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DES-OFB vs. DES-CFB
Posted: Mon Nov 11, 2002 6:22 pm
by ASTROMODAT
What is the difference between DES-OFB and DES-CFB? I know that they are different algorythms (and I assume incompatible), but I'm wondering how they relate to APCO 25. I know that DES-OFB is APCO 25 compatible, but what about DES-CFB, and why would one use CFB?
Larry
cfb
Posted: Mon Nov 11, 2002 8:14 pm
by CHEFA2001
CFB+ Costly F**king Board, in other words, it's what you say right after your rep tells you the price of the DES-XL, DES_OFB board.
No, seriously, I have never heard of it........
Posted: Mon Nov 11, 2002 8:37 pm
by XDCLabs.COM
The DES algorithm has many different types of "implementations". Cipher FeedBack (CFB), Output FeedBack (OFB), Electronic CodeBooK (ECB), etc. are the most common. Moto has a proprietary XL implementation that was initially designed to extend the range of audible encrypted analog audio. If you're familiar with Securenet, you've probably noticed the difference in audio quality between DES (which is CFB) and DES-XL.
As far as APCO is concerned, they have selected OFB to be the implementation method for DES as it is more of a standard than XL. CFB, on the other hand is not supported in digital mode by Moto. Not sure about the other APCO players. But considering that DES-OFB is standard, why bother with other implementations.