/// <summary>
/// Listing 3: Output splitting algorithm with input shuffling
/// Note: this is just a guess on what Listing 3 would like to describe as it's not clear. Examining the results it may well be correct.
/// https://www.comsys.rwth-aachen.de/fileadmin/papers/2017/2017-maurer-trustcom-coinjoin.pdf
/// </summary>
private SubSet MixTransactions2(SubSet tx1, SubSet tx2)
{
var allInputs = tx1.Inputs.Concat(tx2.Inputs);
var tx1InputsSum = tx1.Inputs.Sum(x => x.Value);
var tx2InputsSum = tx2.Inputs.Sum(x => x.Value);
var tx1OutputsSum = tx1.Outputs.Sum(x => x.Value);
var tx2OutputsSum = tx2.Outputs.Sum(x => x.Value);
if (tx1InputsSum.Almost(tx2InputsSum, Precision))
{
return(new SubSet(allInputs, tx1.Outputs.Concat(tx2.Outputs), Precision));
}
var combinations = allInputs.CombinationsWithoutRepetition();
var randomSum = combinations.RandomElement().Sum(x => x.Value);
while (randomSum >= tx1OutputsSum && randomSum >= tx2OutputsSum)
{
randomSum = combinations.RandomElement().Sum(x => x.Value);
}
IEnumerable <Coin> newOutputs;
if (tx1OutputsSum > randomSum)
{
newOutputs = RealizeSubSum(tx1.Outputs, randomSum).Concat(tx2.Outputs);
}
else
{
newOutputs = RealizeSubSum(tx2.Outputs, randomSum).Concat(tx1.Outputs);
}
return(new SubSet(allInputs, newOutputs, Precision));
}
/// <summary>
/// Listing 2: Simple output splitting algorithm
/// https://www.comsys.rwth-aachen.de/fileadmin/papers/2017/2017-maurer-trustcom-coinjoin.pdf
/// </summary>
private SubSet MixTransactions(SubSet tx1, SubSet tx2)
{
var allInputs = tx1.Inputs.Concat(tx2.Inputs);
var tx1InputsSum = tx1.Inputs.Sum(x => x.Value);
var tx2InputsSum = tx2.Inputs.Sum(x => x.Value);
if (tx1InputsSum.Almost(tx2InputsSum, Precision))
{
return(new SubSet(allInputs, tx1.Outputs.Concat(tx2.Outputs), Precision));
}
IEnumerable <Coin> newOutputs;
if (tx1InputsSum > tx2InputsSum)
{
var diff = tx1InputsSum - tx2InputsSum;
newOutputs = RealizeSubSum(tx1.Outputs, diff).Concat(tx2.Outputs);
}
else
{
var diff = tx2InputsSum - tx1InputsSum;
newOutputs = RealizeSubSum(tx2.Outputs, diff).Concat(tx1.Outputs);
}
return(new SubSet(allInputs, newOutputs, Precision));
}
/// <summary>
/// Create a non-derived mapping.
/// </summary>
public Mapping(SubSet subSet)
: this(new List <SubSet> {
subSet
})
{
}
