Compile-time string obfuscation with runtime decryption and secure memory wiping.

Overview

obfuse provides compile-time string encryption with lazy runtime decryption. Strings are encrypted during compilation and embedded in the binary as ciphertext. They are decrypted only when accessed at runtime.

Security Warning

This is obfuscation, not encryption. The encryption key is embedded in the binary alongside the ciphertext. A determined attacker can extract both.

Appropriate uses:

• Preventing casual inspection of binaries (strings command, hex editors)
• Stopping automated string extraction tools
• Basic protection against unsophisticated reverse engineering

NOT appropriate for:

• Protecting highly sensitive secrets (use proper secrets management)
• Compliance requirements (PCI-DSS, HIPAA, SOC2, etc.)
• Scenarios where key extraction would be catastrophic

Features

Exactly one encryption algorithm must be enabled (mutually exclusive):

• aes-256-gcm (default) - AES-256 in GCM mode (strongest)
• aes-128-gcm - AES-128 in GCM mode
• chacha20-poly1305 - ChaCha20-Poly1305 AEAD
• xor - Simple XOR cipher (fast, weakest)

Usage

Basic Usage

use obfuse::obfuse;

fn main() {
    // String is encrypted at compile time
    let secret = obfuse!("my secret API key");

    // Decrypted only when accessed
    println!("Secret: {}", secret.as_str());

    // Memory is securely wiped when `secret` goes out of scope
}

Deterministic Mode (for Testing/CI)

use obfuse::obfuse;

fn main() {
    // Same seed = same encryption = reproducible builds
    let secret = obfuse!("my secret", seed = "test_seed");
    println!("{}", secret.as_str());
}

Error Handling

use obfuse::{obfuse, ObfuseError};

fn main() {
    let secret = obfuse!("sensitive data");

    match secret.try_as_str() {
        Ok(s) => println!("Secret: {s}"),
        Err(ObfuseError::AllocationFailed) => {
            eprintln!("Out of memory during decryption");
        }
        Err(ObfuseError::AuthenticationFailed) => {
            eprintln!("Decryption failed - binary may be corrupted");
        }
        Err(ObfuseError::InvalidUtf8(e)) => {
            eprintln!("Invalid UTF-8: {e}");
        }
    }
}