It’s not natively supported by the base RCS standard, in the section at the end of the paper in the section titled “Third Party RCS Clients” Google explains that they’ve built the e2ee their Messages app themselves, (on top of standard RCS).
A developer has to use Google’s implementation specifically in order to send and recieve e2ee messages to Google’s Messages app (and Samsung Messages who also implemented this recently)
Although the e2ee implementation is using the Signal protocol under the hood, it’s for message content only - this is what is transmitted in cleartext (taken from the paper)
Phone numbers of senders and recipients
Timestamps of the messages
IP addresses or other connection information
Sender and recipient’s mobile carriers
SIP, MSRP, or CPIM headers, such as User-Agent strings which may contain device manufacturers and models
Whether the message has an attachment
The URL on content server where the attachment is stored
Approximated size of messages, or exact size of attachments
Without using this implementation of the Signal protocol on top of RCS, the message will deliver to the contact’s phone, but shows up as unencrypted garbled text
That is a very useful resource though, never knew there was a paper available on the implementation. Saving 😁
If only there was a secure and open standard that would work on any platform, regardless of ecosystem…
Oh well!
If you are talking about RCS - the encryption aspect is a google proprietary extension
True, but the Apple RCS announcement said that they were going to work with the GSM association and google to build it into the base spec
Thought RCS used the Signal Protocol?
Edit for source: Technical paper: Messages end-to-end encryption
It’s not natively supported by the base RCS standard, in the section at the end of the paper in the section titled “Third Party RCS Clients” Google explains that they’ve built the e2ee their Messages app themselves, (on top of standard RCS).
A developer has to use Google’s implementation specifically in order to send and recieve e2ee messages to Google’s Messages app (and Samsung Messages who also implemented this recently)
Although the e2ee implementation is using the Signal protocol under the hood, it’s for message content only - this is what is transmitted in cleartext (taken from the paper)
Without using this implementation of the Signal protocol on top of RCS, the message will deliver to the contact’s phone, but shows up as unencrypted garbled text
That is a very useful resource though, never knew there was a paper available on the implementation. Saving 😁
Signal
The problem is actually getting people to use it since they’re all too busy arguing over the color of a message