Autofs script to automount LUKS encrypted disks. Based on http://msqr.us/m2/archives/2009/07/configuring-automount-for-luks.html

auto.luks

#!/bin/bash
# This file must be executable to work! chmod 755!
#
# The LUKS key must exist as a file at /etc/.keys/${device}.key
# Protect this directory: root as user/group, 400 as permissions
#
# Edit your autofs master file to include something like
# /mnt/crypt    /etc/auto.luks    --timeout=600
#
# Then you can access your LUKS encrypted disk with
# cd /mnt/crypt/<device>
#
# Combine it with udev rules to have meaningful device name
#
# /!\ This crypt does not handle LUKS unmapping, see the other file

device=$1
device_crypt=${device}_autocrypt

CRYPTSETUP=/sbin/cryptsetup

mountopts="-fstype=ext4,defaults,noatime,nodiratime"

# map the LUKS device, if not already done
$CRYPTSETUP luksOpen /dev/${device} ${device_crypt} -d=/etc/.keys/${device}.key 2>/dev/null

echo $mountopts :/dev/mapper/${device_crypt}

auto_umap_luks.cron

#!/bin/bash
# This file must be executable to work! chmod 755!
#
# This script will close LUKS filesystem if not in use
#
# Install in cron to run regularly

CRYPTSETUP=/sbin/cryptsetup

shopt -s nullglob
for dev in /dev/mapper/*_autocrypt
do
    match=`mount|grep $dev`
    if [ -z "$match" ]; then
        # fs is not mounted, LUKS fs can be closed
        dm_file=${dev##*/}
        $CRYPTSETUP luksClose $dm_file
    fi
done