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Deterministic signing

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This commit is contained in:
Pieter Wuille 2014-11-06 06:54:50 -08:00
parent 3060e36098
commit a53fd41485
4 changed files with 49 additions and 14 deletions
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29
src/key.cpp
View file

@ -5,6 +5,7 @@
#include "key.h"
#include "crypto/hmac_sha512.h"
#include "crypto/rfc6979_hmac_sha256.h"
#include "eccryptoverify.h"
#include "pubkey.h"
#include "random.h"
@ -71,19 +72,22 @@ CPubKey CKey::GetPubKey() const {
return result;
}
bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
bool CKey::Sign(const uint256 &hash, std::vector<unsigned char>& vchSig, uint32_t test_case) const {
if (!fValid)
return false;
vchSig.resize(72);
int nSigLen = 72;
CKey nonce;
RFC6979_HMAC_SHA256 prng(begin(), 32, (unsigned char*)&hash, 32);
do {
nonce.MakeNewKey(true);
if (secp256k1_ecdsa_sign((const unsigned char*)&hash, 32, (unsigned char*)&vchSig[0], &nSigLen, begin(), nonce.begin()))
break;
uint256 nonce;
prng.Generate((unsigned char*)&nonce, 32);
nonce += test_case;
int nSigLen = 72;
int ret = secp256k1_ecdsa_sign((const unsigned char*)&hash, 32, (unsigned char*)&vchSig[0], &nSigLen, begin(), (unsigned char*)&nonce);
vchSig.resize(nSigLen);
nonce = 0;
if (ret)
return true;
} while(true);
vchSig.resize(nSigLen);
return true;
}
bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig) const {
@ -91,10 +95,13 @@ bool CKey::SignCompact(const uint256 &hash, std::vector<unsigned char>& vchSig)
return false;
vchSig.resize(65);
int rec = -1;
CKey nonce;
RFC6979_HMAC_SHA256 prng(begin(), 32, (unsigned char*)&hash, 32);
do {
nonce.MakeNewKey(true);
if (secp256k1_ecdsa_sign_compact((const unsigned char*)&hash, 32, &vchSig[1], begin(), nonce.begin(), &rec))
uint256 nonce;
prng.Generate((unsigned char*)&nonce, 32);
int ret = secp256k1_ecdsa_sign_compact((const unsigned char*)&hash, 32, &vchSig[1], begin(), (unsigned char*)&nonce, &rec);
nonce = 0;
if (ret)
break;
} while(true);
assert(rec != -1);

8
src/key.h
View file

@ -121,8 +121,12 @@ public:
*/
CPubKey GetPubKey() const;
//! Create a DER-serialized signature.
bool Sign(const uint256& hash, std::vector<unsigned char>& vchSig) const;
/**
* Create a DER-serialized signature.
* The test_case parameter tweaks the deterministic nonce, and is only for
* testing. It should be zero for normal use.
*/
bool Sign(const uint256& hash, std::vector<unsigned char>& vchSig, uint32_t test_case = 0) const;
/**
* Create a compact signature (65 bytes), which allows reconstructing the used public key.

23
src/test/key_tests.cpp
View file

@ -8,6 +8,7 @@
#include "script/script.h"
#include "uint256.h"
#include "util.h"
#include "utilstrencodings.h"
#include <string>
#include <vector>
@ -142,6 +143,28 @@ BOOST_AUTO_TEST_CASE(key_test1)
BOOST_CHECK(rkey1C == pubkey1C);
BOOST_CHECK(rkey2C == pubkey2C);
}
// test deterministic signing
std::vector<unsigned char> detsig, detsigc;
string strMsg = "Very deterministic message";
uint256 hashMsg = Hash(strMsg.begin(), strMsg.end());
BOOST_CHECK(key1.Sign(hashMsg, detsig));
BOOST_CHECK(key1C.Sign(hashMsg, detsigc));
BOOST_CHECK(detsig == detsigc);
BOOST_CHECK(detsig == ParseHex("304402205dbbddda71772d95ce91cd2d14b592cfbc1dd0aabd6a394b6c2d377bbe59d31d022014ddda21494a4e221f0824f0b8b924c43fa43c0ad57dccdaa11f81a6bd4582f6"));
BOOST_CHECK(key2.Sign(hashMsg, detsig));
BOOST_CHECK(key2C.Sign(hashMsg, detsigc));
BOOST_CHECK(detsig == detsigc);
BOOST_CHECK(detsig == ParseHex("3044022052d8a32079c11e79db95af63bb9600c5b04f21a9ca33dc129c2bfa8ac9dc1cd5022061d8ae5e0f6c1a16bde3719c64c2fd70e404b6428ab9a69566962e8771b5944d"));
BOOST_CHECK(key1.SignCompact(hashMsg, detsig));
BOOST_CHECK(key1C.SignCompact(hashMsg, detsigc));
BOOST_CHECK(detsig == ParseHex("1c5dbbddda71772d95ce91cd2d14b592cfbc1dd0aabd6a394b6c2d377bbe59d31d14ddda21494a4e221f0824f0b8b924c43fa43c0ad57dccdaa11f81a6bd4582f6"));
BOOST_CHECK(detsigc == ParseHex("205dbbddda71772d95ce91cd2d14b592cfbc1dd0aabd6a394b6c2d377bbe59d31d14ddda21494a4e221f0824f0b8b924c43fa43c0ad57dccdaa11f81a6bd4582f6"));
BOOST_CHECK(key2.SignCompact(hashMsg, detsig));
BOOST_CHECK(key2C.SignCompact(hashMsg, detsigc));
BOOST_CHECK(detsig == ParseHex("1c52d8a32079c11e79db95af63bb9600c5b04f21a9ca33dc129c2bfa8ac9dc1cd561d8ae5e0f6c1a16bde3719c64c2fd70e404b6428ab9a69566962e8771b5944d"));
BOOST_CHECK(detsigc == ParseHex("2052d8a32079c11e79db95af63bb9600c5b04f21a9ca33dc129c2bfa8ac9dc1cd561d8ae5e0f6c1a16bde3719c64c2fd70e404b6428ab9a69566962e8771b5944d"));
}
BOOST_AUTO_TEST_SUITE_END()

3
src/test/script_tests.cpp
View file

@ -248,8 +248,9 @@ public:
{
uint256 hash = SignatureHash(scriptPubKey, spendTx, 0, nHashType);
std::vector<unsigned char> vchSig, r, s;
uint32_t iter = 0;
do {
key.Sign(hash, vchSig);
key.Sign(hash, vchSig, iter++);
if ((lenS == 33) != (vchSig[5 + vchSig[3]] == 33)) {
NegateSignatureS(vchSig);
}