NodeJS - Crytography (S.S.E.)

Someone can help me to do the inverted operation of this? http://www.paranoiaworks.mobi/sse/file_encryption_specifications.html

I have encrypted a file on Android with an app that uses this specification (the algorithm was AES-256). I want to decrypt the file using node-js, the crypto module only is not sufficient, because there is not the necessary functions to derive the key like the app did. There is some library that I can use to do that?

PS: I need to decrypt it using node-js and not using their app for desktop because it's a very sensible file and I need to work with it only on memory.

Thanks in advance.

via Murillo Brandão