress(), with test similar to the related decompress() function. (Thomas Kerin)
This commit is contained in:
Pieter Wuille
2015-07-13 20:53:04 -04:00
parent 4ab8990c52 99fd963bd5
commit 4fb174df08
3 changed files with 45 additions and 5 deletions
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15
src/secp256k1.c
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@@ -285,6 +285,21 @@ int secp256k1_ec_pubkey_decompress(const secp256k1_context_t* ctx, const unsigne
return ret;
}
int secp256k1_ec_pubkey_compress(const secp256k1_context_t* ctx, const unsigned char *pubkeyin, unsigned char *pubkeyout, int *pubkeylen) {
secp256k1_ge_t p;
int ret = 0;
DEBUG_CHECK(pubkeyin != NULL);
DEBUG_CHECK(pubkeyout != NULL);
DEBUG_CHECK(pubkeylen != NULL);
(void)ctx;
if (secp256k1_eckey_pubkey_parse(&p, pubkeyin, *pubkeylen)) {
ret = secp256k1_eckey_pubkey_serialize(&p, pubkeyout, pubkeylen, 1);
}
return ret;
}
int secp256k1_ec_privkey_tweak_add(const secp256k1_context_t* ctx, unsigned char *seckey, const unsigned char *tweak) {
secp256k1_scalar_t term;
secp256k1_scalar_t sec;

14
src/tests.c
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@@ -1614,14 +1614,22 @@ void test_ecdsa_end_to_end(void) {
CHECK(secp256k1_ec_pubkey_create(ctx, pubkey, &pubkeylen, privkey, (secp256k1_rand32() & 3) != 0) == 1);
if (secp256k1_rand32() & 1) {
unsigned char pubkey2[65] = {0};
int pubkey2len = pubkeylen;
unsigned char pubkey3RE[33] = {0};
int pubkey2len = pubkeylen, pubkey3len = pubkeylen;
/* Decompress into a new array */
CHECK(secp256k1_ec_pubkey_decompress(ctx, pubkey, pubkey2, &pubkey2len));
/* Compress into a new array */
CHECK(secp256k1_ec_pubkey_compress(ctx, pubkey, pubkey3RE, &pubkey3len));
/* Check that the key was changed iff it was originally compressed */
if (pubkeylen == 65) {
CHECK(memcmp(pubkey, pubkey2, 65) == 0);
CHECK(memcmp(pubkey, pubkey2, 65) == 0); /* Values should be the same */
CHECK(memcmp(pubkey3RE, pubkey, 33) != 0); /* Means it should have been compressed */
} else {
CHECK(memcmp(pubkey, pubkey2, 65) != 0);
CHECK(memcmp(pubkey, pubkey2, 65) != 0); /* Should have been decompressed */
CHECK(memcmp(pubkey3RE, pubkey, 33) == 0); /* Therefore compressed key should equal initial pubkey */
}
/* Decompress in place */
CHECK(secp256k1_ec_pubkey_decompress(ctx, pubkey, pubkey, &pubkeylen));