Zenc - Zig Secure File Encryption

This project encrypts files to ensure both their privacy and integrity. The process follows a series of best practices to achieve strong security.

Security and Algorithms

For a security-focused tool, transparency regarding the cryptographic methods is critical for trust and verification.

Zenc follows current cryptographic best practices:

Feature	Details
Algorithm	AES-256 in Galois/Counter Mode (GCM), providing both confidentiality (secrecy) and authenticated encryption.
Integrity	Ensured by the GCM Message Authentication Code (GCM-MAC), which verifies the integrity and authenticity of the ciphertext to detect any unauthorized modifications or corruption.
Key Derivation	The symmetric key is derived from a user-supplied passphrase using a robust Key Derivation Function (KDF) to protect against brute-force attacks. The tool will prompt for the passphrase via standard input.
File Naming	Encryption adds the .ezenc extension. Decryption replaces the .ezenc extension (if available) w/ .dzenc.

Usage

NOTE: Zenc always captures paths relative from the cwd (unless an absolute path is provided).

Encrypting or Decrypting a file creates a file in the same directory as captured from but w/ ezenc (encryption) or dzenc (decryption) concatenated to the end.

CLI Options

• -h OR --help -> Prints this help menu
• -e=<file_to_encrypt> -> Encrypt file.
• -d=<file_to_decrypt> -> Decrypt file.
• --dont_check_enc -> Stop immediate encrypted file decryption check (increase speed).
• --version OR version -> Prints build versioning information.
• -v OR --verbose -> Prints extra stdout information.

Examples

1. Encrypt secret.txt

.\zenc -e=secret.txt

Creates secret.txt.ezenc

2. Decrypt the file

.\zenc -d=secret.txt.ezenc

Creates secret.txt.dzenc

3. Encrypt (Verbose)

.\zenc -e=secret.txt -v

Encrypts and prints details about the process to stdout.

Building the Project

Installation

To build the optimised release executable:

zig build -Doptimize=ReleaseSafe

The executable is built to the default location:

zenc/zig-out/bin/zenc

Zig Version

0.15.1

Debugging

To launch the executable and run an encryption command within the LLDB debugger:

lldb .\zig-out\bin\zenc.exe -- -e="./test/file1.txt"