* Herbert Xu | 2010-02-09 18:37:18 [+1100]: >Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: >> >> You should rather add a flag CRYPTO_ALG_CHANGES_STATE to determine that a >> cipher can't be used to encrypt disks. > >No, please see my reply in the previous thread. What we should >do is fix arc4. I just haven't got around to doing it yet. > >As to blacklisting algorithms not suitable for disk encryption, >that is up to the dm-crypt maintainers to decide. Herbert, what happend to the "check for streamcipher" idea you had? Is it gone? On the other hand it wouldn't be probably that bad to have a seprate interface to grab a block cipher _or_ a stream cipher. So something like this wouldn't happen. This is basically the "check for stream cipher" without encrypt = decrypt plus with a struct the cra_u union. I can't imaging how you want to fix arc4 that it will work in dm-crypt. The algorithm relies more or less on the fact that it envolves itself during processing of data. Salsa works with dm-crypt because the internal state is taken from the IV and is never written back. dm-crypt always encrypts/decrypts a 512 block in one go. Splitting it in two and requesting two 256 block encryptions would work with _every_ other block cipher but break salsa. > >Cheers, Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
