[arbsn]

Is the encryption/decryption code in WhatsApp open-source? I haven't been able to find it. My assumption was that they conform to the Signal encryption protocol, which is openly specified, but that the code they use to do so is not open-source.

[moxie]

Yes, it is. It's linked directly from the paper (https://www.whatsapp.com/security/WhatsApp-Security-Whitepap...) that documents their use of the protocol.

It's the exact same code we use in Signal: https://github.com/whispersystems/libsignal-protocol-java