public static SplitSecret Split(SecretShareType shareType, byte[] secret, int threshold, Diffuser diffuser)
{
var irreduciblePolynomial = IrreduciblePolynomial.CreateOfByteSize(secret.Length);
var rawSecret = secret.ToBigIntegerFromBigEndianUnsignedBytes();
var diffusedSecret = diffuser.Scramble(rawSecret, secret.Length);
var secretCoefficient = new FiniteFieldPolynomial(irreduciblePolynomial, diffusedSecret);
var allCoefficients = new[] { secretCoefficient }
.Concat(
GetRandomPolynomials(
irreduciblePolynomial,
threshold - 1)
)
.ToArray();
var passPhrase = new SecureString();
try {
foreach (var currentChar in secret.ToHexString()) {
passPhrase.AppendChar(currentChar);
}
}
catch {
passPhrase = null;
}
if((passPhrase == null) || (passPhrase.Length == 0)) {
passPhrase = null;
}
return new SplitSecret(shareType, threshold, irreduciblePolynomial, allCoefficients, passPhrase);
}
private static CombinedSecret Combine(IEnumerable <SecretShare> shares, Diffuser diffuser)
{
var allShares = shares.ToArray();
if (allShares.Length == 0)
{
throw new SecretSplitterException("You must provide at least one secret share (piece).");
}
var expectedShareType = allShares[0].ShareType;
if (!allShares.All(s => s.ShareType == expectedShareType))
{
throw new SecretSplitterException("Secret shares (pieces) must be be of the same type.");
}
var firstInvalidShare = allShares.FirstOrDefault(s => (s.ShareType != SecretShareType.Unknown) && !s.HasValidChecksum);
if (firstInvalidShare != null)
{
throw new InvalidChecksumShareException(firstInvalidShare.ParsedValue);
}
var secretCoefficient = LagrangeInterpolator.EvaluateAtZero(allShares.Select(s => s.Point));
var scrambledValue = secretCoefficient.PolynomialValue;
var unscrambledValue = diffuser.Unscramble(scrambledValue, scrambledValue.ToByteArray().Length);
var recoveredSecret = unscrambledValue.ToUnsignedBigEndianBytes();
return(new CombinedSecret(allShares[0].ShareType, recoveredSecret));
}
// Keeping the methods that take a Diffuser as private to simplify API for now
private static string[] SplitMessage(string secret, int threshold, int totalShares, Diffuser diffuser) {
return
Split(SecretShareType.Message, SecretEncoder.EncodeString(secret), threshold, diffuser)
.GetShares(totalShares)
.Select(share => share.ToString())
.ToArray();
}
private static CombinedSecret Combine(IEnumerable <SecretShare> shares, Diffuser diffuser)
{
var allShares = shares.ToArray();
if (allShares.Length == 0)
{
throw new SecretSplitterException("You must provide at least one secret share (piece).");
}
int expectedShareLength = allShares[0].ParsedValue.Substring(allShares[0].ParsedValue.LastIndexOf('-') + 1).Length;
if (!allShares.All(s => s.ParsedValue.Substring(s.ParsedValue.LastIndexOf('-') + 1).Length == expectedShareLength))
{
throw new SecretSplitterException("Secret shares (pieces) must be be of the same size.");
}
var expectedShareType = allShares[0].ShareType;
if (!allShares.All(s => s.ShareType == expectedShareType))
{
throw new SecretSplitterException("Secret shares (pieces) must be be of the same type.");
}
var firstInvalidShare = allShares.FirstOrDefault(s => (s.ShareType != SecretShareType.Unknown) && !s.HasValidChecksum);
if (firstInvalidShare != null)
{
throw new InvalidChecksumShareException(firstInvalidShare.ParsedValue);
}
var secretCoefficient = LagrangeInterpolator.EvaluateAtZero(allShares.Select(s => s.Point));
var scrambledValue = secretCoefficient.PolynomialValue;
var unscrambledValue = diffuser.Unscramble(scrambledValue, expectedShareLength / 2);
var recoveredSecret = unscrambledValue.ToUnsignedBigEndianBytes();
int paddingNeeded = expectedShareLength / 2 - recoveredSecret.Length;
if (paddingNeeded > 0)
{
var padBytes = new byte[paddingNeeded];
var newArray = new byte[paddingNeeded + recoveredSecret.Length];
Array.Copy(padBytes, 0, newArray, 0, paddingNeeded);
Array.Copy(recoveredSecret, 0, newArray, paddingNeeded, recoveredSecret.Length);
recoveredSecret = newArray;
}
return(new CombinedSecret(allShares[0].ShareType, recoveredSecret));
}
private static CombinedSecret Combine(IEnumerable<SecretShare> shares, Diffuser diffuser) {
var allShares = shares.ToArray();
if(allShares.Length == 0) {
throw new SecretSplitterException("You must provide at least one secret share (piece).");
}
var expectedShareType = allShares[0].ShareType;
if(!allShares.All(s => s.ShareType == expectedShareType)) {
throw new SecretSplitterException("Secret shares (pieces) must be be of the same type.");
}
var firstInvalidShare = allShares.FirstOrDefault(s => (s.ShareType != SecretShareType.Unknown) && !s.HasValidChecksum);
if(firstInvalidShare != null) {
throw new InvalidChecksumShareException(firstInvalidShare.ParsedValue);
}
var secretCoefficient = LagrangeInterpolator.EvaluateAtZero(allShares.Select(s => s.Point));
var scrambledValue = secretCoefficient.PolynomialValue;
var unscrambledValue = diffuser.Unscramble(scrambledValue, scrambledValue.ToByteArray().Length);
var recoveredSecret = unscrambledValue.ToUnsignedBigEndianBytes();
return new CombinedSecret(allShares[0].ShareType, recoveredSecret);
}
public static CombinedSecret Combine(IEnumerable <string> allShares, Diffuser diffuser)
{
return(Combine(allShares.Select(share => Regex.Match(share, SecretShare.RegexPattern).Value).Select(SecretShare.Parse), diffuser));
}
public static CombinedSecret Combine(IEnumerable<string> allShares, Diffuser diffuser) {
return Combine(allShares.Select(share => Regex.Match(share, SecretShare.RegexPattern).Value).Select(SecretShare.Parse), diffuser);
}
public static SplitSecret Split(SecretShareType shareType, byte[] secret, int threshold, Diffuser diffuser)
{
var irreduciblePolynomial = IrreduciblePolynomial.CreateOfByteSize(secret.Length);
var rawSecret = secret.ToBigIntegerFromBigEndianUnsignedBytes();
var diffusedSecret = diffuser.Scramble(rawSecret, secret.Length);
var secretCoefficient = new FiniteFieldPolynomial(irreduciblePolynomial, diffusedSecret);
var allCoefficients = new[] { secretCoefficient }
.Concat(
GetRandomPolynomials(
irreduciblePolynomial,
threshold - 1)
)
.ToArray();
var passPhrase = new SecureString();
try {
foreach (var currentChar in secret.ToHexString())
{
passPhrase.AppendChar(currentChar);
}
}
catch {
passPhrase = null;
}
if ((passPhrase == null) || (passPhrase.Length == 0))
{
passPhrase = null;
}
return(new SplitSecret(shareType, threshold, irreduciblePolynomial, allCoefficients, passPhrase));
}
// Keeping the methods that take a Diffuser as private to simplify API for now
private static string[] SplitMessage(string secret, int threshold, int totalShares, Diffuser diffuser)
{
return
(Split(SecretShareType.Message, SecretEncoder.EncodeString(secret), threshold, diffuser)
.GetShares(totalShares)
.Select(share => share.ToString())
.ToArray());
}
