TO COMPILE: make
TO CLEAN: make clean
TO ENCRYPT (Assumnig key.txt is key file, plaintext.txt is the file you want to encrypt, and ciphertext.hex is the file you want to write the ciphertext to): ./crypt -e key.txt plaintext.txt ciphertext.hex
TO DECRYPT: ./crypt -d key.txt ciphertext.hex recovered_plaintext.txt