This module implements a secure way to encode session data. It is primarily
intended for storing session data in browser cookies, but could be used with
other backend storage where security of stored session data is important.

Features include:

    () Data serialization and compression using Sereal
    () Data encryption using AES with a unique derived key per encoded session
    () Enforced expiration timestamp (optional)
    () Integrity protected with a message authentication code (MAC)