> How do they get the key

Cellebrite doesn't have a way to extract secrets from an HSM for Signal or any other app. If the secrets aren't in an HSM, then they have this new feature to automatically take advantage of that.

So Signal is still secure. Just perhaps not on a $50 Cricket phone with no HSM. But then again, neither is anything else.

> Just perhaps not on a $50 Cricket phone with no HSM.

On some more expensive devices keys can be obtained from RAM[1].

[1] https://www.cellebrite.com/en/blog/decrypting-databases-usin...

If the keys are in RAM then they aren't in an HSM- they're in RAM (as well as the HSM, but that's irrelevant).

More importantly, the app is already unlocked anyway if the keys are in RAM. So that just lets you keep it unlocked. It doesn't help you unlock an app that was locked when you got access to the device.

Indeed. It is still very useful to an investigator who has to examine an unlocked device -- in most corporate investigations this is unlikely to be an issue. Forensic examiners working for the police are likely to have more of a hard time getting codes etc., but they have access to more advanced services[1][2].

[1] https://www.msab.com/2018/12/11/msab-introduces-access-servi... [2] https://www.cellebrite.com/en/advanced-services/

Secure vs what? Or whom? Or in what scenarios? Nothing on earth "is secure" =)