shadow

# andrew <andrewjkerr>
# location
/etc/shadow

# fields
username
salt and hashed password
days since epoch of last password change
days until a change is allowed
days before a change is required
days warning for expiration
days before account is inactive
days since epoch when account expires
reserved

# more on the salt/hashed password
$id$salt$hash
1: MD5
2a: Blowfish
5: SHA-256
6: SHA-512