decrypt
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Open source

decrypt

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.

The decrypt() method decrypts some encrypted data.

Usage

decrypt(algorithm, key, data)

Parameters

NameTypeDescription
algorithmAesCbcParams, AesCtrParams, or AesGcmParams objectDefines the algorithm to use and any extra-parameters. The values given for the extra parameters must match those used in the corresponding [encrypt] call.
keyCryptoKeyThe key to use for decryption.
dataArrayBuffer, TypedArray, or DataViewThe encrypted data to be decrypted (also known as ciphertext).

Supported algorithms

AES-CBCAES-CTRAES-GCMRSA-OAEP
✅ AesCbcParams✅ AesCtrParams✅ AesGcmParams✅ RsaOaepParams

Return Value

A Promise that resolves to a new ArrayBuffer containing the decrypted data.

Throws

TypeDescription
InvalidAccessErrorRaised when the requested operation is not valid with the provided key. For instance when an invalid encryption algorithm is used, or a key not matching the selected algorithm is provided.
OperationErrorRaised when the operation failed for an operation-specific reason. For instance, if the algorithm size is invalid, or errors occurred during the process of decrypting the ciphertext.

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;
}