/**
* Helper function to create IdemixSigningIdentity from a file generated by idemixgen go tool
*
* @param mspId
* @return IdemixSigningIdentity object
* @throws IOException
* @throws InvalidProtocolBufferException
*/
private IdemixSigningIdentity CreateIdemixSigningIdentity(string mspId)
{
IdemixMSPSignerConfig signerConfig;
signerConfig = ReadIdemixMSPConfig(Path.Combine(TEST_PATH, mspId, USER_PATH).Locate(), SIGNER_CONFIG);
Assert.IsNotNull(signerConfig);
IssuerPublicKey ipkProto = ReadIdemixIssuerPublicKey(Path.Combine(TEST_PATH, mspId, VERIFIER_PATH).Locate(), IPK_CONFIG);
IdemixIssuerPublicKey ipkt = new IdemixIssuerPublicKey(ipkProto);
Assert.IsTrue(ipkt.Check());
KeyPair revPk = ReadIdemixRevocationPublicKey(Path.Combine(TEST_PATH, mspId, VERIFIER_PATH).Locate(), REVOCATION_PUBLIC_KEY);
BIG skt = BIG.FromBytes(signerConfig.Sk.ToByteArray());
Credential credProto = Credential.Parser.ParseFrom(signerConfig.Cred);
Assert.IsNotNull(credProto);
IdemixCredential credt = new IdemixCredential(credProto);
CredentialRevocationInformation crit = CredentialRevocationInformation.Parser.ParseFrom(signerConfig.CredentialRevocationInformation);
return(new IdemixSigningIdentity(ipkt, revPk, mspId, skt, credt, crit, signerConfig.OrganizationalUnitIdentifier, (IdemixRoles)signerConfig.Role));
}
public IdemixEnrollment(IdemixIssuerPublicKey ipk, KeyPair revocationPk, string mspId, BIG sk, IdemixCredential cred, CredentialRevocationInformation cri, string ou, IdemixRoles roleMask)
{
Ipk = ipk;
RevocationPk = revocationPk;
MspId = mspId;
Sk = sk;
Cred = cred;
Cri = cri;
Ou = ou;
RoleMask = roleMask;
}
public IUser GetUser(string id)
{
IdemixMSPSignerConfig signerConfig = ReadIdemixMSPConfig(Path.Combine(mspId, USER_PATH + id));
KeyPair revocationPk = ReadIdemixRevocationPublicKey(mspId);
BIG sk = BIG.FromBytes(signerConfig.Sk.ToByteArray());
IdemixCredential cred = new IdemixCredential(Credential.Parser.ParseFrom(signerConfig.Cred));
CredentialRevocationInformation cri = CredentialRevocationInformation.Parser.ParseFrom(signerConfig.CredentialRevocationInformation);
IdemixEnrollment enrollment = new IdemixEnrollment(ipk, revocationPk, mspId, sk, cred, cri, signerConfig.OrganizationalUnitIdentifier, (IdemixRoles)signerConfig.Role);
return(new IdemixUser(id, mspId, enrollment));
}
/**
* Verifies that the revocation PK for a certain epoch is valid,
* by checking that it was signed with the long term revocation key
*
* @param pk Public Key
* @param epochPK Epoch PK
* @param epochPkSig Epoch PK Signature
* @param epoch Epoch
* @param alg Revocation algorithm
* @return True if valid
*/
public static bool VerifyEpochPK(KeyPair pk, ECP2 epochPK, byte[] epochPkSig, long epoch, RevocationAlgorithm alg)
{
CredentialRevocationInformation cr = new CredentialRevocationInformation();
cr.RevocationAlg = (int)alg;
cr.EpochPk = epochPK;
cr.Epoch = epoch;
byte[] bytesTosign = cr.ToByteArray();
try
{
return(pk.Verify(bytesTosign, epochPkSig, "SHA256withECDSA"));
}
catch (Exception e)
{
throw new CryptoException("Error during the EpochPK verification", e);
}
}
/**
* 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");
}
/**
* Create a new IdemixSignature by proving knowledge of a credential
*
* @param c the credential used to create an idemix signature
* @param sk the signer's secret key
* @param pseudonym a pseudonym of the signer
* @param ipk the issuer public key
* @param disclosure a bool-array that steers the disclosure of attributes
* @param msg the message to be signed
* @param rhIndex the index of the attribute that represents the revocation handle
* @param cri the credential revocation information that allows the signer to prove non-revocation
*/
public IdemixSignature(IdemixCredential c, BIG sk, IdemixPseudonym pseudonym, IdemixIssuerPublicKey ipk, bool[] disclosure, byte[] msg, int rhIndex, CredentialRevocationInformation cri)
{
if (c == null || sk == null || pseudonym == null || pseudonym.Nym == null || pseudonym.RandNym == null || ipk == null || disclosure == null || msg == null || cri == null)
{
throw new ArgumentException("Cannot construct idemix signature from null input");
}
if (disclosure.Length != c.Attrs.Length)
{
throw new ArgumentException("Disclosure length must be the same as the number of attributes");
}
if (cri.RevocationAlg >= Enum.GetValues(typeof(RevocationAlgorithm)).Length)
{
throw new ArgumentException("CRI specifies unknown revocation algorithm");
}
if (cri.RevocationAlg != (int)RevocationAlgorithm.ALG_NO_REVOCATION && disclosure[rhIndex])
{
throw new ArgumentException("Attribute " + rhIndex + " is disclosed but also used a revocation handle attribute, which should remain hidden");
}
RevocationAlgorithm revocationAlgorithm = (RevocationAlgorithm)cri.RevocationAlg;
int[] hiddenIndices = HiddenIndices(disclosure);
RAND rng = IdemixUtils.GetRand();
// Start signature
BIG r1 = rng.RandModOrder();
BIG r2 = rng.RandModOrder();
BIG r3 = new BIG(r1);
r3.InvModp(IdemixUtils.GROUP_ORDER);
nonce = rng.RandModOrder();
aPrime = PAIR.G1Mul(c.A, r1);
aBar = PAIR.G1Mul(c.B, r1);
aBar.Sub(PAIR.G1Mul(aPrime, c.E));
bPrime = PAIR.G1Mul(c.B, r1);
bPrime.Sub(PAIR.G1Mul(ipk.HRand, r2));
BIG sPrime = new BIG(c.S);
sPrime.Add(BIG.ModNeg(BIG.ModMul(r2, r3, IdemixUtils.GROUP_ORDER), IdemixUtils.GROUP_ORDER));
sPrime.Mod(IdemixUtils.GROUP_ORDER);
//Construct Zero Knowledge Proof
BIG rsk = rng.RandModOrder();
BIG re = rng.RandModOrder();
BIG rR2 = rng.RandModOrder();
BIG rR3 = rng.RandModOrder();
BIG rSPrime = rng.RandModOrder();
BIG rRNym = rng.RandModOrder();
BIG[] rAttrs = new BIG[hiddenIndices.Length];
for (int i = 0; i < hiddenIndices.Length; i++)
{
rAttrs[i] = rng.RandModOrder();
}
// Compute non-revoked proof
INonRevocationProver prover = NonRevocationProver.GetNonRevocationProver(revocationAlgorithm);
int hiddenRHIndex = Array.IndexOf(hiddenIndices, rhIndex);
if (hiddenRHIndex < 0)
{
// rhIndex is not present, set to last index position
hiddenRHIndex = hiddenIndices.Length;
}
byte[] nonRevokedProofHashData = prover.GetFSContribution(BIG.FromBytes(c.Attrs[rhIndex]), rAttrs[hiddenRHIndex], cri);
if (nonRevokedProofHashData == null)
{
throw new Exception("Failed to compute non-revoked proof");
}
ECP t1 = aPrime.Mul2(re, ipk.HRand, rR2);
ECP t2 = PAIR.G1Mul(ipk.HRand, rSPrime);
t2.Add(bPrime.Mul2(rR3, ipk.Hsk, rsk));
for (int i = 0; i < hiddenIndices.Length / 2; i++)
{
t2.Add(ipk.HAttrs[hiddenIndices[2 * i]].Mul2(rAttrs[2 * i], ipk.HAttrs[hiddenIndices[2 * i + 1]], rAttrs[2 * i + 1]));
}
if (hiddenIndices.Length % 2 != 0)
{
t2.Add(PAIR.G1Mul(ipk.HAttrs[hiddenIndices[hiddenIndices.Length - 1]], rAttrs[hiddenIndices.Length - 1]));
}
ECP t3 = ipk.Hsk.Mul2(rsk, ipk.HRand, rRNym);
// create proofData such that it can contain the sign label, 7 elements in G1 (each of size 2*FIELD_BYTES+1),
// the ipk hash, the disclosure array, and the message
byte[] proofData = new byte[0];
proofData = proofData.Append(SIGN_LABEL.ToBytes());
proofData = proofData.Append(t1.ToBytes());
proofData = proofData.Append(t2.ToBytes());
proofData = proofData.Append(t3.ToBytes());
proofData = proofData.Append(aPrime.ToBytes());
proofData = proofData.Append(aBar.ToBytes());
proofData = proofData.Append(bPrime.ToBytes());
proofData = proofData.Append(pseudonym.Nym.ToBytes());
proofData = proofData.Append(ipk.Hash);
proofData = proofData.Append(disclosure);
proofData = proofData.Append(msg);
BIG cvalue = proofData.HashModOrder();
byte[] finalProofData = new byte[0];
finalProofData = finalProofData.Append(cvalue.ToBytes());
finalProofData = finalProofData.Append(nonce.ToBytes());
proofC = finalProofData.HashModOrder();
proofSSk = rsk.ModAdd(BIG.ModMul(proofC, sk, IdemixUtils.GROUP_ORDER), IdemixUtils.GROUP_ORDER);
proofSE = re.ModSub(BIG.ModMul(proofC, c.E, IdemixUtils.GROUP_ORDER), IdemixUtils.GROUP_ORDER);
proofSR2 = rR2.ModAdd(BIG.ModMul(proofC, r2, IdemixUtils.GROUP_ORDER), IdemixUtils.GROUP_ORDER);
proofSR3 = rR3.ModSub(BIG.ModMul(proofC, r3, IdemixUtils.GROUP_ORDER), IdemixUtils.GROUP_ORDER);
proofSSPrime = rSPrime.ModAdd(BIG.ModMul(proofC, sPrime, IdemixUtils.GROUP_ORDER), IdemixUtils.GROUP_ORDER);
proofSRNym = rRNym.ModAdd(BIG.ModMul(proofC, pseudonym.RandNym, IdemixUtils.GROUP_ORDER), IdemixUtils.GROUP_ORDER);
nym = new ECP();
nym.Copy(pseudonym.Nym);
proofSAttrs = new BIG[hiddenIndices.Length];
for (int i = 0; i < hiddenIndices.Length; i++)
{
proofSAttrs[i] = new BIG(rAttrs[i]);
proofSAttrs[i].Add(BIG.ModMul(proofC, BIG.FromBytes(c.Attrs[hiddenIndices[i]]), IdemixUtils.GROUP_ORDER));
proofSAttrs[i].Mod(IdemixUtils.GROUP_ORDER);
}
// include non-revocation proof in signature
revocationPk = cri.EpochPk;
revocationPKSig = cri.EpochPkSig.ToByteArray();
epoch = cri.Epoch;
nonRevocationProof = prover.GetNonRevocationProof(proofC);
}
public byte[] GetFSContribution(BIG rh, BIG rRh, CredentialRevocationInformation cri)
{
return(empty);
}
private void Test()
{
RAND rng = IdemixUtils.GetRand();
// WeakBB test
// Random message to sign
BIG wbbMessage = rng.RandModOrder();
// Sign the message with keypair secret key
ECP wbbSignature = WeakBB.WeakBBSign(setup.wbbKeyPair.Sk, wbbMessage);
// Check the signature with valid PK and valid message
Assert.IsTrue(WeakBB.weakBBVerify(setup.wbbKeyPair.Pk, wbbSignature, wbbMessage));
// Try to check a random message
Assert.IsFalse(WeakBB.weakBBVerify(setup.wbbKeyPair.Pk, wbbSignature, rng.RandModOrder()));
// user completes the idemixCredential and checks validity
Assert.IsTrue(setup.idemixCredential.Verify(setup.sk, setup.key.Ipk));
// Test serialization of IdemixidemixCredential
Assert.IsTrue(new IdemixCredential(setup.idemixCredential.ToProto()).Verify(setup.sk, setup.key.Ipk));
// Create CRI that contains no revocation mechanism
int epoch = 0;
BIG[] rhIndex = { new BIG(0) };
CredentialRevocationInformation cri = RevocationAuthority.CreateCRI(setup.revocationKeyPair, rhIndex, epoch, RevocationAlgorithm.ALG_NO_REVOCATION);
// Create a new unlinkable pseudonym
IdemixPseudonym pseudonym = new IdemixPseudonym(setup.sk, setup.key.Ipk); //tcert
// Test signing no disclosure
bool[] disclosure = { false, false, false, false, false };
byte[] msg = { 1, 2, 3, 4, 5 };
IdemixSignature signature = new IdemixSignature(setup.idemixCredential, setup.sk, pseudonym, setup.key.Ipk, disclosure, msg, 0, cri);
Assert.IsNotNull(signature);
// Test bad disclosure: Disclosure > number of attributes || Disclosure < number of attributes
bool[] badDisclosure = { false, true };
bool[] badDisclosure2 = { true, true, true, true, true, true, true };
try
{
new IdemixSignature(setup.idemixCredential, setup.sk, pseudonym, setup.key.Ipk, badDisclosure, msg, 0, cri);
new IdemixSignature(setup.idemixCredential, setup.sk, pseudonym, setup.key.Ipk, badDisclosure2, msg, 0, cri);
Assert.Fail("Expected an ArgumentException");
}
catch (ArgumentException)
{
//ignored
/* Do nothing, the expected behaviour is to catch this exception.*/
}
// check that the signature is valid
Assert.IsTrue(signature.Verify(disclosure, setup.key.Ipk, msg, setup.attrs, 0, setup.revocationKeyPair, epoch));
// Test serialization of IdemixSignature
Assert.IsTrue(new IdemixSignature(signature.ToProto()).Verify(disclosure, setup.key.Ipk, msg, setup.attrs, 0, setup.revocationKeyPair, epoch));
// Test signing selective disclosure
bool[] disclosure2 = { false, true, true, true, false };
signature = new IdemixSignature(setup.idemixCredential, setup.sk, pseudonym, setup.key.Ipk, disclosure2, msg, 0, cri);
Assert.IsNotNull(signature);
// check that the signature is valid
Assert.IsTrue(signature.Verify(disclosure2, setup.key.Ipk, msg, setup.attrs, 0, setup.revocationKeyPair, epoch));
// Test signature verification with different disclosure
Assert.IsFalse(signature.Verify(disclosure, setup.key.Ipk, msg, setup.attrs, 0, setup.revocationKeyPair, epoch));
// test signature verification with different issuer public key
Assert.IsFalse(signature.Verify(disclosure2, new IdemixIssuerKey(new [] { "Attr1, Attr2, Attr3, Attr4, Attr5" }).Ipk, msg, setup.attrs, 0, setup.revocationKeyPair, epoch));
// test signature verification with different message
byte[] msg2 = { 1, 1, 1 };
Assert.IsFalse(signature.Verify(disclosure2, setup.key.Ipk, msg2, setup.attrs, 0, setup.revocationKeyPair, epoch));
// Sign a message with respect to a pseudonym
IdemixPseudonymSignature nymsig = new IdemixPseudonymSignature(setup.sk, pseudonym, setup.key.Ipk, msg);
// check that the pseudonym signature is valid
Assert.IsTrue(nymsig.Verify(pseudonym.Nym, setup.key.Ipk, msg));
// Test serialization of IdemixPseudonymSignature
Assert.IsTrue(new IdemixPseudonymSignature(nymsig.ToProto()).Verify(pseudonym.Nym, setup.key.Ipk, msg));
}
/**
* Create new Idemix Signing Identity with a fresh pseudonym
*
* @param ipk issuer public key
* @param revocationPk the issuer's long term revocation public key
* @param mspId MSP identifier
* @param sk user's secret
* @param cred idemix credential
* @param cri the credential revocation information
* @param ou is OU attribute
* @param role is role attribute
* @throws CryptoException
* @throws InvalidArgumentException
*/
public IdemixSigningIdentity(IdemixIssuerPublicKey ipk, KeyPair revocationPk, string mspId, BIG sk, IdemixCredential cred, CredentialRevocationInformation cri, string ou, IdemixRoles role)
{
// input checks
if (ipk == null)
{
throw new ArgumentException("Issuer Public Key (IPK) must not be null");
}
if (revocationPk == null)
{
throw new ArgumentException("Revocation PK must not be null");
}
if (mspId == null)
{
throw new ArgumentException("MSP ID must not be null");
}
if (string.IsNullOrEmpty(mspId))
{
throw new ArgumentException("MSP ID must not be empty");
}
if (ou == null)
{
throw new ArgumentException("OU must not be null");
}
if (string.IsNullOrEmpty(ou))
{
throw new ArgumentException("OU must not be empty");
}
if (sk == null)
{
throw new ArgumentException("SK must not be null");
}
if (cred == null)
{
throw new ArgumentException("Credential must not be null");
}
if (cri == null)
{
throw new ArgumentException("Credential revocation information must not be null");
}
logger.Trace($"Verifying public key with hash: [{BitConverter.ToString(ipk.Hash).Replace("-", "")}] \nAttributes: [{string.Join(",", ipk.AttributeNames)}]");
if (!ipk.Check())
{
CryptoException e = new CryptoException("Issuer public key is not valid");
logger.Error("", e);
throw e;
}
this.ipk = ipk;
this.sk = sk;
this.cri = cri;
logger.Trace("Verifying the credential");
// cryptographically verify credential
// (check if the issuer's signature is valid)
if (!cred.Verify(sk, ipk))
{
CryptoException e = new CryptoException("Credential is not cryptographically valid");
logger.Error("", e);
throw e;
}
logger.Trace("Checking attributes");
// attribute checks
// 4 attributes are expected:
// - organization unit (disclosed)
// - role: admin or member (disclosed)
// - enrollment id (hidden, for future auditing feature and authorization with CA)
// - revocation handle (hidden, for future revocation support)
if (cred.Attrs.Length != 4)
{
throw new CryptoException($"Error: There are {cred.Attrs.Length} attributes and the expected are 4");
}
byte[] ouBytes = cred.Attrs[0];
byte[] roleBytes = cred.Attrs[1];
byte[] eIdBytes = cred.Attrs[2];
byte[] rHBytes = cred.Attrs[3];
BIG[] attributes = new BIG[4];
attributes[0] = BIG.FromBytes(ouBytes);
attributes[1] = BIG.FromBytes(roleBytes);
attributes[2] = BIG.FromBytes(eIdBytes);
attributes[3] = BIG.FromBytes(rHBytes);
// check that the OU string matches the credential's attribute value
if (!ou.ToBytes().HashModOrder().ToBytes().SequenceEqual(ouBytes))
{
throw new ArgumentException("the OU string does not match the credential");
}
// check that the role matches the credential's attribute value
if (!new BIG((int)role).ToBytes().SequenceEqual(roleBytes))
{
throw new ArgumentException("the role does not match the credential");
}
logger.Trace("Generating fresh pseudonym and proof");
// generate a fresh pseudonym
Pseudonym = new IdemixPseudonym(this.sk, this.ipk);
// generate a fresh proof of possession of a credential
// with respect to a freshly generated pseudonym
Proof = new IdemixSignature(cred, this.sk, Pseudonym, this.ipk, disclosedFlags, msgEmpty, rhIndex, cri);
logger.Trace("Verifying the proof");
// verify the proof
if (!Proof.Verify(disclosedFlags, this.ipk, msgEmpty, attributes, rhIndex, revocationPk, (int)cri.Epoch))
{
throw new CryptoException("Generated proof of identity is not valid");
}
logger.Trace("Generating the Identity Object");
// generate a fresh identity with new pseudonym
idemixIdentity = new IdemixIdentity(mspId, this.ipk, Pseudonym.Nym, ou, role, Proof);
logger.Trace(idemixIdentity.ToString());
}
public static void Setup(TestContext context)
{
// Parse crypto material from files
IdemixMSPSignerConfig signerConfig = null;
try
{
signerConfig = ReadIdemixMSPConfig(Path.Combine(TEST_PATH, MSP1OU1, USER_PATH).Locate(), SIGNER_CONFIG);
}
catch (System.Exception e)
{
Assert.Fail("Unexpected exception while reading signerconfig: " + e.Message);
}
Assert.IsNotNull(signerConfig);
try
{
revocationPk = ReadIdemixRevocationPublicKey(Path.Combine(TEST_PATH, MSP1OU1, VERIFIER_PATH).Locate(), REVOCATION_PUBLIC_KEY);
}
catch (System.Exception e)
{
Assert.Fail("Unexpected exception while reading revocation public key: " + e.Message);
}
Assert.IsNotNull(revocationPk);
IssuerPublicKey ipkProto = null;
try
{
ipkProto = ReadIdemixIssuerPublicKey(Path.Combine(TEST_PATH, MSP1OU1, VERIFIER_PATH).Locate(), IPK_CONFIG);
}
catch (IOException e1)
{
Assert.Fail("Unexpected exception while reading revocation public key" + e1.Message);
}
ipk = new IdemixIssuerPublicKey(ipkProto);
Assert.IsTrue(ipk.Check());
sk = BIG.FromBytes(signerConfig.Sk.ToByteArray());
Credential credProto = null;
try
{
credProto = Credential.Parser.ParseFrom(signerConfig.Cred);
}
catch (InvalidProtocolBufferException)
{
Assert.Fail("Could not parse a credential");
}
Assert.IsNotNull(credProto);
cred = new IdemixCredential(credProto);
try
{
cri = CredentialRevocationInformation.Parser.ParseFrom(signerConfig.CredentialRevocationInformation);
}
catch (InvalidProtocolBufferException e)
{
Assert.Fail("failed to extract cri from signer config: " + e.Message);
}
Assert.IsNotNull(cri);
try
{
signingIdentity = new IdemixSigningIdentity(ipk, revocationPk, MSP1OU1, sk, cred, cri, OU1, IdemixRoles.MEMBER);
}
catch (System.Exception e) when(e is CryptoException || e is ArgumentException)
{
Assert.Fail("Could not create Idemix Signing Identity" + e.Message);
}
Assert.IsNotNull(signingIdentity);
nym = signingIdentity.Pseudonym;
nymPublic = nym.Nym;
proof = signingIdentity.Proof;
}