WhatsApp Tri-Crypt

WhatsApp Tri-Crypt (also known as Omni-Crypt) is an application that lets you decrypt (and encrypt) WhatsApp database files. This means that it lets you backup files in .crypt5, .crypt6, .crypt7, and .crypt8 format.

Basically, WhatsApp Tri-Crypt aims to help you recover WhatsApp conversations that were deleted from the device, with the goal (presumably) of finding out who a person had conversations with, or what about. Basically, it's an app for spying.