/**
* Endorse the proof
*
* @param aStampContext current context
* @param aProof proof
* @return endorsed proof
* @throws NoSuchAlgorithmException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws NoSuchPaddingException
* @throws InvalidKeyException
*/
private static byte[] endorseP(WitnessContext aStampContext, byte aProof[]) {
// Sign on the proof first
byte[] sig = {};
try {
sig = CryptoUtil.signDSA(aStampContext.getPriDSASelf(), aProof);
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (SignatureException e) {
e.printStackTrace();
}
// Include own ID in EP
byte[] wID = aStampContext.getPubDSASelf().getEncoded();
ArrayList<byte[]> array = new ArrayList<byte[]>();
array.add(wID);
array.add(aProof);
array.add(sig);
byte[] epContent = MessageUtil.compileMessages(array);
// Encrypt epContent with an AES key first
SecretKey aesKey = null;
byte[] epEncrypted = {};
byte[] keyEncrypted = {};
try {
aesKey = CryptoUtil.generateAESKey(128);
epEncrypted = CryptoUtil.encryptAES(aesKey, epContent);
keyEncrypted = CryptoUtil.encryptRSA(aStampContext.getPubRSACA(), aesKey.getEncoded());
} catch (NoSuchAlgorithmException e1) {
e1.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (IllegalBlockSizeException e) {
e.printStackTrace();
} catch (BadPaddingException e) {
e.printStackTrace();
}
ArrayList<byte[]> arrayOut = new ArrayList<byte[]>();
arrayOut.add(epEncrypted);
arrayOut.add(keyEncrypted);
return MessageUtil.compileMessages(arrayOut);
}
/**
* Create EP message body EP = r_w1|E^(K_ca)(ID_W|P|E^(K_W)(Hash(P)))
*
* @param aStampContext current context
* @return EP message body
*/
public static byte[] createEP(WitnessContext aStampContext) {
byte proof[] = createP(aStampContext);
byte eproof[] = endorseP(aStampContext, proof);
byte randomW[] = aStampContext.getEPRandomW().toByteArray();
ArrayList<byte[]> array = new ArrayList<byte[]>();
array.add(eproof);
array.add(randomW);
return MessageUtil.compileMessages(array);
}
/**
* Create Preq message body Preq = Comm(ID_P, r_P)|T|L_1
*
* @param aStampContext current context
* @param aLocLevel desired location level (0 usually)
* @return Preq message
*/
public static byte[] createPreq(ProverContext aStampContext) {
byte commID[] = aStampContext.getCommittedID();
byte time[] = ByteBuffer.allocate(8).putLong(ProverContext.getTime()).array();
/* TODO: check if aLocLevel is valid */
byte location[] = aStampContext.getLocation().toString().getBytes();
ArrayList<byte[]> array = new ArrayList<byte[]>();
array.add(commID);
array.add(time);
array.add(location);
return MessageUtil.compileMessages(array);
}
/**
* Create a proof P = Comm(ID_p, r_p)|C_k|C_e|STPR
*
* @param aStampContext current context
* @return proof
*/
private static byte[] createP(WitnessContext aStampContext) {
byte commID[] = aStampContext.getRemoteCommittedID();
byte z[] = aStampContext.getRemoteZ().toByteArray();
byte location[] = aStampContext.getRemoteLocation();
byte time[] = aStampContext.getRemoteTime();
byte stpr[] = createSTPR(aStampContext, location, time);
ArrayList<byte[]> array = new ArrayList<byte[]>();
array.add(commID);
array.add(z);
array.add(stpr);
return MessageUtil.compileMessages(array);
}
/**
* Create DB ready message body
*
* @return DB ready message
*/
public static byte[] createCeCk(ProverContext aStampContext) {
BigInteger e = aStampContext.getE();
BigInteger k = aStampContext.getK();
BigInteger p = aStampContext.getPubDSASelf().getParams().getP();
BigInteger g = aStampContext.getPubDSASelf().getParams().getG();
BigInteger h = aStampContext.getH();
BigInteger v = aStampContext.getV();
ArrayList<byte[]> ces = CryptoUtil.getBitCommitments(g, p, h, v, e);
ArrayList<byte[]> cks = CryptoUtil.getBitCommitments(g, p, h, v, k);
byte[] cesBytes = MessageUtil.createMessageFromArray(ces);
byte[] cksBytes = MessageUtil.createMessageFromArray(cks);
ArrayList<byte[]> array = new ArrayList<byte[]>();
array.add(cesBytes);
array.add(cksBytes);
return MessageUtil.compileMessages(array);
}
