As an old user of textsecure they’ve been solid for a surprising amount of time. Back in the day (ca like 2013?) me and all my friends would use CyanogenMod which at the time had textsecure built in to the ROM. It used an early version of the Signal encryption protocol layered onto plain SMS messages, and the ROM support meant I didn’t even need to install a special app - it would intercept all incoming and outgoing SMSes at the OS level and transparently encrypt and decrypt each one based on who it was coming from or going to. Since messages were direct, the textsecure servers afaik were only used to host public keys.
Also since it was layered onto SMS, we had a handful of fun occurrences of re-flashing ROMs and forgetting to re-register and then we’d get gibberish texts from our friends whose phones still had our old key.
As an old user of textsecure they’ve been solid for a surprising amount of time. Back in the day (ca like 2013?) me and all my friends would use CyanogenMod which at the time had textsecure built in to the ROM. It used an early version of the Signal encryption protocol layered onto plain SMS messages, and the ROM support meant I didn’t even need to install a special app - it would intercept all incoming and outgoing SMSes at the OS level and transparently encrypt and decrypt each one based on who it was coming from or going to. Since messages were direct, the textsecure servers afaik were only used to host public keys.
Also since it was layered onto SMS, we had a handful of fun occurrences of re-flashing ROMs and forgetting to re-register and then we’d get gibberish texts from our friends whose phones still had our old key.