I just went through the install process specifying "do something else," then picked my partition to use as an encrypted container, and finally used that container to be formatted with a filesystem. I didn't see an option to use the cipher of my choosing and noted that the default appears to be sha256
.
Is there a way to tell it what I want to use?
Edit: this was using the 16.10 desktop iso.
Edit2: given AlexP's example table below, I thought I'd list the actual defaults after going through the Ubuntu installer as described above.
Edit3: supplementing with what I think shows that Arch's recommendations and the Ubuntu defaults perhaps don't differ at all.
The only thing that stands out is the payload offset and anecdotally I perceive that the ubuntu drive opens faster. I think this may be because of it's option for --iter-time
. The default is 2000
(milliseconds) and I would have specified 5000
manually. This is how long it churns before arriving at the final hash if I understand correctly. Every time you unlock, you have to do this again to get the right password hash (correct if wrong). Other than that, things are identical.
### ubuntu default
$ sudo cryptsetup luksDump
Version: 1
Cipher name: aes
Cipher mode: xts-plain64
Hash spec: sha256
Payload offset: 4096
MK bits: 512
### arch recommendation
$ sudo cryptsetup luksDump
Version: 1
Cipher name: aes
Cipher mode: xts-plain64
Hash spec: sha256
Payload offset: 65535
MK bits: 512
### ubuntu default
$ sudo cryptsetup status /dev/mapper/ubuntu
type: LUKS1
cipher: aes-xts-plain64
keysize: 512 bits
device: /dev/sdb2
offset: 4096 sectors
size: 487393280 sectors
mode: read/write
### arch recommendation
$ sudo cryptsetup status /dev/mapper/arch
type: LUKS1
cipher: aes-xts-plain64
keysize: 512 bits
device: /dev/sda2
offset: 65535 sectors
size: 233262018 sectors