For academic purposes I am analyzing the /etc/shadow
file at Ubuntu Desktop 22.04.
I did do realize for this 22.04 that for any user created through the adduser
command - which behind the scenes is used the passwd
command - the /etc/shadow
file always shows the encrypted password for those users starting with $y$j9T$
.
Now, this machine came from two full upgrades, 18.04 and 20.04, where the first user created from the beginning of the installation (18.04) has his encrypted password starting with $6$
. It in the /etc/shadow
file
Question
- Is there an official resource for either the
passwd
command or/etc/shadow
file indicating the encryption algorithm applied with its respective starting pattern according the OS version?
Something like (invalid data of course)
Ubuntu Desktop 18.04 - md5 - $6$Ubuntu Desktop 20.04 - sha256 - $csdf$Ubuntu Desktop 22.04 - bcrypt - $y$j9T$