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Date: Tue, 14 Oct 2014 23:16:24 +0200
From: Jonas Meurer <jonas@freesources.org>
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Subject: Re: [dm-crypt] LUKS disk encryption with remote boot authentication
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To: dm-crypt@saout.de

Hi Cpp,

Am 14.10.2014 um 13:42 schrieb Cpp:
> I'm interested in a solution for devices with LUKS disk encryption
> that use a remote server to securely obtain a decryption key upon
> boot. Let me elaborate: Suppose I have an embedded device i.e.
> Raspberry Pi with an external USB HDD or maybe a Cubieboard with a
> SATA-attached disk. The rootfs is located on an encrypted partition on
> the disk that has to be decrypted before the OS can boot. The boot
> partition is located on an unencrypted NAND/SD partition.
> 
> Normally a modern linux distro will ask the user to type in the
> password via a keyboard upon boot, if disk encryption is being used. I
> am however interested in setups where this decryption key is obtained
> securely (TLS?) from a remote (secure) server via LAN.
> 
> Are there any known setups like this that I can take a look at?

Debian and Ubuntu cryptsetup packages (at least, I don't know about
other distributions) support remote unlocking in initramfs. It works the
following way: the dropbear ssh server ist started in initramfs, you ssh
into the initramfs and unlock the root partition, afterwards the boot
process is continued. See section 8. of README.Debian in the
distribution packages[1] for further information.

Cheers,
 jonas

[1] or: here
http://sources.debian.net/src/cryptsetup/2:1.6.6-2/debian/README.Debian/#L202