Allo offers two chat modes: normal and incognito. In normal mode, an artificial intelligence run by Google (but no humans including the Allo team or anyone at Google) can read your messages. Incognito mode encrypts messages when they are in transit or at rest, and will be deleted as soon as they’re delivered. Simply Secure did a study where they asked a group of users what they think about secure messaging in mobile apps. This is what users actually need when it comes to privacy.”]
Source: https://vnhacker.blogspot.com/2016/05/security-and-privacy-in-google-allo.html