thanks for clarifying, david. i myself was wondering if that was thecase, but i guess i forgot what those other commands were actuallydoing... [hits head on table] ~ brad. On 10/25/05, David <shadoweyez@xxxxxxxxx> wrote:> FYI the command>> head -c 2925 /dev/random | uuencode -m - | head -n 66 | tail -n 65 \> | gpg --symmetric -a >/a/usbstick/keyfile.gpg>> produces a key that will work with AES128, 192, 256 or other cipher you> use it with; it is independent of the cipher. Because of the "head" and> "tail" commands being used, you could type head -c 10000000 ... and> still end up with a key of the same size. I tried this once and any> value equal to or over 2925 will not change the size of the key, because> head and tail concatenate the output.>> When I setup loop-aes I used a patched version of gpg (the patch that> came with loop-aes) as well as the --cipher-algo=AES256 option on gpg as> gpg defaults to CAST5 as the cipher.>> David>>> Marvin Lyndon wrote:> > Well, I decided to just go ahead and use AES128. Concluded that, as with> > all computing stuff, it is too easy to get carried away by the "let's go> > for the largest number" mentality whenever confronted with a choice and> > don't really know any of the details. : )> >> > With that out of the way, and just out of curiosity, could anyone clear> > up the decision of having 2925 bytes? I can tell that divided by 65 it> > means that each key will be 45 bytes long; but what is the rationale> > here? My understanding of these issues is very dim, but how does this> > number of 45 bytes relate with the use of AES128? Similarly, why would> > someone using AES256 pick 90-byte keys?> >> > Thanks for educating me,> >> > Marv> >> >> >> From: Bradley Worley <geekysuavo@xxxxxxxxx>> >> To: Marvin Lyndon <marvin.lyndon@xxxxxxxxxxx>> >> CC: linux-crypto@xxxxxxxxxxxx> >> Subject: Re: different instructions for use with aes256?> >> Date: Tue, 25 Oct 2005 15:37:49 -0500> >>> >> that code seems to work just fine, since almost all examples on the> >> net use either 2925 bytes from /dev/random or 2880 bytes. however, i> >> guess if you really want to be picky you can up it to 5850 bytes> >> (double 2925), since you are technically doubling your key sizes.> >> (it's a wild guess, really.)> >>> >> ~ brad.> >>> >> On 10/25/05, Marvin Lyndon <marvin.lyndon@xxxxxxxxxxx> wrote:> >> > Hi all,> >> >> >> > I have successfully followed all the steps in the loop-AES readme file.> >> > Since I couldn't find any reference to this, I would like to know> >> whether> >> > the step in which one creates the 65 random keys> >> >> >> > head -c 2925 /dev/random | uuencode -m - | head -n 66 | tail -n 65 \> >> > | gpg --symmetric -a >/a/usbstick/keyfile.gpg> >> >> >> > needs any modification for use in AES256 mode. Or is it enough to> >> replace> >> > all occurrences of AES128 with AES256 as one follows the README file?> >> >> >> > Thanks for any help> >> >> >> > Marv> >> >> >> > _________________________________________________________________> >> > FREE pop-up blocking with the new MSN Toolbar – get it now!> >> > http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/> >> >> >> >> >> > -> >> > Linux-crypto: cryptography in and on the Linux system> >> > Archive: http://mail.nl.linux.org/linux-crypto/> >> >> >> >> >> >> > _________________________________________________________________> > Don't just search. Find. Check out the new MSN Search!> > http://search.msn.click-url.com/go/onm00200636ave/direct/01/> >> >> > -> > Linux-crypto: cryptography in and on the Linux system> > Archive: http://mail.nl.linux.org/linux-crypto/> >> >>> -> Linux-crypto: cryptography in and on the Linux system> Archive: http://mail.nl.linux.org/linux-crypto/>>ü¸§» ܯ*m£÷+Ê›h‚¶©‡(§jwhžØ^.)îÆ̬µé€Èb½ïá¶ÚÿÿùšŠ_ç—ùbžìÿ¢¸?–)îÇ÷+Ê›h
