This is used to secure the cookies. Encryption keys and message
   authentication keys are derived from this using one-way functions.
   Changing it will invalidate all sessions.

   Number of seconds for which the session may be considered valid. If
   cookie_duration is not set, this is used instead to expire the session
   after a period of time, regardless of the length of the browser
   session. It is unset by default, meaning that sessions expiration is
   not capped.

SYNOPSIS

     # In Dancer 2 config.yml file

     session: Cookie
     engines:
       session:
         Cookie:
           secret_key: your secret passphrase
           default_duration: 604800

DESCRIPTION

   This module implements a session factory for Dancer 2 that stores
   session state within a browser cookie. Features include:

     * Data serialization and compression using Sereal

     * Data encryption using AES with a unique derived key per cookie

     * Enforced expiration timestamp (independent of cookie expiration)

     * Cookie integrity protected with a message authentication code (MAC)

   See Session::Storage::Secure for implementation details and important
   security caveats.

SEE ALSO

   CPAN modules providing cookie session storage (possibly for other
   frameworks):

     * Dancer::Session::Cookie -- Dancer 1 equivalent to this module

     * Catalyst::Plugin::CookiedSession -- encryption only

     * HTTP::CryptoCookie -- encryption only

     * Mojolicious::Sessions -- MAC only

     * Plack::Middleware::Session::Cookie -- MAC only

     * Plack::Middleware::Session::SerializedCookie -- really just a
     framework and you provide the guts with callbacks

     * Dancer2::Core::Role::SessionFactory -- documentation of the base
     package, some more attributes to configure the cookie

POD ERRORS

   Hey! The above document had some coding errors, which are explained
   below:

   Around line 1:

     Unknown directive: =attr

   Around line 7:

     Unknown directive: =attr