public AKEKeys ComputeKeys(DHKeyPair my_key_pair, BigInteger public_key)
{
if (Utility.IsValidPublicKey(public_key) == false)
throw new ArgumentException("AKEKeysManager:Public key is invalid");
if (my_key_pair == null)
throw new ArgumentException("AKEKeysManager: My Key Pair cannot be null");
if (my_key_pair.GetPrivateKey() < 1)
throw new ArgumentException("AKEKeysManager: Private key in my_key_pair value cannot be less than 0");
if (public_key < 1)
throw new ArgumentException("AKEKeysManager: Public key value cannot be less than 0");
_ake_keys = new AKEKeys();
_secret = Utility.ComputeSecret(my_key_pair, public_key, OTRConstants.RFC_3526_GENERATOR, OTRConstants.RFC_3526_PRIME_MODULO());
Utility.SetSecByteMpi(_secret, ref _sec_data_byte_array_mpi);
_ake_keys.SetSecData(_sec_data_byte_array_mpi);
ComputeSessionIDByte();
ComputeEncryptionKeysBytes();
ComputeMACKeysBytes();
return _ake_keys;
}
public DHKeyPair GenerateKeyPair()
{
key_serial++;
DHKeyPair _key_pair = new DHKeyPair(key_serial);
_key_pair.SetPrivateKey(Utility.GetRandBigInt(OTRConstants.DH_PRIVATE_KEY_MINIMUM_LENGTH_BITS));
_key_pair.SetPublicKey(BigInteger.ModPow(OTRConstants.RFC_3526_GENERATOR, _key_pair.GetPrivateKey(), OTRConstants.RFC_3526_PRIME_MODULO()));
return _key_pair;
}
public DataExchangeKeys ComputeKeys(DHKeyPair my_key_pair, BigInteger buddy_public_key)
{
if (Utility.IsValidPublicKey(buddy_public_key) == false)
throw new ArgumentException("DataExchangeKeysManager:Buddy public key is invalid");
if (my_key_pair == null)
throw new ArgumentException("DataExchangeKeysManager: My Key Pair cannot be null");
if (my_key_pair.GetPrivateKey() < 1)
throw new ArgumentException("DataExchangeKeysManager: Private key in my_key_pair value cannot be less than 0");
if (buddy_public_key < 1)
throw new ArgumentException("DataExchangeKeysManager: Buddy public key value cannot be less than 0");
if (my_key_pair.GetPublicKey() > buddy_public_key)
{
_end_type = OTR_END_TYPE.HIGH_END;
_send_byte = OTRConstants.HIGH_END_SEND_BYTE_VALUE;
_recv_byte = OTRConstants.HIGH_END_RECV_BYTE_VALUE;
}
else
{
_end_type = OTR_END_TYPE.LOW_END;
_send_byte = OTRConstants.LOW_END_SEND_BYTE_VALUE;
_recv_byte = OTRConstants.LOW_END_RECV_BYTE_VALUE;
}
_data_exchange_keys = new DataExchangeKeys();
_data_exchange_keys.SetEndType(_end_type);
_secret = Utility.ComputeSecret(my_key_pair, buddy_public_key, OTRConstants.RFC_3526_GENERATOR, OTRConstants.RFC_3526_PRIME_MODULO());
Utility.SetSecByteMpi(_secret, ref _sec_data_byte_array_mpi);
_data_exchange_keys.SetSecData(_sec_data_byte_array_mpi);
ComputeSendKeys();
ComputeRecvKeys();
ComputeAesExtraKey();
return _data_exchange_keys;
}
public static BigInteger ComputeSecret(DHKeyPair my_key_pair, BigInteger public_key, BigInteger generator, BigInteger prime_modulo)
{
if (my_key_pair == null)
throw new ArgumentException("ComputeSecret: My Key Pair cannot be null");
if (my_key_pair.GetPrivateKey() < 1)
throw new ArgumentException("ComputeSecret: Private key in my_key_pair value cannot be less than 0");
if (public_key < 1)
throw new ArgumentException("ComputeSecret: Public key value cannot be less than 0");
if (generator < 1)
throw new ArgumentException("ComputeSecret: Generator value cannot be less than 0");
if (prime_modulo < 1)
throw new ArgumentException("ComputeSecret: Prime Modulo value cannot be less than 0");
return BigInteger.ModPow(public_key, my_key_pair.GetPrivateKey(), prime_modulo);
}