[dm-crypt] cryptsetup problem on Raspberry Pi 2 w 512bit key-size (works on Raspberry Pi 1, x86_64, 256bit)

Johannes Ernst johannes.ernst at gmail.com
Fri Feb 20 22:37:08 CET 2015

    cryptsetup --hash sha512 --key-size 512 -v luksFormat ./test.img
cannot be opened again on the new Raspberry Pi 2. Shorter key-size, and other platforms work.

This is a bit a puzzler to me …

This is what I do:
    # Create 8M image
    dd if=/dev/zero of=./test.img count=8 bs=1M
    # Set up encryption -- enter a suitable password when asked
    cryptsetup --hash sha512 --key-size 512 -v luksFormat ./test.img
    # Now attempt to open it, entering the same password
    cryptsetup open test.img test

and indeed it works for me on x86_64, the Raspberry PI 1, and the BeagleBone Black. However, it fails on the Raspberry Pi 2 with:
	"No key available with this passphrase."

If I create the encrypted image on the Raspberry Pi 2, I can open it on other platforms. However, I cannot open any image with these parameters on the Raspberry Pi 2, regardless where it was created.

If I set the key-size to 256 bit, it works on all platforms.

The Raspberry Pi 2 is an ARM v7 processor, unlike the Raspberry Pi 1. But then, the BeagleBone Black is Arm V7, too.

Puzzled ...


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