Re: Encryption on the AS/400

From: <David.X.Kahn@gsk.com>

> If I were buying a commercial encryption package I would
> expect to be able to use it to send data backwards and forwards
> between myself and any number of partners.

It seems that many comments in this thread pertain to the market for
encryption.  That's fine.  Except we're thinking on different levels.  My
interest was primarily with the strength of encryption rather than it's
marketability.

For example, a public algorithm is more marketable than a private one.  A
public algorithm provides a basis for discussion and challenge by a
community of professional cryptographers.  And with a public algorithm (a
marketable one), the security is solely in the key.

On the other hand, the U.S. military deploys private algorithms in it's
systems.  I assume they consider it to be more secure.

> If I simply wanted to encrypt data on my local machine
> I could knock up a program in about an hour that would
> give me 100% uncrackable encryption. Simply use a
> random key the same length as the data to be protected.
> XOR each byte of the message with the corresponding
> byte of the key.

It seems to me that the hard part with this method is generating /
maintaining a truely random key that is the same length as your data.  What
if you need to encrypt large files?

Nathan M. Andelin
www.relational-data.com