#!/bin/sh
#
# easybox_keygen.sh (c) 2012 GPLv3
#
# www.wotan.cc
# 

MAC=$1

# Take the last 2 Bytes of the MAC-Address (0B:EC), and convert it to decimal.

take5=${MAC:12}
last4=${take5/:/}

# Fill up to 4 places with zeros, if necessary:
deci=$(printf "%04d" "0x$last4" | sed 's/.*\(....\)/\1/;s/./& /g')
#echo M4: ${deci[@]}
#
# The digits M9 to M12 are just the last digits (9.-12.) of the MAC:
hexi=$(echo ${MAC:12:5} | sed 's/://;s/./& /g')
#echo 'M4 (Hex): ' ${hexi[@]}
# K1 = last byte of (d0 + d1 + h2 + h3)
# K2 = last byte of (h0 + h1 + d2 + d3)
c1=$(printf "%d + %d + %d + %d" ${deci:0:1} ${deci:2:1} 0x${hexi:4:1} 0x${hexi:6:1})
c2=$(printf "%d + %d + %d + %d" 0x${hexi:0:1} 0x${hexi:2:1} ${deci:4:1} ${deci:6:1})
K1=$((($c1)%16))
K2=$((($c2)%16))
#printf "K1: %x\n" $K1
#printf "K2: %x\n" $K2
X1=$((K1^${deci:6:1}))
X2=$((K1^${deci:4:1}))
X3=$((K1^${deci:2:1}))
Y1=$((K2^0x${hexi:2:1}))
Y2=$((K2^0x${hexi:4:1}))
Y3=$((K2^0x${hexi:6:1}))
Z1=$((0x${hexi:4:1}^${deci:6:1}))
Z2=$((0x${hexi:6:1}^${deci:4:1}))
Z3=$((K1^K2))
printf "%x%x%x%x%x%x%x%x%x\n" $X1 $Y1 $Z1 $X2 $Y2 $Z2 $X3 $Y3 $Z3 | tr a-f A-F