@substrate-system/simple-aes

simple AES

Cryptography used by vanishing.page. Works in browsers and node.

This is generally useful as a dead simple way of working with symmetric keys in a browser or node.

Thanks to Fission, the original author for much of this code.

Install
Use
- Bundler
- pre-bundled
API

Install

npm i -S @substrate-system/simple-aes

Use

Bundler

Just import

import {
    decryptMessage,
    encryptMessage,
    type Message
} from '@substrate-system/simple-aes'
// } from '@substtrate-system/simple-aes/compat'  // for older browsers

pre-bundled

This exposes pre-bundled & minified JS files.

copy

cp ./node_modules/@substrate-system/simple-aes/dist/compat.min.js ./public
cp ./node_modules/@substrate-system/simple-aes/dist/index.min.js ./public/simple-aes.min.js

link

<body>
    <!-- ... -->

    <script type="module" src="./compat.min.js"></script>
    <!-- or webcrypto version -->
    <script type="module" src="./simple-aes.min.js"></script>
</body>

API

`@substrate-system/simple-aes`

Use the webcrypto API.

import {
    decryptMessage,
    encryptMessage,
    type Message
} from '@substrate-system/simple-aes'

`@substrate-system/simple-aes/compat`

Use a user-land module, @noble/ciphers. This will work in browsers of all ages.

import {
    encryptMessage,
    decryptMessage
} from '@substrate-system/simple-aes/compat'

`encryptMessage`

Generate a new AES key and encrypt the given message object. Return an array of [ encryptedMessage, { key }], where key is a new AES key, encoded as base64url.

Can pass in a size for the key. By default it uses 256 bits.

async function encryptMessage (
    msg:{ content:string },
    opts:{ length:SymmKeyLength } = { length: DEFAULT_SYMM_LEN }
):Promise<[{ content:string }, { key:string }]>

encrypt example

import { SymmKeyLength, encryptMessage } from '@substrate-system/simple-aes'

const [encryptedMsg, { key }] = await encryptMessage({
    content: 'hello world'
})

// or pass in a key size
await encryptMessage({
    content: 'hello'
}, {
    length: SymmKeyLength.B128
})

console.log(encryptedMessage)
// =>  { content: '5eAcA6+jnBfbuCx8L...' }

`decryptMessage`

Decrypt the given message with the given key. Suitable for decrypting a message that was encrypted by this library. Key is an AES key, base64url encoded.

async function decryptMessage (
    msg:{ content:string },
    keyString:string  // <-- base64url
):Promise<{ content:string }>

decrypt example

import { test } from '@substrate-system/tapzero'
import { decryptMessage } from '@substrate-system/simple-aes'

test('decrypt the message', async t => {
    const decrypted = await decryptMessage(message, key)
    t.equal(decrypted.content, 'hello world',
        'should decrypt to the right text')
})