Re: detached LUKS header size
Milan Broz <[email protected]>
| Newsgroups | gmane.linux.kernel.device-mapper.dm-crypt |
|---|---|
| Message-ID | <[email protected]> |
On 25/11/2019 16:17, Fourhundred Thecat wrote: >> On 2019-11-25 14:55, Milan Broz wrote: > > Hi Milan, > > just to make sure there is no misunderstanding: > >> Then there is alignment, so the real data offset is aligned by default to >> the 1MB boundary. >> >> With this padding, header size is for 128bit key 2MB, for 256/512 key 4MB. > > I am actually using 512 bit key: > > --cipher aes-xts-plain64 --key-size 512 --hash sha512 > > so it would seem I need 4MB header for luks1 with 512 key > >> Yes. For reference: for 128bit it is 528384 bytes, for 256bit 1052672 >> bytes, >> for 512bit (2x256bits in XTS mode) it is 2068480 bytes. > > now I am confused. 2068480 is less than 2MB. So when aligned to 1MB > boundary, 2MB would be enough for luks1 with 512 key. > > So is it 2MB or 4MB ? Ah, yes, sorry, it is 2MB. (The real used space is 4040 512-byte sectors.) Milan _______________________________________________ dm-crypt mailing list [email protected] https://www.saout.de/mailman/listinfo/dm-crypt