XOR cipher

A C implementation of the simple XOR cipher for encrypting and decrypting arbitrary files.

Clone, compile and install

git clone https://github.com/koppi/xor && sudo make -C xor release install

(Note: using simply make instead of make release will produce debug versions of the tools with the address sanitizer and undefined behavior sanitizer enabled.)

or

curl -L 'https://github.com/koppi/xor/raw/master/xor.c' | gcc -O2 -x c -o /usr/local/bin/xor -

Usage

xor -e abc.key -i abc.txt -o abc.enc # to encrypt
xor -d abc.key -i abc.enc -o abc.txt # to decrypt

where:

• abc.txt is the plaintext file,
• abc.key is the single-use pre-shared key,
• abc.enc is the encrypted file.

Hints

• to speed up the key stream generation of the Linux pseudo-random number generator, install haveged:

sudo apt -y install haveged

With a key that is truly random, the result is a one-time pad, which is unbreakable in theory.

Author

• Jakob Flierl - koppi