private void ProcessSignatureMessage(OTRMessage otr_message)
{
DebugPrint("Received Signature Message");
_otr_event_args = new OTREventArgs();
if (_authentication_state != OTR_AUTH_STATE.AUTH_STATE_AWAITING_SIG)
{
OTRError("ProcessSignatureMessage: OTR Engine is not in the AUTH_STATE_AWAITING_SIG state",
"ProcessSignatureMessage: OTR Engine is not in the AUTH_STATE_AWAITING_SIG state",
null);
return;
}
if (otr_message.GetEncodedEncryptedSignature() == null || otr_message.GetEncodedEncryptedSignature().Length < 1)
{
OTRError("ProcessSignatureMessage: The encoded encrypted signature byte array cannot be null/empty", null,
"OTR Failed. Unexpected error");
return;
}
if (otr_message.GetMacDSignature() == null || otr_message.GetMacDSignature().Length < 1)
{
OTRError("ProcessSignatureMessage: The MAC'd signature byte array cannot be null/empty", null,
"OTR Failed. Unexpected error");
return;
}
_otr_event_args.SetOTREvent(OTR_EVENT.ERROR);
byte[] dsa_public_key_byte_array_encoded = null;
bool _is_sig_verified = SignatureManager.IsSignatureVerified(_ake_keys, _otr_session_object.GetMyRecentDHKeyPair(), _otr_session_object.GetBuddyRecentPublicKeyMpi(),
otr_message.GetEncodedEncryptedSignature(), otr_message.GetMacDSignature(), false, ref _temp_int_32_val, ref dsa_public_key_byte_array_encoded);
if (_otr_session_object.IsComputeBuddyFingerPrint(dsa_public_key_byte_array_encoded) == false)
{
OTRError("ProcessSignatureMessage:" + _my_buddy_unique_id + "'s DSA public key fingerprint computation failed",
"ProcessSignatureMessage:" + _my_buddy_unique_id + "'s DSA public key fingerprint computation failed",
null);
_authentication_state = OTR_AUTH_STATE.AUTH_STATE_NONE;
return;
}
if (_is_sig_verified != true)
{
OTRError("ProcessSignatureMessage:" + _my_buddy_unique_id + "'s signature verification failed",
"ProcessSignatureMessage:" + _my_buddy_unique_id + "'s signature verification failed",
null);
_authentication_state = OTR_AUTH_STATE.AUTH_STATE_NONE;
return;
}
/* Inform client of OTR readiness */
_otr_session_object.SetFirstBuddyPublicKeyID(_temp_int_32_val);
_authentication_state = OTR_AUTH_STATE.AUTH_STATE_NONE;
_message_state = OTR_MESSAGE_STATE.MSG_STATE_ENCRYPTED;
_otr_event_args.SetOTREvent(OTR_EVENT.READY);
_otr_event_args.SetMessage(_my_buddy_unique_id + "'s signature verification successful");
DoOTREvent(_otr_event_args);
}
private void CloseOTRSession(string session_closed_message)
{
DebugPrint("Ending OTR session");
_otr_event_args = new OTREventArgs();
_otr_event_args.SetMessage(session_closed_message);
_otr_event_args.SetOTREvent(OTR_EVENT.CLOSED);
DoOTREvent(_otr_event_args);
_message_state = OTR_MESSAGE_STATE.MSG_STATE_PLAINTEXT;
_message_manager = null;
_ake_keys_manager = null;
_dsa_signer = null;
_signature_manager = null;
_smp_manager = null;
_ake_keys = null;
_my_unique_id = string.Empty;
_my_buddy_unique_id = string.Empty;
_otr_fragment_object = null;
EndSMPSession();
}
private void ProcessRevealSigMessage(OTRMessage otr_message)
{
DebugPrint("Received Reveal Signature Message");
_otr_event_args = new OTREventArgs();
if (_authentication_state != OTR_AUTH_STATE.AUTH_STATE_AWAITING_REVEAL_SIG)
{
OTRError("ProcessRevealSigMessage: OTR Engine is not in the AUTH_STATE_AWAITING_REVEAL_SIG state",
"ProcessRevealSigMessage: OTR Engine is not in the AUTH_STATE_AWAITING_REVEAL_SIG state",
null);
return;
}
if (otr_message.GetRevealedKey() == null || otr_message.GetRevealedKey().Length < 1)
{
OTRError("ProcessRevealSigMessage: The AES revealed key byte array cannot be null/empty", null,
"OTR Failed. Unexpected error");
return;
}
if (otr_message.GetEncodedEncryptedSignature() == null || otr_message.GetEncodedEncryptedSignature().Length < 1)
{
OTRError("ProcessRevealSigMessage: The encoded encrypted signature byte array cannot be null/empty", null,
"OTR Failed. Unexpected error");
return;
}
if (otr_message.GetMacDSignature() == null || otr_message.GetMacDSignature().Length < 1)
{
OTRError("ProcessRevealSigMessage: The MAC'd signature byte array cannot be null/empty", null,
"OTR Failed. Unexpected error");
return;
}
_otr_event_args.SetOTREvent(OTR_EVENT.ERROR);
if (_dh_commit_message == null || _dh_commit_message.GetEncryptedGxMpi() == null || _dh_commit_message.GetEncryptedGxMpi().Length < 1)
{
OTRError("ProcessRevealSigMessage: The MPI encoded encrypted public key (g^x mpi) should not be null/empty",
"ProcessRevealSigMessage: The MPI encoded encrypted public key (g^x mpi) should not be null/empty",
"OTR Failed. Unexpected error");
return;
}
if (_otr_session_object.IsSetMyBuddyFirstPublicKey(otr_message.GetRevealedKey(), _dh_commit_message.GetEncryptedGxMpi(),
_dh_commit_message.GetHashedGxMpi()) == false)
{
OTRError("ProcessRevealSigMessage: The MPI encoded decrypted public key (g^x mpi) should not be null/empty",
"ProcessRevealSigMessage: The MPI encoded decrypted public key (g^x mpi) should not be null/empty",
"OTR Failed. Unexpected error");
return;
}
_ake_keys = _ake_keys_manager.ComputeKeys(_otr_session_object.GetMyRecentDHKeyPair(), _otr_session_object.GetBuddyRecentPublicKey());
byte[] dsa_public_key_byte_array_encoded = null;
bool _is_sig_verified = SignatureManager.IsSignatureVerified(_ake_keys, _otr_session_object.GetMyRecentDHKeyPair(), _otr_session_object.GetBuddyRecentPublicKeyMpi(),
otr_message.GetEncodedEncryptedSignature(), otr_message.GetMacDSignature(), true, ref _temp_int_32_val, ref dsa_public_key_byte_array_encoded);
if (_otr_session_object.IsComputeBuddyFingerPrint(dsa_public_key_byte_array_encoded) == false)
{
OTRError("ProcessRevealSigMessage:" + _my_buddy_unique_id + "'s DSA public key fingerprint computation failed",
"ProcessRevealSigMessage:" + _my_buddy_unique_id + "'s DSA public key fingerprint computation failed",
null);
_authentication_state = OTR_AUTH_STATE.AUTH_STATE_NONE;
return;
}
if (_is_sig_verified != true)
{
OTRError("ProcessRevealSigMessage:" + _my_buddy_unique_id + "'s signature verification failed",
"ProcessRevealSigMessage:" + _my_buddy_unique_id + "'s signature verification failed",
"OTR Failed. Unexpected error");
_authentication_state = OTR_AUTH_STATE.AUTH_STATE_NONE;
return;
}
_signature_manager.ComputeSignature(_ake_keys, _otr_session_object.GetMyRecentDHKeyPair().GetPublicKeyMpiBytes(), _otr_session_object.GetMyRecentDHKeyPair().GetKeyIDBytes(),
_otr_session_object.GetBuddyRecentPublicKeyMpi(), _otr_session_object.GetCounter(), false);
//Send signature message
byte[] _dh_signature_byte_array = _message_manager.FormatSignature(_signature_manager.GetSignatureDataBytes());
DebugPrint("Sending Signature Message");
SendOTRMessage(_dh_signature_byte_array);
/* Inform client of OTR readiness */
_otr_session_object.SetFirstBuddyPublicKeyID(_temp_int_32_val);
_authentication_state = OTR_AUTH_STATE.AUTH_STATE_NONE;
_message_state = OTR_MESSAGE_STATE.MSG_STATE_ENCRYPTED;
_otr_event_args.SetOTREvent(OTR_EVENT.READY);
_otr_event_args.SetMessage(_my_buddy_unique_id + "'s signature verification successful");
DoOTREvent(_otr_event_args);
}
