webcrypto
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webcrypto

Caution

The experimental module k6/experimental/webcrypto has graduated, and its functionality is now available globally through the crypto object. The k6/experimental/webcrypto is deprecated and will be removed in the near future.

To migrate your scripts, remove the k6/experimental/webcrypto imports and use the crypto object instead.

With this experimental module, you can use the WebCrypto API in your k6 scripts. However, note that this API is not yet fully implemented and some algorithms and features might still be missing.

The Web Crypto API is a JavaScript API for performing cryptographic operations such as encryption, decryption, digital signature generation and verification, and key generation and management. It provides a standard interface to access cryptographic functionality, which can help ensure that cryptographic operations are performed correctly and securely.

API

The module exports a top-level crypto object with the following properties and methods:

Interface/FunctionDescription
getRandomValuesFills the passed TypedArray with cryptographically sound random values.
randomUUIDReturns a randomly generated, 36 character long v4 UUID.
subtleThe SubtleCrypto interface provides access to common cryptographic primitives, such as hashing, signing, encryption, or decryption.

Example

JavaScript 
import { crypto } from 'k6/experimental/webcrypto';

export default async function () {
  const plaintext = stringToArrayBuffer('Hello, World!');

  /**
   * Generate a symmetric key using the AES-CBC algorithm.
   */
  const key = await crypto.subtle.generateKey(
    {
      name: 'AES-CBC',
      length: 256,
    },
    true,
    ['encrypt', 'decrypt']
  );

  /**
   * Encrypt the plaintext using the AES-CBC key with
   * have generated.
   */
  const iv = crypto.getRandomValues(new Uint8Array(16));
  const ciphertext = await crypto.subtle.encrypt(
    {
      name: 'AES-CBC',
      iv: iv,
    },
    key,
    plaintext
  );

  /**
   * Decrypt the ciphertext using the same key to verify
   * that the resulting plaintext is the same as the original.
   */
  const deciphered = await crypto.subtle.decrypt(
    {
      name: 'AES-CBC',
      iv: iv,
    },
    key,
    ciphertext
  );

  console.log(
    'deciphered text == original plaintext: ',
    arrayBufferToHex(deciphered) === arrayBufferToHex(plaintext)
  );
}

function arrayBufferToHex(buffer) {
  return [...new Uint8Array(buffer)].map((x) => x.toString(16).padStart(2, '0')).join('');
}

function stringToArrayBuffer(str) {
  const buf = new ArrayBuffer(str.length * 2); // 2 bytes for each char
  const bufView = new Uint16Array(buf);
  for (let i = 0, strLen = str.length; i < strLen; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}