Here's a purely software question...

I am implementing a data block encryption algorithm using a CRC-CCITT
style filter. The SR is preloaded with a key. The clear text is shifted
into the SR one bit at a time, and the msb of the SR gives each clear
text bit it's encrypted equivelant.

Now here's the question: If I use the above algorithm what is the
inverse method? How does one convert it back? I'm pretty sure that it is
possible as their are no folded (lost) states.

I hope someone has a pointer to a solution for me. Thanks.

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Regards, Dana Frank Raymond