public void Setup()
{
var keyBuffer = new byte[32];
_random.NextBytes(keyBuffer);
var key = new uint256(keyBuffer);
_testKey = key.ToBytes().Take(16).ToArray();
var builder = new GolombRiceFilterBuilder()
.SetKey(key)
.SetP(20);
var itemsInFilter = new List <byte[]>();
for (var j = 0; j < N; j++)
{
var data = new byte[_random.Next(20, 30)];
_random.NextBytes(data);
itemsInFilter.Add(data);
}
builder.AddEntries(itemsInFilter);
_sample = itemsInFilter.OrderBy(x => _random.Next()).Take(N / 200).ToArray();
_filter = builder.Build();
}
private FilterModel CreateFiltersWith(IEnumerable <byte[]> scripts)
{
var keyBuffer = new byte[32];
Random.NextBytes(keyBuffer);
var blockHash = new uint256(keyBuffer);
var builder = new GolombRiceFilterBuilder()
.SetKey(blockHash)
.SetP(20);
builder.AddEntries(scripts);
return(new FilterModel(
new SmartHeader(new uint256(blockHash), uint256.One, 0, DateTimeOffset.UtcNow),
builder.Build()));
}
private FilterModel CreateFiltersWith(IEnumerable <byte[]> scripts)
{
var keyBuffer = new byte[32];
Random.NextBytes(keyBuffer);
var blockHash = new uint256(keyBuffer);
var builder = new GolombRiceFilterBuilder()
.SetKey(blockHash)
.SetP(20);
builder.AddEntries(scripts);
return(new FilterModel
{
BlockHeight = 0,
BlockHash = new uint256(blockHash),
Filter = builder.Build()
});
}
public void Setup()
{
var random = new Random(Seed: 145);
var keyBuffer = new byte[32];
random.NextBytes(keyBuffer);
var key = new uint256(keyBuffer);
_builder = new GolombRiceFilterBuilder()
.SetKey(key)
.SetP(20);
_itemsInFilter = new List <byte[]>();
for (var j = 0; j < N; j++)
{
var data = new byte[random.Next(20, 30)];
random.NextBytes(data);
_itemsInFilter.Add(data);
}
_builder.AddEntries(_itemsInFilter);
}
public void FalsePositivesTest()
{
// Given this library can be used for building and query filters for each block of
// the bitcoin's blockchain, we must be sure it performs well, specially in the queries.
// Considering a 4MB block (overestimated) with an average transaction size of 250 bytes (underestimated)
// gives us 16000 transactions (this is about 27 tx/sec). Assuming 2.5 txouts per tx we have 83885 txouts
// per block.
const byte P = 20;
const int blockCount = 100;
const int maxBlockSize = 4_000_000;
const int avgTxSize = 250; // Currently the average is around 1kb.
const int txoutCountPerBlock = maxBlockSize / avgTxSize;
const int avgTxoutPushDataSize = 20; // P2PKH scripts has 20 bytes.
const int walletAddressCount = 1_000; // We estimate that our user will have 1000 addresses.
var key = Hashes.Hash256(new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 });
var testKey = key.ToBytes().SafeSubarray(0, 16);
// Generation of data to be added into the filter
var random = new Random();
var blocks = new List <BlockFilter>(blockCount);
for (var i = 0; i < blockCount; i++)
{
var builder = new GolombRiceFilterBuilder()
.SetKey(key)
.SetP(P);
var txouts = new List <byte[]>(txoutCountPerBlock);
for (var j = 0; j < txoutCountPerBlock; j++)
{
var pushDataBuffer = new byte[avgTxoutPushDataSize];
random.NextBytes(pushDataBuffer);
txouts.Add(pushDataBuffer);
}
builder.AddEntries(txouts);
var filter = builder.Build();
blocks.Add(new BlockFilter(filter, txouts));
}
var walletAddresses = new List <byte[]>(walletAddressCount);
var falsePositiveCount = 0;
for (var i = 0; i < walletAddressCount; i++)
{
var walletAddress = new byte[avgTxoutPushDataSize];
random.NextBytes(walletAddress);
walletAddresses.Add(walletAddress);
}
// Check that the filter can match every single txout in every block.
foreach (var block in blocks)
{
if (block.Filter.MatchAny(walletAddresses, testKey))
{
falsePositiveCount++;
}
}
Assert.True(falsePositiveCount < 5);
// Filter has to mat existing values
var falseNegativeCount = 0;
// Check that the filter can match every single txout in every block.
foreach (var block in blocks)
{
if (!block.Filter.MatchAny(block.Data, testKey))
{
falseNegativeCount++;
}
}
Assert.Equal(0, falseNegativeCount);
}