You should be able to lock that down to “only while the messaging app is in the foreground”, which limits the exposure time further, but certainly not to zero.

You should be able to lock that down to “only while the messaging app is in the foreground”, which limits the exposure time further, but certainly not to zero. Hopefully, if you care about this, you use and app which can be configured to have its own passphrase/pin which hopefully is used to access properly secured keys from the Secure Enclave only when that’s entered. (Signals interface works like this. I’m only assuming/hoping it’s working that way underneath).