Dennis cryptically asks:

> I'm looking for some help from the MPE veterans out there.  I'm researching 
> encryption libraries for the MPE platform.  Does anyone know of a library (
> either commercial or open source gpl) that works on MPE?  
>   
>  I'm specifically looking for an encryption algorithm like Blowfish that 
will 
> encrypt data in the same footprint as the original data.  i.e. Start with 
16 
> bytes unencrypted, when it's encrypted, it's still 16 bytes.

If no one but you is ever going to need to the know the encryption algorithm, 
by far the easiest thing to do is to use an XOR encryption procedure. In this 
process, you take a string of some random length and XOR it with your data, 
byte-by-byte. The result is exactly the same length as the original. More than 
that, it's extremely fast.

How do you then decrypt the string? Surprisingly, you take the same 
encrypting string and XOR it with the encrypted data once again. Voila. You get your 
original data back.

If you adopt this algorithm, all you need do is never let anyone know the 
encrypting string. If you don't share that string, it's a pretty tough little 
procedure to defeat -- so long as you don't use a common phrase to encrypt your 
data with.

Wirt Atmar

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