Crypto Library and CLI

A simple C cryptography library and command-line tool for encrypting and decrypting data using a custom stream cipher.

Features

• Shared C library (libcrypt.so) with a simple stream cipher API
• Command-line tool (crypt) for file and stream encryption/decryption
• Unit tests (Unity framework)
• Integration tests for CLI

Build

Requires GCC and GNU Make.

make all        # Build library and CLI
make test       # Run unit tests
make check      # Run unit and CLI integration tests
make clean      # Remove build artifacts

To build with debug symbols:

make clean
make DEBUG=1 all

Usage

CLI

Encrypt a file:

./crypt -k 001122334455 -o encrypted.bin input.txt

Decrypt a file:

./crypt -k 001122334455 encrypted.bin > decrypted.txt

Use a key file:

echo -n -e '\x01\x02\x03\x04\x05\x06' > keyfile
./crypt -f keyfile input.txt > encrypted.bin
./crypt -f keyfile encrypted.bin > decrypted.txt

Use as a filter:

echo "hello world" | ./crypt -k 001122334455 | ./crypt -k 001122334455

Library

See lib/include/crypt.h for API documentation.

Testing

Run all tests:

make check

• Unit tests: make test (runs with Unity)
• CLI integration tests: bash ./test_cli.sh

Project Structure

• lib/ - Library source and headers
• cli/ - Command-line tool source
• test/ - Unit tests
• test_cli.sh - CLI integration test script
• Makefile - Build and test automation