CryptoKey: usages property

Secure contextAvailable in workers

The read-only usages property of the CryptoKey interface indicates what can be done with the key.

Value

An Array of strings from the following list:

• "encrypt": The key may be used to encrypt messages.
• "decrypt": The key may be used to decrypt messages.
• "sign": The key may be used to sign messages.
• "verify": The key may be used to verify signatures.
• "deriveKey": The key may be used in deriving a new key.
• "deriveBits": The key may be used in deriving bits.
• "wrapKey": The key may be used to wrap a key.
• "unwrapKey": The key may be used to unwrap a key.

Examples

const rawKey = window.crypto.getRandomValues(new Uint8Array(16));

// Import an AES secret key from an ArrayBuffer containing the raw bytes.
// Takes an ArrayBuffer string containing the bytes, and returns a Promise
// that will resolve to a CryptoKey representing the secret key.
function importSecretKey(rawKey) {
  return window.crypto.subtle.importKey("raw", rawKey, "AES-GCM", true, [
    "encrypt",
    "decrypt",
  ]);
}

importSecretKey(rawKey).then((key) =>
  console.log(
    `The following usages are reported for this key: ${key.usages.toString()}`,
  ),
);

Specifications

Browser compatibility