SubtleCrypto

`crypto.subtle.encrypt`

Encrypts data using the specified algorithm and cryptographic key

Syntax

JavaScript

crypto.subtle.encrypt(algorithm, key, data)

Parameters

Parameter	Type	Description
algorithm	AlgorithmIdentifier	The encryption algorithm and parameters
key	CryptoKey	The key to use for encryption
data	ArrayBuffer \| TypedArray \| DataView	The data to encrypt

Return Value

A Promise that resolves to an ArrayBuffer containing the ciphertext

Examples

Basic Usage

const key = await crypto.subtle.generateKey(
  { name: 'AES-GCM', length: 256 },
  true,
  ['encrypt', 'decrypt']
)
const iv = crypto.getRandomValues(new Uint8Array(12))
const encoded = new TextEncoder().encode('Secret message')
const encrypted = await crypto.subtle.encrypt(
  { name: 'AES-GCM', iv },
  key,
  encoded
)

Practical Example

async function encryptText(text: string, key: CryptoKey) {
  const iv = crypto.getRandomValues(new Uint8Array(12))
  const data = new TextEncoder().encode(text)
  const cipher = await crypto.subtle.encrypt({ name: 'AES-GCM', iv }, key, data)
  return { iv, cipher }
}

Advanced Usage

async function generateAndExportKey() {
  const key = await crypto.subtle.generateKey(
    { name: 'AES-GCM', length: 256 },
    true,
    ['encrypt', 'decrypt']
  )
  const exported = await crypto.subtle.exportKey('jwk', key)
  console.log(exported)
}

Understanding crypto.subtle.encrypt

The crypto.subtle.encrypt method in JavaScript encrypts data using the specified algorithm and cryptographic key. It belongs to the SubtleCrypto object and is one of the most widely used methods for working with subtlecrypto values in modern JavaScript and TypeScript applications.

The method signature is crypto.subtle.encrypt(algorithm, key, data). It accepts 3 parameters: algorithm, key, data. When called, it returns a promise that resolves to an arraybuffer containing the ciphertext. Understanding when and how to use encrypt() helps you write more expressive, readable code.

Common use cases for crypto.subtle.encrypt include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like crypto-subtle-decrypt, crypto-subtle-digest, crypto-getrandomvalues, enabling you to chain operations together for complex data manipulation pipelines.

Supported in all modern browsers. Requires a secure context (HTTPS).