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The RandomSource.getRandomValues() method lets you get cryptographically strong random values. The array given as the parameter is filled with random numbers (random in its cryptographic meaning).

To guarantee enough performance, implementations are not using a truly random number generator, but they are using a pseudo-random number generator seeded with a value with enough entropy. The PRNG used differs from one implementation to the other but is suitable for cryptographic usages. Implementations are also required to use a seed with enough entropy, like a system-level entropy source.

Syntax

cryptoObj.getRandomValues(typedArray);

Parameters

typedArray
Is an integer-based TypedArray, that is an Int8Array, a Uint8Array, an Int16Array, a Uint16Array, an Int32Array, or a Uint32Array. All elements in the array are going to be overridden with random numbers.

Exceptions

Example

/* assuming that window.crypto.getRandomValues is available */

var array = new Uint32Array(10);
window.crypto.getRandomValues(array);

console.log("Your lucky numbers:");
for (var i = 0; i < array.length; i++) {
    console.log(array[i]);
}

Specification

Specification Status Comment
Web Cryptography API Recommendation Initial definition

Browser Compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support 11.0 (Yes) 21.0 11.0 15.0 3.1
Feature Android Chrome for Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support 4.4 23.0 (Yes) 21.0 11.0 37 6.1

See also

Document Tags and Contributors

 Last updated by: herrniemand,