Links:
* Code: https://github.com/mozilla/fxa-js-client-old* Future rewrite: https://github.com/mozilla/fxa-js-client
* Key stretching details: https://wiki.mozilla.org/Identity/AttachedServices/KeyServerProtocol#Client-Side_Key_Stretching
* Key stretching performance tests: https://wiki.mozilla.org/Identity/AttachedServices/Key_Stretching_Performance_Tests