---
modificationDate: January 15, 2026
title: Crypto
description: A universal library for crypto operations.
sourceCodeUrl: 'https://github.com/expo/expo/tree/sdk-54/packages/expo-crypto'
packageName: 'expo-crypto'
iconUrl: '/static/images/packages/expo-crypto.png'
platforms: ['android', 'ios', 'tvos', 'web', 'expo-go']
---

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# Expo Crypto

A universal library for crypto operations.
Android, iOS, tvOS, Web, Included in Expo Go

> For the complete documentation index, see [llms.txt](/llms.txt). Use this file to discover all available pages.

`expo-crypto` enables you to hash data in an equivalent manner to the Node.js core `crypto` API.

## Installation

```sh
npx expo install expo-crypto
```

If you are installing this in an [existing React Native app](/bare/overview), make sure to [install `expo`](/bare/installing-expo-modules) in your project.

## Usage

```jsx
import { useEffect } from 'react';
import { StyleSheet, View, Text } from 'react-native';
import * as Crypto from 'expo-crypto';

export default function App() {
  useEffect(() => {
    (async () => {
      const digest = await Crypto.digestStringAsync(
        Crypto.CryptoDigestAlgorithm.SHA256,
        'GitHub stars are neat 🌟'
      );
      console.log('Digest: ', digest);
      /* Some crypto operation... */
    })();
  }, []);

  return (
    <View style={styles.container}>
      <Text>Crypto Module Example</Text>
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
});
```

## API

```js
import * as Crypto from 'expo-crypto';
```

## Methods

### `Crypto.digest(algorithm, data)`

Supported platforms: Android, iOS, tvOS, Web.

| Parameter | Type | Description |
| --- | --- | --- |
| `algorithm` | [CryptoDigestAlgorithm](#cryptodigestalgorithm) | The cryptographic hash function to use to transform a block of data into a fixed-size output. |
| `data` | `BufferSource` | The value that will be used to generate a digest. |

  

The `digest()` method of `Crypto` generates a digest of the supplied `TypedArray` of bytes `data` with the provided digest `algorithm`. A digest is a short fixed-length value derived from some variable-length input. **Cryptographic digests** should exhibit _collision-resistance_, meaning that it's very difficult to generate multiple inputs that have equal digest values. On web, this method can only be called from a secure origin (HTTPS) otherwise, an error will be thrown.

Returns: `Promise<arraybuffer>`

A Promise which fulfills with an ArrayBuffer representing the hashed input.

Example

```ts
const array = new Uint8Array([1, 2, 3, 4, 5]);
const digest = await Crypto.digest(Crypto.CryptoDigestAlgorithm.SHA512, array);
console.log('Your digest: ' + digest);
```

### `Crypto.digestStringAsync(algorithm, data, options)`

Supported platforms: Android, iOS, tvOS, Web.

| Parameter | Type | Description |
| --- | --- | --- |
| `algorithm` | [CryptoDigestAlgorithm](#cryptodigestalgorithm) | The cryptographic hash function to use to transform a block of data into a fixed-size output. |
| `data` | `string` | The value that will be used to generate a digest. |
| `options`(optional) | [CryptoDigestOptions](#cryptodigestoptions) | Format of the digest string. Defaults to: `CryptoDigestOptions.HEX`. |

  

The `digestStringAsync()` method of `Crypto` generates a digest of the supplied `data` string with the provided digest `algorithm`. A digest is a short fixed-length value derived from some variable-length input. **Cryptographic digests** should exhibit _collision-resistance_, meaning that it's very difficult to generate multiple inputs that have equal digest values. You can specify the returned string format as one of `CryptoEncoding`. By default, the resolved value will be formatted as a `HEX` string. On web, this method can only be called from a secure origin (HTTPS) otherwise, an error will be thrown.

Returns: `Promise<digest>`

Return a Promise which fulfills with a value representing the hashed input.

Example

```ts
const digest = await Crypto.digestStringAsync(
  Crypto.CryptoDigestAlgorithm.SHA512,
  '🥓 Easy to Digest! 💙'
);
```

### `Crypto.getRandomBytes(byteCount)`

Supported platforms: Android, iOS, tvOS, Web.

| Parameter | Type | Description |
| --- | --- | --- |
| `byteCount` | `number` | A number within the range from `0` to `1024`. Anything else will throw a `TypeError`. |

  

Generates completely random bytes using native implementations. The `byteCount` property is a `number` indicating the number of bytes to generate in the form of a `Uint8Array`. Falls back to `Math.random` during development to prevent issues with React Native Debugger.

Returns: `Uint8Array`

An array of random bytes with the same length as the `byteCount`.

### `Crypto.getRandomBytesAsync(byteCount)`

Supported platforms: Android, iOS, tvOS, Web.

| Parameter | Type | Description |
| --- | --- | --- |
| `byteCount` | `number` | A number within the range from `0` to `1024`. Anything else will throw a `TypeError`. |

  

Generates completely random bytes using native implementations. The `byteCount` property is a `number` indicating the number of bytes to generate in the form of a `Uint8Array`.

Returns: `Promise<uint8array>`

A promise that fulfills with an array of random bytes with the same length as the `byteCount`.

### `Crypto.getRandomValues(typedArray)`

Supported platforms: Android, iOS, tvOS, Web.

| Parameter | Type | Description |
| --- | --- | --- |
| `typedArray` | `T` | An integer based [`TypedArray`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray) to fill with cryptographically secure random values. It modifies the input array in place. |

  

The `getRandomValues()` method of `Crypto` fills a provided `TypedArray` with cryptographically secure random values.

Returns: `T`

The input array filled with cryptographically secure random values.

Example

```ts
const byteArray = new Uint8Array(16);
Crypto.getRandomValues(byteArray);
console.log('Your lucky bytes: ' + byteArray);
```

### `Crypto.randomUUID()`

Supported platforms: Android, iOS, tvOS, Web.

The `randomUUID()` method returns a unique identifier based on the V4 UUID spec (RFC4122). It uses cryptographically secure random values to generate the UUID.

Returns: `string`

A string containing a newly generated UUIDv4 identifier

Example

```ts
const UUID = Crypto.randomUUID();
console.log('Your UUID: ' + UUID);
```

## Types

### `CryptoDigestOptions`

Supported platforms: Android, iOS, tvOS, Web.

| Property | Type | Description |
| --- | --- | --- |
| encoding | [CryptoEncoding](#cryptoencoding) | Format the digest is returned in. |

### `Digest`

Supported platforms: Android, iOS, tvOS, Web.

Type: `string`

## Enums

### `CryptoDigestAlgorithm`

Supported platforms: Android, iOS, tvOS, Web.

[`Cryptographic hash function`](https://developer.mozilla.org/en-US/docs/Glossary/Cryptographic_hash_function)

#### `MD2`

Supported platforms: iOS.

`CryptoDigestAlgorithm.MD2 = "MD2"`

`128` bits.

#### `MD4`

Supported platforms: iOS.

`CryptoDigestAlgorithm.MD4 = "MD4"`

`128` bits.

#### `MD5`

Supported platforms: Android, iOS.

`CryptoDigestAlgorithm.MD5 = "MD5"`

`128` bits.

#### `SHA1`

`CryptoDigestAlgorithm.SHA1 = "SHA-1"`

`160` bits.

#### `SHA256`

`CryptoDigestAlgorithm.SHA256 = "SHA-256"`

`256` bits. Collision Resistant.

#### `SHA384`

`CryptoDigestAlgorithm.SHA384 = "SHA-384"`

`384` bits. Collision Resistant.

#### `SHA512`

`CryptoDigestAlgorithm.SHA512 = "SHA-512"`

`512` bits. Collision Resistant.

### `CryptoEncoding`

Supported platforms: Android, iOS, tvOS, Web.

#### `BASE64`

`CryptoEncoding.BASE64 = "base64"`

Has trailing padding. Does not wrap lines. Does not have a trailing newline.

#### `HEX`

`CryptoEncoding.HEX = "hex"`

## Error codes

| Code | Description |
| --- | --- |
| `ERR_CRYPTO_UNAVAILABLE` | **Web Only.** Access to the WebCrypto API is restricted to secure origins (localhost/https). |
| `ERR_CRYPTO_DIGEST` | An invalid encoding type provided. |