On Wed, 26 Jul 1995, Johnathan Corgan wrote:
Another, more crypto related question--how to deal with IV's? Right now, I'm using 512 byte sectors with CBC. For each sector, the IV is the sector number. This frustrates the known plaintext attack issue, but I'm not sure if such a simple scheme is really effective. Probably not.
Your scheme should be OK. If you'd chosen the same IV for each sector then identical sectors would encrypt the same. If I remember rightly then having a known IV only affects the security of the first block, after that the ciphertext chaining comes into effect. - Andy +-------------------------------------------------------------------------+ | Andrew Brown Internet <asb@nexor.co.uk> Telephone +44 115 952 0585 | | PGP (2048/9611055D): 69 AA EF 72 80 7A 63 3A C0 1F 9F 66 64 02 4C 88 | +-------------------------------------------------------------------------+