CryptoKey: usages property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is available in Web 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

js
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",
  ]);
}

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

Specifications

Specification
Web Cryptography API
# dom-cryptokey-usages

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
usages

Legend

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Full support
Full support