Docs on string-to-key routines?

[Jeffrey Hutzelman]

On Thursday, March 11, 2004 16:38:46 -0800 "Henry B. Hotz" 
<hotz at jpl.nasa.gov> wrote:

> Where is the "real" description of the string-to-key functions, V4, AFS,
> and V5?
>
> My specific question is whether any of them have hard upper bounds on
> password length.  Saw a reference that seemed to imply they were
> encryption type specific, but I can't find it again (and that doesn't
> seem quite right in any case). --


String-to-key operations are indeed enctype-specific -- they need to be, 
since they must produce a key that is valid for the enctype in use.

Specifications for the string-to-key algorithms for standards-track 
Kerberos 5 enctypes can be found in

draft-ietf-krb-wg-crypto-07.txt
draft-raeburn-krb-rijndael-krb-05.txt


"Standard" Kerberos 4 supports only single-DES encryption.  The 
string-to-key function is the same as that described in 
draft-ietf-krb-wg-crypto-07.txt for DES-CBC-CRC, with the salt string and 
parameter block both empty (krb4 does not salt keys).


AFS supports only the single-DES enctype.  The AFS string-to-key function 
is not documented; you'll have to read the source.


All of these functions support input of essentially unlimited length.


-- Jeffrey T. Hutzelman (N3NHS) <jhutz+ at cmu.edu>
   Sr. Research Systems Programmer
   School of Computer Science - Research Computing Facility
   Carnegie Mellon University - Pittsburgh, PA