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This commit is contained in:
Jack Grigg 2017-06-06 17:44:17 +12:00
parent a3603ac6f0
commit e181dbe748
No known key found for this signature in database
GPG Key ID: 665DBCD284F7DAFF
2 changed files with 29 additions and 0 deletions

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@ -17,6 +17,22 @@
static secp256k1_context* secp256k1_context_sign = NULL;
/** These functions are taken from the libsecp256k1 distribution and are very ugly. */
/**
* This parses a format loosely based on a DER encoding of the ECPrivateKey type from
* section C.4 of SEC 1 <http://www.secg.org/sec1-v2.pdf>, with the following caveats:
*
* * The octet-length of the SEQUENCE must be encoded as 1 or 2 octets. It is not
* required to be encoded as one octet if it is less than 256, as DER would require.
* * The octet-length of the SEQUENCE must not be greater than the remaining
* length of the key encoding, but need not match it (i.e. the encoding may contain
* junk after the encoded SEQUENCE).
* * The privateKey OCTET STRING is zero-filled on the left to 32 octets.
* * Anything after the encoding of the privateKey OCTET STRING is ignored, whether
* or not it is validly encoded DER.
*
* out32 must point to an output buffer of length at least 32 bytes.
*/
static int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *out32, const unsigned char *privkey, size_t privkeylen) {
const unsigned char *end = privkey + privkeylen;
size_t lenb = 0;
@ -66,6 +82,13 @@ static int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *ou
return 1;
}
/**
* This serializes to a DER encoding of the ECPrivateKey type from section C.4 of SEC 1
* <http://www.secg.org/sec1-v2.pdf>. The optional parameters and publicKey fields are
* included.
*
* key32 must point to a 32-byte raw private key.
*/
static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed) {
secp256k1_pubkey pubkey;
size_t pubkeylen = 0;

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@ -174,7 +174,13 @@ bool static IsLowDERSignature(const valtype &vchSig, ScriptError* serror) {
if (!IsValidSignatureEncoding(vchSig)) {
return set_error(serror, SCRIPT_ERR_SIG_DER);
}
// https://bitcoin.stackexchange.com/a/12556:
// Also note that inside transaction signatures, an extra hashtype byte
// follows the actual signature data.
std::vector<unsigned char> vchSigCopy(vchSig.begin(), vchSig.begin() + vchSig.size() - 1);
// If the S value is above the order of the curve divided by two, its
// complement modulo the order could have been used instead, which is
// one byte shorter when encoded correctly.
if (!CPubKey::CheckLowS(vchSigCopy)) {
return set_error(serror, SCRIPT_ERR_SIG_HIGH_S);
}