On 02/12/2014 03:30 PM, Thomas Bächler wrote: > Am 12.02.2014 15:19, schrieb Arno Wagner: >> -h is the hash that the plain-text password is put through >> to turn it into a binary value of certain defined length. >> -c specifies the hash that goes into pbkdf2 for the hash >> iteration. > > Are you sure? > > I was under the impression that '-c' only affects the cipher parameter > passed to dm-crypt - a hash would then be relevant for cipher modes like > cbc-essiv, but xts-plain64 would ignore it. Thus, cryptsetup has default > like 'aes-cbc-essiv:sha256', since essiv needs a hash, and > aes-xts-plain64, since xts does not need a hash. > > According to the manpage, -h is what is used in PBKDF2 in luksFormat > mode, or to hash the passphrase in plain mode. Yes, this is correct. The -h parameter is for LUKS header (PBKDF2 + AF splitter). For plain mode it means algorithm to use when hashing password. For -c it is cipher/mode for kernel dmcrypt (if there is a IV spec which requires hash like ESSIV, then it contains hashspec as parameter). Milan _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
