browser-crypto

A safe Rust interface to browser-based cryptographic operations using the Web Crypto API.

This crate provides a type-safe wrapper around the browser's native cryptographic functionality, making it easier to perform common cryptographic operations in WebAssembly applications.

Features

• Type-safe cryptographic algorithm implementations
• Secure nonce generation and handling
• AES-256-GCM encryption and decryption
• Proper error handling and conversion from Web API exceptions
• WebAssembly-first design
• Zero-copy operations where possible

Usage

Add this to your Cargo.toml:

[dependencies]
browser-crypto = "0.1.0"

Basic Example

use browser_crypto::aes256gcm::Aes256Gcm;
use browser_crypto::algorithm::Algorithm;

async fn encrypt_data() -> Result<(), Box<dyn std::error::Error>> {
    // Create a new AES-256-GCM instance with a key
    let key_bytes = [0u8; 32]; // Replace with your secure key
    let cipher = Aes256Gcm::from_key(&key_bytes).await?;

    // Generate a random nonce
    let nonce = Aes256Gcm::generate_nonce()?;

    // Encrypt some data
    let data = b"Secret message";
    let encrypted = cipher.encrypt(&nonce, data).await?;

    // Decrypt the data
    let decrypted = cipher.decrypt(&nonce, &encrypted).await?;
    assert_eq!(data.to_vec(), decrypted);

    Ok(())
}

Security Considerations

This crate relies on the browser's implementation of the Web Crypto API, which:

• Uses the platform's secure random number generator
• Implements cryptographic operations in native code
• Provides protection against timing attacks
• Follows modern cryptographic standards

However, users should be aware that:

• Keys should be generated and stored securely
• Nonces should never be reused with the same key
• The security of the application depends on the security of the browser

Feature Flags

• log-error: Enables console logging of unknown errors (useful for debugging)

Browser Compatibility

This crate requires a browser with support for:

• Web Crypto API
• WebAssembly
• Async/await

Most modern browsers (Chrome, Firefox, Safari, Edge) support these features.

Error Handling

The crate provides detailed error types that map directly to Web Crypto API exceptions:

• Error: General Web Crypto API errors
• EncryptionError: Encryption-specific errors
• DecryptionError: Decryption-specific errors
• NonceError: Nonce generation and validation errors
• ImportKeyError: Key import and format errors

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under MIT.

Acknowledgments

• Built on top of the Web Crypto API
• Uses wasm-bindgen for WebAssembly integration