Prestashop: Generate and Change Cookie Key

According just random generate of character 56 and 8. The cookie key within settings.inc.php

array(‘_COOKIE_KEY_’, Tools::passwdGen(56)),
array(‘_COOKIE_IV_’, Tools::passwdGen(8)),

If you want to change your Cookie Key, you should have problem enter the admin page. Here the recovery method:

1. Copy your cookie key from /config/settings.inc.php, for example :
   zhNXco9AkmOMkXSA1UJvRLT0oy1K0bImRwhAjXHdIVexfO18ZyFzwsLL
2. Go to http://www.md5.fr/
3. In the field, paste the cookie key and type IMMEDIATELY after, without space, your password, for example :
   zhNXco9AkmOMkXSA1UJvRLT0oy1K0bImRwhAjXHdIVexfO18ZyFzwsLLadminshop
4. Generate the MD5 hash.
5. Copy it.
6. Paste it in the passwd field of the ps_employee table, for your admin user.

source: http://www.prestashop.com/forums/viewthread/22045/