/// <summary>
/// Attaches the envelope.
/// </summary>
/// <param name="secp256k1">Secp256k1.</param>
/// <param name="pedersen">Pedersen.</param>
/// <param name="rangeProof">Range proof.</param>
/// <param name="blindSum">Blind sum.</param>
/// <param name="commitSum">Commit sum.</param>
/// <param name="secret">Secret.</param>
private void AttachEnvelope(Secp256k1 secp256k1, Pedersen pedersen, RangeProof rangeProof, byte[] blindSum, byte[] commitSum, ulong balance, SecureString secret)
{
var(k1, k2) = Split(blindSum, secret);
Coin().Envelope.Commitment = commitSum.ToHex();
Coin().Envelope.Proof = k2.ToHex();
Coin().Envelope.PublicKey = pedersen.ToPublicKey(pedersen.Commit(0, k1)).ToHex();
Coin().Hash = Hash(Coin()).ToHex();
Coin().Envelope.Signature = secp256k1.Sign(Coin().Hash.FromHex(), k1).ToHex();
proofStruct = rangeProof.Proof(0, balance, blindSum, commitSum, Coin().Hash.FromHex());
var isVerified = rangeProof.Verify(commitSum, proofStruct);
if (!isVerified)
{
throw new ArgumentOutOfRangeException(nameof(isVerified), "Range proof failed.");
}
}
/// <summary>
/// Builds the coin.
/// </summary>
/// <returns>The coin.</returns>
/// <param name="blindSum">Blind sum.</param>
/// <param name="commitPos">Commit position.</param>
/// <param name="commitNeg">Commit neg.</param>
private CoinDto BuildCoin(byte[] blindSum, byte[] commitPos, byte[] commitNeg, bool isReceiver = false)
{
Guard.Argument(blindSum, nameof(blindSum)).NotNull().MaxCount(32);
Guard.Argument(commitPos, nameof(commitPos)).NotNull().MaxCount(33);
Guard.Argument(commitNeg, nameof(commitNeg)).NotNull().MaxCount(33);
CoinDto coin = null;
bool isVerified;
using (var secp256k1 = new Secp256k1())
using (var pedersen = new Pedersen())
using (var rangeProof = new RangeProof())
{
try
{
var commitSum = pedersen.CommitSum(new List <byte[]> {
commitPos
}, new List <byte[]> {
commitNeg
});
var naTInput = NaT(Input());
var naTOutput = NaT(Output());
var naTChange = naTInput - naTOutput;
isVerified = isReceiver
? pedersen.VerifyCommitSum(new List <byte[]> {
commitPos, commitNeg
}, new List <byte[]> {
Commit(naTOutput, blindSum)
})
: pedersen.VerifyCommitSum(new List <byte[]> {
commitPos
}, new List <byte[]> {
commitNeg, commitSum
});
if (!isVerified)
{
throw new ArgumentOutOfRangeException(nameof(isVerified), "Verify commit sum failed.");
}
var(k1, k2) = Split(blindSum, isReceiver);
coin = MakeSingleCoin();
coin.Envelope.Commitment = isReceiver ? Commit(naTOutput, blindSum).ToHex() : commitSum.ToHex();
coin.Envelope.Proof = k2.ToHex();
coin.Envelope.PublicKey = pedersen.ToPublicKey(Commit(0, k1)).ToHex();
coin.Envelope.Signature = secp256k1.Sign(Hash(coin), k1).ToHex();
coin.Hash = Hash(coin).ToHex();
proofStruct = isReceiver
? rangeProof.Proof(0, naTOutput, blindSum, coin.Envelope.Commitment.FromHex(), coin.Hash.FromHex())
: rangeProof.Proof(0, naTChange, blindSum, coin.Envelope.Commitment.FromHex(), coin.Hash.FromHex());
isVerified = rangeProof.Verify(coin.Envelope.Commitment.FromHex(), proofStruct);
if (!isVerified)
{
throw new ArgumentOutOfRangeException(nameof(isVerified), "Range proof failed.");
}
}
catch (Exception ex)
{
logger.LogError($"Message: {ex.Message}\n Stack: {ex.StackTrace}");
}
}
return(coin);
}