Re: Encryption algorithm used for the IBMi OS passwords.

John,

Regarding my concern about those who have vested financial interests in
promoting publicly disclosed algorithms - I hope you're not taking my
comments too personally. You and others have been raising points in this
discussion which I've heard for years, which shows that their marketing has
been effective.

Regarding lost keys, an extreme example would be having all ones data
encrypted with a key-based algorithm, then say losing the key to the
repository which holds the encryption keys. You're stuck without having any
way to decipher your data. You've effectively lost all your data. I raise
the point for the sake of discussion - not that I advocate for back doors.

Regarding algorithms, whether publicly disclosed or not, their
implementations could include say spyware without the public knowing about
it. So other factors should be employed to assure trust in the source.

Given the era and the context of Kerckhoff's 2nd tenet, it's pretty clear
that he was advocating for key based encryption. Cryptography devices at
the time were crudely mechanical and prone to fall into enemy hands. There
was no point in hiding how they worked. But that's a far cry from "calling"
for public disclosure of algorithms.