public PuzzleValue CheckCommitmentProof(ServerCommitmentsProof proof)
{
if (proof == null)
{
throw new ArgumentNullException(nameof(proof));
}
if (proof.FakeSolutions.Length != Parameters.FakeTransactionCount)
{
throw new ArgumentException("Expecting " + Parameters.FakeTransactionCount + " solutions");
}
if (proof.Quotients.Length != Parameters.RealTransactionCount - 1)
{
throw new ArgumentException("Expecting " + (Parameters.RealTransactionCount - 1) + " quotients");
}
AssertState(PromiseClientStates.WaitingCommitmentsProof);
var fakeHashes = _Hashes.OfType <FakeHash>().ToArray();
for (int i = 0; i < proof.FakeSolutions.Length; i++)
{
var fakeHash = fakeHashes[i];
var solution = proof.FakeSolutions[i];
if (solution._Value.CompareTo(Parameters.ServerKey._Key.Modulus) >= 0)
{
throw new PuzzleException("Solution bigger than modulus");
}
if (!new Puzzle(Parameters.ServerKey, fakeHash.Commitment.Puzzle).Verify(solution))
{
throw new PuzzleException("Invalid puzzle solution");
}
if (!IsValidSignature(solution, fakeHash, out ECDSASignature sig))
{
throw new PuzzleException("Invalid ECDSA signature");
}
}
var realHashes = _Hashes.OfType <RealHash>().ToArray();
for (int i = 1; i < Parameters.RealTransactionCount; i++)
{
var q = proof.Quotients[i - 1]._Value;
var p1 = realHashes[i - 1].Commitment.Puzzle._Value;
var p2 = realHashes[i].Commitment.Puzzle._Value;
var p22 = p1.Multiply(Parameters.ServerKey.Encrypt(q)).Mod(Parameters.ServerKey._Key.Modulus);
if (!p2.Equals(p22))
{
throw new PuzzleException("Invalid quotient");
}
}
_Hashes = _Hashes.OfType <RealHash>().ToArray(); // we do not need the fake one anymore
InternalState.FakeIndexes = null;
InternalState.Quotients = proof.Quotients;
var puzzleToSolve = _Hashes.OfType <RealHash>().First().Commitment.Puzzle;
BlindFactor blind = null;
var blindedPuzzle = new Puzzle(Parameters.ServerKey, puzzleToSolve).Blind(ref blind);
InternalState.BlindFactor = blind;
InternalState.Status = PromiseClientStates.Completed;
return(blindedPuzzle.PuzzleValue);
}
public PuzzleValue[] CheckCommitmentProof(ServerCommitmentsProof proof)
{
// steps 8, 10, 12
if (proof == null)
{
throw new ArgumentNullException(nameof(proof));
}
var FakeSolutionsCount = proof.FakeSolutions.Select(a => a.Length).Sum(); // sums the number of FakeSolutions.
if (FakeSolutionsCount != Parameters.GetTotalFakeTransactionsCount())
{
throw new ArgumentException($"Expecting {Parameters.GetTotalFakeTransactionsCount()} solutions");
}
var QuotientsCount = proof.Quotients.Select(a => a.Length).Sum(); // sums the number of Quotients.
if (QuotientsCount != (Parameters.GetTotalRealTransactionsCount() - _Parameters.PaymentsCount)) // this is Q * (mu - 1)
{
throw new ArgumentException($"Expecting {(Parameters.GetTotalRealTransactionsCount() - _Parameters.PaymentsCount)} quotients");
}
AssertState(PromiseClientStates.WaitingCommitmentsProof);
var previousSolutions = new byte[Parameters.FakeTransactionCountPerLevel][];
previousSolutions = previousSolutions.Select(a => new byte[0]).ToArray(); // Initialize to empty
for (int i = 0; i < _Hashes.Length; i++)
{
var fakeHashes = _Hashes[i].OfType <FakeHash>().ToArray();
for (int j = 0; j < fakeHashes.Length; j++)
{
// TODO: prove that the solutions are lined up in same order as the hashes.
var fakeHash = fakeHashes[j];
var solution = proof.FakeSolutions[i][j];
if (solution._Value.CompareTo(Parameters.ServerKey._Key.Modulus) >= 0)
{
throw new PuzzleException("Solution bigger than modulus");
}
if (!new Puzzle(Parameters.ServerKey, fakeHash.Commitment.Puzzle).Verify(solution))
{
throw new PuzzleException("Invalid puzzle solution");
}
previousSolutions[j] = Utils.Combine(solution.ToBytes(), previousSolutions[j]);
var paddedSolution = new PuzzleSolution(Utils.Combine(NBitcoin.Utils.ToBytes((uint)i, true), NBitcoin.Utils.ToBytes((uint)fakeHash.Index, true), previousSolutions[j]));
if (!IsValidSignature(paddedSolution, fakeHash, out ECDSASignature sig))
{
throw new PuzzleException("Invalid ECDSA signature");
}
}
}
// Step 10
for (int i = 0; i < _Hashes.Length; i++)
{
var realHashes = _Hashes[i].OfType <RealHash>().ToArray();
for (int j = 1; j < realHashes.Length; j++)
{
var q = proof.Quotients[i][j - 1]._Value;
var p1 = realHashes[j - 1].Commitment.Puzzle._Value;
var p2 = realHashes[j].Commitment.Puzzle._Value;
var p22 = p1.Multiply(Parameters.ServerKey.Encrypt(q)).Mod(Parameters.ServerKey._Key.Modulus);
if (!p2.Equals(p22))
{
throw new PuzzleException("Invalid quotient");
}
}
}
_Hashes = _Hashes.Select(a => a.OfType <RealHash>().ToArray()).ToArray(); // we do not need the fake one anymore
InternalState.FakeColumns = null;
InternalState.Quotients = proof.Quotients;
// Step 12
// Maybe move this step outside such that we can blind and send puzzles one by one.
BlindFactor[] blindFactors = new BlindFactor[_Hashes.Length];
PuzzleValue[] blindedPuzzles = new PuzzleValue[_Hashes.Length];
for (int i = 0; i < _Hashes.Length; i++)
{
var puzzleToSolve = _Hashes[i].OfType <RealHash>().First().Commitment.Puzzle;
blindedPuzzles[i] = new Puzzle(Parameters.ServerKey, puzzleToSolve).Blind(ref blindFactors[i]).PuzzleValue;
}
InternalState.BlindFactors = blindFactors;
InternalState.Status = PromiseClientStates.Completed;
return(blindedPuzzles);
}