Calcurse, a compact Linux organizer, now with encryption

I bumped into calcurse a while ago, but I didn't take the use of it seriously. When I started using it, I was also using Gnome's Evolution. But than, times changed, and I didn't need a calender anymore, so I gradually quit using Evolution. When two weeks ago I decide to organize my life on the computer again, I decided I would like to have a portable application I could carry on a USB stick. There was calcurse, which produces a very compact executable which I can carry around. Since it uses plain text files which are easily editable, I can also edit them on other operating systems without any problem.\ So there you have it. A small great lightweight calendar application: Calcurse !\ \ As a bonus to myself I decided to play with the idea, that I would like to encrypt the data I have on my disk on key, since it is possible that I loose my USB with lots of customers private data. So I wrote the following script, which launches the binary from the USB, decrypts the data folder, and then upon closing Calcurse would archive the data directory, encrypt it, and move it back to the USB.\ \ Notice the following things:\ 1. I use OpenSSL, this is probably lame, and I should use GPG key.\ 2. You have to do a few steps manually before you can use the script, you will find them in\ the body of the script below as comments.\

#!/bin/bash

# ENCRYPTCALCURSE.SH

# Written by Oz Nahum <nahumoz__at_you_know_where_no_spam_is_gmail.com>
# This script is distributed under the terms of the GNU Public License 
# Version 3 or later.
# You can obtaion copies of this license at:
# http://www.gnu.org/licenses/gpl.html

# A script to decrypt the calcurse_date dir, open it in 
# /home/<user>/calcurse_data
# then launch calcurse pointing to it, 
# and upon closing calcurse, encrypt the data, move it to usb stick, 
# and delete all data from /home/<user>/calcurse_data

### Begin of Script

INPUT_FILE="calcurse_d.tar.enc"
OUTPUT_FILE="calcurse_d.tar.enc"

#name of directory to encrypt (e.g. ~.calcurse)
CALCURSE_DATA_DIR="~/.calcurse/"

# usage:
# $ bash encryptCalcurse.sh 
# $ bash encryptCalcurse.sh [ecnrypted_data_in.enc] [encrypted_data_out.enc]

#TODO: test that modified script !
### Begin of Script
#make files readable only by owner
umask 077

function Config {
    USB=`pwd`
    tar -cf calcurse_data.tar $CALCURSE_DATA_DIR
    openssl aes-256-cbc -salt -in calcurse_data.tar -out calcurse_d.tar.enc
    clc=`which calcurse`
    cp -v $clc $USB

}

function cleanUp {
    find /dev/shm/calcurse_data -type f | xargs shred -fuz;
    if [ -f /dev/shm/cdt.tar ]; then
        shred -fuz /dev/shm/cdt.tar
    fi
    if [ -f /dev/shm/calcurse_data_tmp.tar ]; then
        shred -fuz /dev/shm/calcurse_data_tmp.tar
    fi
    rmdir /dev/shm/calcurse_data/notes
    rmdir /dev/shm/calcurse_data
}

function readData {
#first decrypt the data
openssl enc -d -aes-256-cbc -salt -in $INPUT_FILE -out /dev/shm/calcurse_data_tmp.tar
echo "extracting data"
#silently extract data, no need for verbose output (v flag)
tar -C /dev/shm -xf /dev/shm/calcurse_data_tmp.tar
#note unpacking removes the original tar
}

function encryptData {
openssl aes-256-cbc -salt -in /dev/shm/cdt.tar -out calcurse_d.tar.enc
}


case "$1" in
    "")
    echo "expecting parameter input... see header of script for usage"
    ;;
    "--config")
        CALCURSE_DATA_DIR=$2    
        Config
    ;;

    "--read")
        trap "cleanUp" SIGHUP SIGINT SIGQUIT SIGKILL SIGABRT SIGTERM EXIT
        # when calcurse is done tar the direcotry
        readData
        calcurse -D /dev/shm/calcurse_data
        tar -cf /dev/shm/cdt.tar -C /dev/shm/ calcurse_data/

        # then encrypt
        # if encryption failed $? == 1 so repeat it again ...
        encryptData
        es=$?
        while [ "$es" = "1" ]; do 
            echo "encrypting data"
            encryptData
            es=$?    
        done
    ;;
    "--decrypt")
        readData
    ;;
    "--encrypt")
        tar -cvf /dev/shm/cdt.tar -C /dev/shm/ calcurse_data/
        encryptData
    ;;

        #if encryption succeeded clean up by calling the function
        #cleanUp

esac
#note about the salt option note found in openssl man page[1],[2]
#note about lack of compresion with ssl [3]

#sources:
#[1]http://ubuntuforums.org/showpost.php?p=8287351&postcount=9
#[2]http://linux.die.net/man/1/enc
#[3]http://serverfault.com/questions/17855/can-i-compr:ess-an-encrypted-file