decrypt
The decrypt()
method decrypts some encrypted data.
Usage
decrypt(algorithm, key, data)
Parameters
Name | Type | Description |
---|---|---|
algorithm | AesCbcParams, AesCtrParams, or AesGcmParams object | Defines the algorithm to use and any extra-parameters. The values given for the extra parameters must match those used in the corresponding [encrypt] call. |
key | CryptoKey | The key to use for decryption. |
data | ArrayBuffer , TypedArray , or DataView | The encrypted data to be decrypted (also known as ciphertext). |
Supported algorithms
AES-CBC | AES-CTR | AES-GCM | RSA-OAEP |
---|---|---|---|
✅ AesCbcParams | ✅ AesCtrParams | ✅ AesGcmParams | ❌ |
Return Value
A Promise
that resolves to a new ArrayBuffer
containing the decrypted data.
Throws
Type | Description |
---|---|
InvalidAccessError | Raised 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. |
OperationError | Raised 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
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;
}