node version

[jabolina]

I was using the whalesong installing it with pip, but this was creating a lot of communicatino between other js modules I have running in my project. So, I want to ask if its ok to you if I create a simple Whalesong version (monitor messages and chats in the beginning), using
you js script working with puppeteer?

I'll create a repo and publish in npm for others to use it, if it's ok.

[alfred82santa]

It's perfect. In fact it is one of my todo's #39

[jabolina]

Thanks! I'll add you as a collaborator, I'll be maintaining the repo, trying to keep up with the python version.

[jabolina]

Hi, I'm having some trouble with media messages decryption, this one. Can you say what was the logic?

Thanks!

[alfred82santa]

Well, I copied this code from tgalal/yowsup#1449 (comment)

But, more or less, this is the description:

L771: Download file
L776: Get media key from message. Fill with '=' in order to complete b64 string (multiple of 3)
L779: Compose crypto token (https://signal.org/docs/specifications/doubleratchet/#double-ratchet)
L785: Split crypto token in order to get IV and KEY (https://github.com/tgalal/python-axolotl/blob/master/axolotl/util/byteutil.py#L26)
L788: Remove last 10 bytes from file (I'm not sure why...)
L790: Create decryptor with IV and KEY
L792: Decrypt (AES-CBC: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation) file and finalize (Maybe finalize is about last 10 bytes...)

[alfred82santa]

May be, you could use https://github.com/signalapp/libsignal-protocol-javascript

[jabolina]

Thanks, that works perfectly!