Google Contact Keys preps automatic RCS key-origin checks

An unreleased feature in Google Contact Keys v1.443.978654235 adds automatic checks comparing RCS server keys with keys created on participants' devices, including verification history and man-in-the-middle warnings. A self-audit will also compare device keys against those stored on the RCS server.

• The feature compares RCS server keys with keys on participants' devices
• Mismatches trigger a warning about possible man-in-the-middle attacks
• A self-audit checks device keys against those stored on the RCS server
• Older RCS protocols may not support key-origin checking