Källa
How Google chat features keep your conversations secure - Messages Help
How we protect your data
Chat features by Google uses Transport Layer Security (TLS) encryption to protect your messages. This means that anyone trying to intercept your messages between you and Google would only be able to see encrypted, unreadable text.
How and why your data is temporarily stored
RCS messages you send using Google’s RCS backend are temporarily queued for delivery and deleted after they’re delivered. For undelivered RCS messages, you can switch to SMS or MMS provided by your carrier, in which case the corresponding RCS message is deleted from the queue.
Google’s RCS backend sends and temporarily stores files like images, videos, GIFs, and stickers with random, unguessable URLs. These links aren't shared with you or the person receiving your message. To prevent connections between the hosted file and your phone number, Google uses a special algorithm (hash function) that transforms these URLs and makes it very difficult to associate the file and your phone number.
Click to expand...