stolo93 / steganography

Assignment for C language class at BUT FIT

School asignment for IJC class

Main language: C

Main programs:

primes.c

prints out last 10 prime numbers less than 300 000 000 for which it uses the Sieve of Eratosthenes build generates two files:

• primes - uses macros for operations on bitsets
• primes-i uses inline functions for the same thing

steg-decode.c

prints secret message hidden in du1-obrazek.ppm

• secret message is hidden at LS bits of bytes located at prime number indexes (starting with 29)
• every eight LSB make up to one byte of the secret starting with LSB

Build

Usage:

• make to build all executable files
• make run to build and run primes and primes-i
• make zip to create a zip (just for the assignement)
• make clean to clean all build files

Try running:

make && ./steg-decode du1-obrazek.ppm

to reveal the secret message hidden in the picture