Window: crypto property

The crypto read-only property of the Window interface returns the Crypto object for this window's scope. This object gives web pages access to certain cryptographic related services.

Although the property itself is read-only, all of its methods (and the methods of its child object, SubtleCrypto) are not read-only, and therefore vulnerable to attack by polyfill.

Although crypto is available on all windows, the returned Crypto object only has one usable feature in insecure contexts: the getRandomValues() method. In general, you should use this API only in secure contexts.

Value

An instance of the Crypto interface, providing access to general-purpose cryptography and a strong random-number generator.

Examples

This example uses the crypto property to access the getRandomValues() method.

HTML

<p id="myRandText">The random numbers are:</p>
<button type="button">Generate 10 random numbers</button>

JavaScript

function genRandomNumbers() {
  const array = new Uint32Array(10);
  globalThis.crypto.getRandomValues(array);

  const randText = document.getElementById("myRandText");
  randText.textContent = `The random numbers are: ${array.join(" ")}`;
}

document.querySelector("button").addEventListener("click", genRandomNumbers);

Result

Specifications

Browser compatibility

See also

• The Crypto interface
• WorkerGlobalScope.crypto