public void Deserialize(BinaryReader reader)
{
FiniteFieldPolynomial x, y;
DeserializeFrom(reader, out x, out y);
this.X = x;
this.Y = y;
}
public void Deserialize(BinaryReader reader)
{
FiniteFieldPolynomial x, y;
DeserializeFrom(reader, out x, out y);
this.X = x;
this.Y = y;
}
private static void DeserializeFrom(BinaryReader reader, out FiniteFieldPolynomial x, out FiniteFieldPolynomial y)
{
int x_i = (int)reader.ReadVarInt();
int expectedByteCount = (int)reader.ReadVarInt();
byte[] y_b = reader.ReadBytes(expectedByteCount);
IrreduciblePolynomial irp = new IrreduciblePolynomial(expectedByteCount * 8);
x = new FiniteFieldPolynomial(irp, x_i);
y = new FiniteFieldPolynomial(irp, y_b.ToBigIntegerFromBigEndianUnsignedBytes());
}
private static void DeserializeFrom(BinaryReader reader, out FiniteFieldPolynomial x, out FiniteFieldPolynomial y)
{
int x_i = (int)reader.ReadVarInt(int.MaxValue);
byte[] y_b = reader.ReadVarBytes();
IrreduciblePolynomial irp = new IrreduciblePolynomial(y_b.Length * 8);
x = new FiniteFieldPolynomial(irp, x_i);
y = new FiniteFieldPolynomial(irp, y_b.ToBigIntegerFromBigEndianUnsignedBytes());
}
private static void DeserializeFrom(BinaryReader reader, out FiniteFieldPolynomial x, out FiniteFieldPolynomial y)
{
int x_i = (int)reader.ReadVarInt();
int expectedByteCount = (int)reader.ReadVarInt();
byte[] y_b = reader.ReadBytes(expectedByteCount);
IrreduciblePolynomial irp = new IrreduciblePolynomial(expectedByteCount * 8);
x = new FiniteFieldPolynomial(irp, x_i);
y = new FiniteFieldPolynomial(irp, y_b.ToBigIntegerFromBigEndianUnsignedBytes());
}
private static FiniteFieldPoint AdjustPoint(int totalPoints, FiniteFieldPoint point)
{
var correction = new FiniteFieldPolynomial(point.Y.PrimePolynomial, BigInteger.One);
var correctionMultiplier = point.X;
for (int i = 1; i <= totalPoints; i++)
{
correction = correction * correctionMultiplier;
}
var newY = point.Y + correction;
return new FiniteFieldPoint(point.X, newY);
}
private static FiniteFieldPoint AdjustPoint(int totalPoints, FiniteFieldPoint point)
{
var correction = new FiniteFieldPolynomial(point.Y.PrimePolynomial, BigInteger.One);
var correctionMultiplier = point.X;
for (int i = 1; i <= totalPoints; i++)
{
correction = correction * correctionMultiplier;
}
var newY = point.Y + correction;
return(new FiniteFieldPoint(point.X, newY));
}
public static SplitSecret Split(byte[] secret, int threshold)
{
var irreduciblePolynomial = IrreduciblePolynomial.CreateOfByteSize(secret.Length);
var rawSecret = secret.ToBigIntegerFromBigEndianUnsignedBytes();
var diffusedSecret = DefaultDiffuser.Scramble(rawSecret, secret.Length);
var secretCoefficient = new FiniteFieldPolynomial(irreduciblePolynomial, diffusedSecret);
var allCoefficients = new[] { secretCoefficient }
.Concat(
GetRandomPolynomials(
irreduciblePolynomial,
threshold - 1)
)
.ToArray();
return new SplitSecret(threshold, irreduciblePolynomial, allCoefficients);
}
public static FiniteFieldPolynomial EvaluateAt(long x, FiniteFieldPolynomial[] coefficients)
{
// Use Horner's Scheme: http://en.wikipedia.org/wiki/Horner_scheme
FiniteFieldPolynomial xAsPoly = coefficients[0].GetValueInField(x);
// assume the coefficient for highest monomial is 1
FiniteFieldPolynomial result = xAsPoly.Clone();
for (int i = coefficients.Length - 1; i > 0; i--)
{
result = result + coefficients[i];
result = result * xAsPoly;
}
result = result + coefficients[0];
return result;
}
public static FiniteFieldPolynomial EvaluateAt(long x, FiniteFieldPolynomial[] coefficients)
{
// Use Horner's Scheme: http://en.wikipedia.org/wiki/Horner_scheme
FiniteFieldPolynomial xAsPoly = coefficients[0].GetValueInField(x);
// assume the coefficient for highest monomial is 1
FiniteFieldPolynomial result = xAsPoly.Clone();
for (int i = coefficients.Length - 1; i > 0; i--)
{
result = result + coefficients[i];
result = result * xAsPoly;
}
result = result + coefficients[0];
return(result);
}
public static bool TryParse(string s, out FiniteFieldPoint result)
{
var match = Regex.Match(s, @"(?<x>[0-9]+)-(?<y>[0-9a-fA-F]+)");
if (!match.Success)
{
result = null;
return(false);
}
try
{
var xString = match.Groups["x"].Value.ToLowerInvariant();
var yString = match.Groups["y"].Value.ToLowerInvariant();
// Each hex letter makes up 4 bits, so to get the degree in bits
// we multiply by 4
int polynomialDegree = yString.Length * 4;
var irp = new IrreduciblePolynomial(polynomialDegree);
var x = new FiniteFieldPolynomial(irp, BigInteger.Parse(xString));
// get bytes
var bigEndianBytes = new byte[yString.Length / 2];
for (int i = 0; i < yString.Length; i += 2)
{
bigEndianBytes[i / 2] = Byte.Parse(yString.Substring(i, 2), NumberStyles.HexNumber);
}
var y = new FiniteFieldPolynomial(irp, bigEndianBytes.ToBigIntegerFromBigEndianUnsignedBytes());
result = new FiniteFieldPoint(x, y);
return(true);
}
catch
{
result = null;
return(false);
}
}
public static bool TryParse(string s, out FiniteFieldPoint result)
{
var match = Regex.Match(s, @"(?<x>[0-9]+)-(?<y>[0-9a-fA-F]+)");
if (!match.Success)
{
result = null;
return false;
}
try
{
var xString = match.Groups["x"].Value.ToLowerInvariant();
var yString = match.Groups["y"].Value.ToLowerInvariant();
// Each hex letter makes up 4 bits, so to get the degree in bits
// we multiply by 4
int polynomialDegree = yString.Length * 4;
var irp = new IrreduciblePolynomial(polynomialDegree);
var x = new FiniteFieldPolynomial(irp, BigInteger.Parse(xString));
// get bytes
var bigEndianBytes = new byte[yString.Length / 2];
for (int i = 0; i < yString.Length; i += 2)
{
bigEndianBytes[i / 2] = Byte.Parse(yString.Substring(i, 2), NumberStyles.HexNumber);
}
var y = new FiniteFieldPolynomial(irp, bigEndianBytes.ToBigIntegerFromBigEndianUnsignedBytes());
result = new FiniteFieldPoint(x, y);
return true;
}
catch
{
result = null;
return false;
}
}
public FiniteFieldPoint GetShare(int n)
{
var xPoly = new FiniteFieldPolynomial(_IrreduciblePolynomial, new BigInteger(n));
var y = FiniteFieldPolynomial.EvaluateAt(n, _AllCoefficients);
return new FiniteFieldPoint(xPoly, y);
}
public FiniteFieldPoint(FiniteFieldPolynomial x, FiniteFieldPolynomial y)
{
X = x;
Y = y;
}
public FiniteFieldPoint(FiniteFieldPolynomial x, FiniteFieldPolynomial y)
{
X = x;
Y = y;
}
public void Deserialize(BinaryReader reader)
{
int x = (int)reader.ReadVarInt();
int expectedByteCount = (int)reader.ReadVarInt();
byte[] y = reader.ReadBytes(expectedByteCount);
IrreduciblePolynomial irp = new IrreduciblePolynomial(expectedByteCount * 8);
this.X = new FiniteFieldPolynomial(irp, x);
this.Y = new FiniteFieldPolynomial(irp, y.ToBigIntegerFromBigEndianUnsignedBytes());
}
public SplitSecret(int threshold, IrreduciblePolynomial irreduciblePolynomial, FiniteFieldPolynomial[] allCoefficients)
{
Threshold = threshold;
_IrreduciblePolynomial = irreduciblePolynomial;
_AllCoefficients = allCoefficients;
}
