[MI400] How does it do ?

["Cros, Jean-Francois" <jean-francois.cros@xxxxxxx>]

To store the password, we know (chapter 14 ;-)) that user's name are
encrypted and stored using the password as key in an "altered" form to reach
the 56 bits needed by the DES encryption algorithm. I think (may be I'm
wrong) that it's impossible to decypher the encrypted string to obtain
directly a clear and readable password.

So, I don't understand how the OS/400 do to control the rule based on the
QPWDPOSDIF.
In other words,  how the OS/400 do to tell me that there is a "same
character in same position as previous password" (CPF22C8) when I want to
change my current password ?

Thank you all,
Jean-François.