The default password hashing algorithm has been changed in Debian (and
thus Ubuntu) with the Bullseye release. pam_unix has changed to
using yescrypt instead of sha512.
This went pretty fast. The change in pam went into unstable
February and it landed in testing in time for the release of
Bullseye in August and thus becoming stable:
- pam-configs/unix: Default to yescript rather than sha512. From a theoretical security standpoint, it looks like yescript has similar security properties, assuming (as we typically do in the crypto protocol community) that sha256 is still reasonable. However, in terms of practical resistant to password cracking, particularly in terms of valuing space complexity as well as time complexity, yescript is superior,
References: * https://www.debian.org/releases/bullseye/mips64el/release-notes/ch-information.en.html#pam-default-password * https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=978553 * https://tracker.debian.org/news/1226655/accepted-pam-140-3-source-into-unstable/
