Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.

JavaScript API

k6/experimental

webcrypto

SubtleCrypto

Open source

SubtleCrypto

The SubtleCrypto interface provides a set of low-level cryptographic primitives such as encryption, decryption, digital signature generation and verification, and key generation and management. It is useful for using secure and efficient cryptographic operations within k6 scripts.

Methods

Method	Description
encrypt	Encrypts the given plaintext data using the specified algorithm and key.
decrypt	Decrypts the given ciphertext data using the specified algorithm and key.
sign	Signs the given data using the specified algorithm and key.
verify	Verifies the signature of the given data using the specified algorithm and key.
digest	Computes the digest (hash) of the given data using the specified algorithm.
generateKey	Generates a new cryptographic key for use with the specified algorithm.
importKey	Imports a raw key material into the Web Crypto API, generating a new key object to use with the specified algorithm.
exportKey	Exports the raw key material of the given key object.

Example

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;
}