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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.

Open source

AesGcmParams

The AesGcmParams object represents the object that should be passed as the algorithm parameter into the encrypt and decrypt operation when using the AES-GCM algorithm.

For more details, head to the MDN Web Crypto API documentation on AES-GCM.

Properties

PropertyTypeDescription
namestringShould be set to AES-GCM.
ivArrayBuffer, TypedArray, or DataViewThe initialization vector. It must be 12 bytes long, unpredictable and cryptographically random. It must be unique for every encryption operation carried out with a given key. Never reuse an iv with the same key. Yet, it doesn’t need to be secret and can be transmitted along with the ciphertext.
additionalData (optional)ArrayBuffer, TypedArray or DataViewAdditional data that should be authenticated, but not encrypted. It must be included in the calculation of the authentication tag, but not encrypted itself.
tagLength (optional)numberThe length of the authentication tag in bits. Should be set, and will default to 96.

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-GCM',
      length: 256,
    },
    true,
    ['encrypt', 'decrypt']
  );

  /**
   * Encrypt the plaintext using the AES-CBC key with
   * have generated.
   */
  const ciphertext = await crypto.subtle.encrypt(
    {
      name: 'AES-GCM',
      iv: crypto.getRandomValues(new Uint8Array(12)),
    },
    key,
    plaintext
  );
}

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;
}