Firmware hacking: Entropy of a header file #1

Thursday, February 17, 2011

$ java ByteEntropy -c -r 512 -w 200 -o assert.h.ent -f /usr/include/assert.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' assert.h.ent

Entropy average: 42.3333

$ java ByteEntropy -c -r 512 -w 200 -o crypt.h.ent -f /usr/include/crypt.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' crypt.h.ent

Entropy average: 42.25

$ java ByteEntropy -c -r 512 -w 200 -o elf.h.ent -f /usr/include/elf.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' elf.h.ent

Entropy average: 41.5422

$ java ByteEntropy -c -r 512 -w 200 -o inttypes.h.ent -f /usr/include/inttypes.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' inttypes.h.ent

Entropy average: 36.3043

$ java ByteEntropy -c -r 512 -w 200 -o math.h.ent -f /usr/include/math.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' math.h.ent

Entropy average: 38.6452

$ java ByteEntropy -c -r 512 -w 200 -o stdio.h.ent -f /usr/include/stdio.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' stdio.h.ent

Entropy average: 40.8667

$ java ByteEntropy -c -r 512 -w 200 -o stdlib.h.ent -f /usr/include/stdlib.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' stdlib.h.ent

Entropy average: 41.4769

$ java ByteEntropy -c -r 512 -w 200 -o time.h.ent -f /usr/include/time.h

$ awk -F',' '{s+=$1} END {printf "Entropy average: %s\n", s/NR}' time.h.ent

Entropy average: 40.8462

Firmware hacking