secret-local-storage

A wrapper around 'localStorage/sessionStorage' to provide storage encryption with libsodium

Installation

$ npm install secret-local-storage

Usage

const { keygen } = require('secret-local-storage/keygen')
const secretKey = keygen()
const secretStorage = require('secret-local-storage')(secretKey) // will generate key by default

secretStorage.setItem('someKey', 'some secret value')
console.log(secretStorage.getItem('someKey')) // some secret value
console.log(localStorage.getItem('someKey')) // 5J3nmcMCcABSwJN

Example

const secretStorage = require('secret-local-storage')('3e852b5d881b22261b8e417e217a9fa9757f4532305c4e46e2a6966aa89840f6')

localStorage.setItem('hello', 'world')
console.log(secretStorage.getItem('hello')); // outputs 'hello'

secretStorage.setItem('hello', 'world')
console.log(localStorage.getItem('hello')); // should be encrypted

API

The SecretLocalStorage class implements the same API as the Storage API.

const secretStorage = require('secret-local-storage')(secretKey, opts)

Create a secret storage instance with an optional secret key and options where:

• secretKey is a 32-byte buffer or 64 character 'hex' encoded string. The encoding of the secret key can be specified with opts.secretKeyEncoding. If you do not supply a secret key, then one will be generated for you. This should be saved and re-used to read the encrypted values.

• opts is an optional object to configure the storage where:

  • opts.secretKeyEncoding is the encoding of the secret key
  • opts.valueEncoding is an object containing encode(value) and decode(buffer) functions.
  • opts.storage can be Storage interface or a function that returns one.
  • opts.seed is an optionl seed value to generate the secret key that should be 32 bytes

secretKey.secretKey

A 32 byte secret key used for encryption and child key derivation.

secretStorage.storage

The Storage interface backing the SecretLocalStorage instance.

secretKey.valueEncoding

The value encoding used for encoding and ecoding value written to storage.

secretKey.valueEncoding.encode(value)

Encodes value into a Buffer

secretKey.valueEncoding.decode(buffer)

Decodes buffer into a value. Most likely, a string.

secretStorage.key(n)

The same API as Storage.key().

secretStorage.getItem(key)

The same API as Storage.getItem(). If decryption fails, this function will return the original value found in storage.

secretStorage.setItem(key)

The same API as Storage.setItem().

secretStorage.removeItem(key)

The same API as Storage.removeItem().

secretStorage.clear(key)

The same API as Storage.clear().

License

MIT