XOR
===

DESCRIPTION
-----------
A simple command-line XOR encryption/decryption utility written in C. Uses
cyclic key XOR operation for symmetric encryption/decryption.

COMPILATION
-----------
$ gcc -o xor xor.c

USAGE
-----
1. String mode (encrypt/decrypt a string, output may be binary):
   $ ./xor <STRING> <KEY>

2. Stream mode (process stdin with key, output to stdout):
   $ ./xor <KEY>

EXAMPLES
--------
# Encrypt string to binary file, then decrypt back:
$ ./xor "Hello World" "secret" > encrypted.bin
$ cat encrypted.bin | ./xor "secret"
Hello World