[dm-crypt] How to recognize a LUKS container

Arno Wagner arno at wagner.name
Tue Sep 22 22:13:31 CEST 2015


it is very easy:

- cryptsetup isLuks <container> returns true
- the container starts with the LUKS magic number, i.e.
  'L','U','K','S', 0xBA, 0xBE.

On Tue, Sep 22, 2015 at 20:52:16 CEST, H McCurdy wrote:
> Hi,
> I've read the FAQ (but can't guarantee I didn't miss something).  In the
> warnings sections about the Ubuntu installer I read "...  (it is very easy
> to recognize a LUKS container)..."

Always good to know it gets read!

> I don't actually need to know, but I'd like to know how this is done.  I
> didn't find the answer in the FAQ, didn't find it using Google and didn't
> find it on Stack Overflow.

It is really very easy, both using cryptsetup and manyally:

- "cryptsetup isLuks <container>" returns true
  use option -v for additional text output.

- The container starts with the LUKS magic number, i.e.
  'L','U','K','S', 0xBA, 0xBE.

The reference for the second one would be the Luks Specification,
available here:


(It is referenced in the FAQ at the end).


Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno at wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
A good decision is based on knowledge and not on numbers. -- Plato

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"news" is "something that hardly ever happens." -- Bruce Schneier

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