private byte[] Decrypt(SignalServiceEnvelope envelope, byte[] ciphertext)
{
SignalProtocolAddress sourceAddress = new SignalProtocolAddress(envelope.GetSource(), (uint)envelope.GetSourceDevice());
SessionCipher sessionCipher = new SessionCipher(SignalProtocolStore, sourceAddress);
byte[] paddedMessage;
if (envelope.IsPreKeySignalMessage())
{
paddedMessage = sessionCipher.decrypt(new PreKeySignalMessage(ciphertext));
}
else if (envelope.IsSignalMessage())
{
paddedMessage = sessionCipher.decrypt(new SignalMessage(ciphertext));
}
else
{
throw new InvalidMessageException("Unknown type: " + envelope.GetEnvelopeType() + " from " + envelope.GetSource());
}
PushTransportDetails transportDetails = new PushTransportDetails(sessionCipher.getSessionVersion());
return(transportDetails.GetStrippedPaddingMessageBody(paddedMessage));
}
private Plaintext Decrypt(SignalServiceEnvelope envelope, byte[] ciphertext)
{
try
{
SignalProtocolAddress sourceAddress = new SignalProtocolAddress(envelope.GetSource(), (uint)envelope.GetSourceDevice());
SessionCipher sessionCipher = new SessionCipher(SignalProtocolStore, sourceAddress);
SealedSessionCipher sealedSessionCipher = new SealedSessionCipher(SignalProtocolStore, new SignalProtocolAddress(LocalAddress.E164number, 1));
byte[] paddedMessage;
Metadata metadata;
uint sessionVersion;
if (envelope.IsPreKeySignalMessage())
{
paddedMessage = sessionCipher.decrypt(new PreKeySignalMessage(ciphertext));
metadata = new Metadata(envelope.GetSource(), envelope.GetSourceDevice(), envelope.GetTimestamp(), false);
sessionVersion = sessionCipher.getSessionVersion();
}
else if (envelope.IsSignalMessage())
{
paddedMessage = sessionCipher.decrypt(new SignalMessage(ciphertext));
metadata = new Metadata(envelope.GetSource(), envelope.GetSourceDevice(), envelope.GetTimestamp(), false);
sessionVersion = sessionCipher.getSessionVersion();
}
else if (envelope.IsUnidentifiedSender())
{
var results = sealedSessionCipher.Decrypt(CertificateValidator, ciphertext, (long)envelope.Envelope.ServerTimestamp);
paddedMessage = results.Item2;
metadata = new Metadata(results.Item1.Name, (int)results.Item1.DeviceId, (long)envelope.Envelope.Timestamp, true);
sessionVersion = (uint)sealedSessionCipher.GetSessionVersion(new SignalProtocolAddress(metadata.Sender, (uint)metadata.SenderDevice));
}
else
{
throw new InvalidMessageException("Unknown type: " + envelope.GetEnvelopeType() + " from " + envelope.GetSource());
}
PushTransportDetails transportDetails = new PushTransportDetails(sessionVersion);
byte[] data = transportDetails.GetStrippedPaddingMessageBody(paddedMessage);
return(new Plaintext(metadata, data));
}
catch (DuplicateMessageException e)
{
throw new ProtocolDuplicateMessageException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
catch (LegacyMessageException e)
{
throw new ProtocolLegacyMessageException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
catch (InvalidMessageException e)
{
throw new ProtocolInvalidMessageException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
catch (InvalidKeyIdException e)
{
throw new ProtocolInvalidKeyIdException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
catch (InvalidKeyException e)
{
throw new ProtocolInvalidKeyException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
catch (libsignal.exceptions.UntrustedIdentityException e)
{
throw new ProtocolUntrustedIdentityException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
catch (InvalidVersionException e)
{
throw new ProtocolInvalidVersionException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
catch (NoSessionException e)
{
throw new ProtocolNoSessionException(e, envelope.GetSource(), envelope.GetSourceDevice());
}
}
