Window: crypto 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.

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.

JavaScript

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

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

HTML

html
<p id="myRandText">The random numbers are:</p>
<button type="button" onClick="genRandomNumbers()">
  Generate 10 random numbers
</button>

Result

Specifications

Specification
Web Cryptography Level 2
# dom-windoworworkerglobalscope-crypto

Browser compatibility

See also