/**
* Depending on the selected revocation algorithm, the proof data length will be different.
* This method will give the proof length for any supported revocation algorithm.
*
* @param alg The revocation algorithm
* @return The proof data length for the given revocation algorithm
*/
public static int GetProofBytes(RevocationAlgorithm alg)
{
switch (alg)
{
case RevocationAlgorithm.ALG_NO_REVOCATION:
return(0);
default:
throw new ArgumentException("Unsupported RevocationAlgorithm: " + alg.ToString());
}
}
/**
* This method provides a non-revocation verifier depending on the Revocation algorithm
*
* @param algorithm Revocation mechanism to use
* @return NonRevocationVerifier or null if not allowed
*/
public static INonRevocationVerifier GetNonRevocationVerifier(RevocationAlgorithm algorithm)
{
switch (algorithm)
{
case RevocationAlgorithm.ALG_NO_REVOCATION:
return(new NopNonRevocationVerifier());
default:
// Revocation algorithm not supported
throw new Exception("Revocation algorithm " + algorithm.ToString() + " not supported");
}
}
/**
* Creates a Credential Revocation Information object
*
* @param key Private key
* @param unrevokedHandles Array of unrevoked revocation handles
* @param epoch The counter (representing a time window) in which this CRI is valid
* @param alg Revocation algorithm
* @return CredentialRevocationInformation object
*/
public static CredentialRevocationInformation CreateCRI(KeyPair key, BIG[] unrevokedHandles, int epoch, RevocationAlgorithm alg)
{
CredentialRevocationInformation cr = new CredentialRevocationInformation();
cr.RevocationAlg = (int)alg;
cr.Epoch = epoch;
// Create epoch key
WeakBB.KeyPair keyPair = WeakBB.WeakBBKeyGen();
if (alg == RevocationAlgorithm.ALG_NO_REVOCATION)
{
// Dummy PK in the proto
cr.EpochPk = IdemixUtils.GenG2.ToProto();
}
else
{
// Real PK only if we are going to use it
cr.EpochPk = keyPair.Pk.ToProto();
}
// Sign epoch + epoch key with the long term key
byte[] signed;
try
{
signed = key.Sign(cr.ToByteArray(), "SHA256withECDSA");
cr.EpochPkSig = ByteString.CopyFrom(signed);
}
catch (Exception e)
{
throw new CryptoException("Error processing the signature: ", e);
}
if (alg == RevocationAlgorithm.ALG_NO_REVOCATION)
{
// build and return the credential information object
return(cr);
}
// If alg not supported, return null
throw new ArgumentException("Algorithm " + alg.ToString() + " not supported");
}
