cipher feedback mode
Paul Rubin <[email protected]>
| Newsgroups | gmane.comp.python.cryptography |
|---|---|
| Message-ID | <[email protected]> |
I see the Java cipher api accepts feedback sizes down to 1 byte (8 bits) in CFB mode, but nothing smaller than that. However, the NIST test vectors for AES have some for 1-bit CFB mode. Does anyone care about 1-bit CFB mode? How about 2 bits or 4 bits? Is there any valid use for CFB mode where the feedback size doesn't divide the block size, like 5 bits or 23 bits? What should be done about padding the final plaintext, when the feedback size is smaller than the block size? Is it ok to just require that the total plaintext consist of an integer number of feedback units in those cases? What about the full-block case? I'm trying to think of what software applications use CFB mode at all. Anyone know of any? Thanks --Paul