ChaChaPoly is a combination of the ChaCha20 stream cipher and the Poly1305 message authentication code. This cryptographic suite is known for its performance and security, making it a popular choice in various applications, including secure communications. In Apple environments, particularly iOS and macOS, you can leverage the built-in cryptographic libraries to implement ChaChaPoly encryption.

Examples:

Using Swift and Apple's CryptoKit

Apple's CryptoKit provides a straightforward way to use ChaChaPoly encryption. Below is an example of how you can encrypt and decrypt data using ChaChaPoly in a Swift application.

import CryptoKit
import Foundation

// Sample data to encrypt
let message = "Hello, ChaChaPoly!"
let dataToEncrypt = message.data(using: .utf8)!

// Generate a random symmetric key
let key = SymmetricKey(size: .bits256)

// Encrypt the data
let sealedBox = try! ChaChaPoly.seal(dataToEncrypt, using: key)

// Extract the nonce, ciphertext, and tag
let nonce = sealedBox.nonce
let ciphertext = sealedBox.ciphertext
let tag = sealedBox.tag

print("Nonce: \(nonce)")
print("Ciphertext: \(ciphertext)")
print("

// Decrypt the data
let sealedBoxToOpen = try! ChaChaPoly.SealedBox(nonce: nonce, ciphertext: ciphertext, tag: tag)
let decryptedData = try! ChaChaPoly.open(sealedBoxToOpen, using: key)

// Convert decrypted data back to a string
let decryptedMessage = String(data: decryptedData, encoding: .utf8)!
print("Decrypted Message: \(decryptedMessage)")

This example demonstrates how to encrypt and decrypt a simple message using ChaChaPoly in a Swift application. It utilizes Apple's CryptoKit, which is available in iOS 13 and macOS 10.15 or later.

Command Line Example

While there isn't a direct command-line tool in macOS for ChaChaPoly, you can use OpenSSL, which supports ChaCha20 and Poly1305 separately. However, combining them as ChaChaPoly requires additional scripting.

First, ensure you have OpenSSL installed. You can use Homebrew to install it:

brew install openssl

Here's a basic example of encrypting and decrypting using OpenSSL commands:

# Encrypt using ChaCha20
echo "Hello, ChaChaPoly!" | openssl enc -chacha20 -k secretkey -out encrypted.bin

# Decrypt using ChaCha20
openssl enc -d -chacha20 -k secretkey -in encrypted.bin

Note: This example uses only ChaCha20 for simplicity. For complete ChaChaPoly functionality, you would need to implement additional logic to handle Poly1305 manually.