[OT] Algorithm question

[Keith Willis]

I know, I know... somewhat off topic, but I'm certain some of you
people have done what I'm trying to do many times!

I am implementing (for my clients) a 'common front end' for a number
of different symmetric ciphers, and am stuck on how to implement
correctly the so-called "Cipher Text Stealing" method of dealing with
a final, incomplete, block in CBC mode.

I have read the description in Schneier's Applied Cryptography
(pp195-196 in the 2nd Edition), but I just can't seem to get my head
around it.  I would be most grateful if someone could point me at a
sample implementation or even just some pseudo-code.

My thanks in advance.
klw
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