Always create 70 byte signatures with low R values

When extra entropy is not specified by the caller, CKey::Sign will
now always create a signature that has a low R value and is at most
70 bytes. The resulting signature on the stack will be 71 bytes when
the sighash byte is included.

Using low R signatures means that the resulting DER encoded signature
will never need to have additional padding to account for high R
values.
This commit is contained in:
Andrew Chow
2018-07-14 16:03:28 -07:00
parent 9d86aad287
commit 18dfea0dd0
8 changed files with 70 additions and 22 deletions

View File

@@ -76,7 +76,7 @@ static void VerifyScriptBench(benchmark::State& state)
CMutableTransaction txSpend = BuildSpendingTransaction(scriptSig, txCredit);
CScriptWitness& witness = txSpend.vin[0].scriptWitness;
witness.stack.emplace_back();
key.Sign(SignatureHash(witScriptPubkey, txSpend, 0, SIGHASH_ALL, txCredit.vout[0].nValue, SigVersion::WITNESS_V0), witness.stack.back(), 0);
key.Sign(SignatureHash(witScriptPubkey, txSpend, 0, SIGHASH_ALL, txCredit.vout[0].nValue, SigVersion::WITNESS_V0), witness.stack.back());
witness.stack.back().push_back(static_cast<unsigned char>(SIGHASH_ALL));
witness.stack.push_back(ToByteVector(pubkey));