salsa20.js

*
    * Salsa 20 
    * unified from http://code.ohloh.net/file?fid=v-0xBPS2xdNtbDPzjFZXCY89n0A&cid=vPv6IIgR6co
    * & Contribution to Cryptocat by Dmitry Chestnykh 21-01-2013
    * Snippet is analysed and tested against D.J.Bernsteins original C-Implementation 
    * at http://cr.yp.to/snuffle.html (http://cr.yp.to/snuffle/salsa20/ref/salsa20.c)
    * 2014/20/02 
    */