Keyfile Generator

#!/bin/bash
#random random keyfile generator

ARGS=6
E_BADARGS=85


if [ $# -ne "$ARGS" ]
then
    echo
    echo "Usage: `basename $0` [keyfile_name] [extension] [amount] {bytes} {min-count} {max-count}"
#   echo "Notice: [sudo apt-get install randomsound] before use"
    echo "uses dd with /dev/urandom"
    echo
    echo "Example: `basename $0` picture jpg 10 1024 512 4096"
    echo "--will make directory named picture_10"
    echo "--with 10 keyfiles named picture1.jpg to picture10.jpg"
    echo "--keyfile size will be random between .52MB & 4.19MB"
    echo
    exit $E_BADARGS
fi

filename=$1
extension=$2
amount=$3
bytes=$4
count_min=$5
count_max=$6


echo
#echo "Restarting entropy with randomsound (doesn't always have the best entropy from startup)"
#sudo /etc/init.d/randomsound restart

mkdir "$filename"_"$amount"

maxsize=`echo "$bytes*$count_max*.000001" | bc`
minsize=`echo "$bytes*$count_min*.000001" | bc`
echo
echo "MIN: $minsize""MB"" MAX: $maxsize""MB"

for a in `seq $amount`
do
    echo
    entropy1=`cat /proc/sys/kernel/random/entropy_avail`
    echo -n "Making $filename$a.$extension with entropy of:$entropy1"

    number=0
    FLOOR=$count_min
    RANGE=$count_max

    #initialize random number range
    while [ "$number" -le $FLOOR ]
        do
            SEED=$(head -1 /dev/urandom | od -N 1 | awk '{ print $2 }')
            RANDOM=$SEED
            number=$RANDOM
            let "number %= $RANGE" # Scales $number down within $RANGE.
        done

    currentfilesize=`echo "$bytes*$number*.000001" | bc`    #helpful for large ones

    echo " will be $currentfilesize""MB"
    echo "dd if=/dev/urandom of=./"$filename"_"$amount"/"$filename""$a"."$extension" bs=$bytes count=$number"

    dd if=/dev/urandom of=./"$filename"_"$amount"/"$filename""$a"."$extension" bs=$bytes count=$number

    entropy2=`cat /proc/sys/kernel/random/entropy_avail`
    totale=`echo "$entropy1-$entropy2" | bc`

#   echo ".:: Pausing to generate more entropy ($totale used $entropy2 left) ::."
#   sleep 3

    echo
done

echo "Made $a keyfile(s) in /""$filename""_""$amount"
echo

exit 0