AES Encryption and Decryption

This example demonstrates AES encryption and decryption using Deno's built-in SubtleCrypto API.

Define the text to be encrypted

const text = "Hello, Deno 2!";

Convert the text to a Uint8Array using TextEncoder (required for encryption)

const encoder = new TextEncoder();
const data = encoder.encode(text);

Generate an AES-GCM key for encryption and decryption We used AES-GCM in this example as it is a widely used encryption mode, but you can also use modes like AES-CBC or AES-CTR for different use cases.

const key = await crypto.subtle.generateKey(
  {
    name: "AES-GCM",
    length: 256, // 256-bit encryption key for strong security
  },
  true, // The key is extractable for encryption and decryption
  ["encrypt", "decrypt"], // Key usages: encryption and decryption
);

Generate a random initialization vector (IV) for AES-GCM The IV must be unique for each encryption operation but doesn't need to be secret.

const iv = crypto.getRandomValues(new Uint8Array(12)); // 12-byte IV for AES-GCM

Encrypt the text using AES-GCM

const encryptedData = await crypto.subtle.encrypt(
  {
    name: "AES-GCM",
    iv: iv, // Initialization vector must be unique for each encryption
  },
  key, // The generated key
  data, // The text data to encrypt
);

console.log("Encrypted Data:", new Uint8Array(encryptedData)); // Log the encrypted result as a byte array

Decrypt the encrypted data back to plaintext using the same IV and key. The IV and Key used for decryption must the same as used for encryption

const decryptedData = await crypto.subtle.decrypt(
  {
    name: "AES-GCM",
    iv: iv, // Same IV used for encryption
  },
  key, // The same key used for encryption
  encryptedData, // The encrypted data to decrypt
);

Convert the decrypted data back to a string using TextDecoder

const decryptedText = new TextDecoder().decode(decryptedData);
console.log("Decrypted Text:", decryptedText);

Run this example locally using the Deno CLI:

deno run https://docs.deno.com/examples/aes-encryption.ts