/// <summary>
/// Prepares the authority for voting procedure.
/// </summary>
/// <param name="index">Index given to this authority.</param>
/// <param name="parameters">Voting parameters for the procedure.</param>
public void Prepare(int index, Signed<VotingParameters> signedParameters)
{
if (index < 1)
throw new ArgumentException("Index must be at least 1.");
if (signedParameters == null)
throw new ArgumentNullException("signedParameters");
this.signedParameters = signedParameters;
this.parameters = signedParameters.Value;
this.authority = new Authority(index, this.parameters);
this.authority.CreatePolynomial();
this.authorities = new Dictionary<int, Certificate>();
}
/// <summary>
/// Load data of authority from file.
/// </summary>
/// <param name="fileName">Name of file to load.</param>
private void Load(string fileName)
{
FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read);
DeserializeContext context = new DeserializeContext(fileStream);
this.parameters = context.ReadObject<VotingParameters>();
this.signedParameters = context.ReadObject<Signed<VotingParameters>>();
this.authorities = new Dictionary<int,Certificate>();
int count = context.ReadInt32();
count.Times(() => this.authorities.Add(context.ReadInt32(), context.ReadObject<Certificate>()));
this.authority = new Authority(context, this.parameters);
context.Close();
fileStream.Close();
}
/// <summary>
/// Crypto base test.
/// </summary>
/// <remarks>
/// Only used during development.
/// </remarks>
public void BaseTest()
{
BigInt prime = Prime.Find(80);
BigInt safePrime = Prime.FindSafe(88);
BaseParameters parameters = new BaseParameters();
parameters.GenerateNumbers(Files.TestDataPath);
Question question = new Question(new MultiLanguageString(string.Empty), new MultiLanguageString(string.Empty), new MultiLanguageString(string.Empty), 1);
question.AddOption(new Option(new MultiLanguageString("Ja"), new MultiLanguageString(string.Empty), new MultiLanguageString(string.Empty)));
question.AddOption(new Option(new MultiLanguageString("Nein"), new MultiLanguageString(string.Empty), new MultiLanguageString(string.Empty)));
parameters.AddQuestion(question);
Authority[] auths = new Authority[5];
for (int aI = 0; aI < parameters.AuthorityCount; aI++)
{
auths[aI] = new Authority(aI + 1, parameters);
}
foreach (Authority a in auths)
{
a.CreatePolynomial();
}
foreach (Authority a in auths)
{
List<Share> shares = new List<Share>();
List<List<VerificationValue>> As = new List<List<VerificationValue>>();
foreach (Authority b in auths)
{
shares.Add(b.Share(a.Index));
As.Add(new List<VerificationValue>());
for (int l = 0; l <= parameters.Thereshold; l++)
{
As[As.Count - 1].Add(b.VerificationValue(l));
}
}
a.VerifySharing(shares, As);
}
BigInt publicKey = new BigInt(1);
foreach (Authority a in auths)
{
publicKey = (publicKey * a.PublicKeyPart).Mod(parameters.P);
}
List<Ballot> ballots = new List<Ballot>();
ballots.Add(new Ballot(new int[] { 0, 1 }, parameters, question, publicKey, null));
ballots.Add(new Ballot(new int[] { 0, 1 }, parameters, question, publicKey, null));
ballots.Add(new Ballot(new int[] { 1, 0 }, parameters, question, publicKey, null));
ballots.Add(new Ballot(new int[] { 0, 1 }, parameters, question, publicKey, null));
ballots.Add(new Ballot(new int[] { 1, 0 }, parameters, question, publicKey, null));
ballots.Add(new Ballot(new int[] { 0, 1 }, parameters, question, publicKey, null));
if (!ballots.All(ballot => ballot.Verify(publicKey, parameters, question, RandomNumberGenerator.Create(), BaseParameters.StandardProofCount, new Progress(null))))
throw new Exception("Bad proof.");
for (int optionIndex = 0; optionIndex < question.Options.Count(); optionIndex++)
{
IEnumerable<Vote> votes = ballots.Select(ballot => ballot.Votes[optionIndex]);
Vote sum = null;
votes.Foreach(vote => sum = sum == null ? vote : sum + vote);
List<PartialDecipher> partialDeciphers = new List<PartialDecipher>();
auths.Foreach(authority => partialDeciphers.AddRange(authority.PartialDeciphers(1, sum, 0, optionIndex)));
IEnumerable<BigInt> partialDeciphers0 = partialDeciphers
.Where(partialDecipher => partialDecipher.GroupIndex == 1)
.Select(partialDecipher => partialDecipher.Value);
int v0 = sum.Decrypt(partialDeciphers0, parameters);
IEnumerable<BigInt> partialDeciphers1 = partialDeciphers
.Where(partialDecipher => partialDecipher.GroupIndex == 1)
.Select(partialDecipher => partialDecipher.Value);
int v1 = sum.Decrypt(partialDeciphers1, parameters);
IEnumerable<BigInt> partialDeciphers2 = partialDeciphers
.Where(partialDecipher => partialDecipher.GroupIndex == 1)
.Select(partialDecipher => partialDecipher.Value);
int v2 = sum.Decrypt(partialDeciphers2, parameters);
IEnumerable<BigInt> partialDeciphers3 = partialDeciphers
.Where(partialDecipher => partialDecipher.GroupIndex == 1)
.Select(partialDecipher => partialDecipher.Value);
int v3 = sum.Decrypt(partialDeciphers3, parameters);
IEnumerable<BigInt> partialDeciphers4 = partialDeciphers
.Where(partialDecipher => partialDecipher.GroupIndex == 1)
.Select(partialDecipher => partialDecipher.Value);
int v4 = sum.Decrypt(partialDeciphers4, parameters);
if (v0 == v1 &&
v0 == v2 &&
v0 == v3 &&
v0 == v4)
{
throw new Exception("Everything ok.");
}
else
{
throw new Exception("Bad vote.");
}
}
}
