Some OpenSocial containers use `xoauth_security_token` for signing requests, instead of `oauth_token` and `oauth_token_secret`.

Is XOauth an alternative to OAuth?(\*) Who is behind XOauth and where is the official spec?

Casual Googling only lead me to [xoauth.py](http://google-mail-xoauth-tools.googlecode.com/svn/trunk/python/xoauth.py) from google-mail-xoauth-tools project which just states it's a "utilities for XOAUTH authentication".

(\*)Aside: it mustn't be, because the container uses other oauth\_xxx parameters alongside the xoauth\_xxx ones.