envelope-encryptor

Envelope encryption with configurable KEK (Key Encryption Key) provider.

Installation

npm install @autotelic/envelope-encryptor

Usage

AWS KMS

Using AWS KMS

import { createEnvelopeEncryptor, awsKms } from '@autotelic/envelope-encryptor'

const {
  AWS_REGION,
  KMS_KEY_ID,
  KMS_ACCESS_KEY_ID,
  KMS_SECRET_ACCESS_KEY
} = process.env

const keyService = awsKms(KMS_KEY_ID, {
  region: AWS_REGION,
  credentials: {
    accessKeyId: KMS_ACCESS_KEY_ID,
    secretAccessKey: KMS_SECRET_ACCESS_KEY
  }
})

const encryptor = createEnvelopeEncryptor(keyService)

const { encrypt, decrypt } = encryptor

const {
  ciphertext,
  key,
  salt
 } = await encrypt('plaintext')

const plaintext = await decrypt({
  ciphertext: ciphertext.toString(),
  key,
  salt
})

KEK from an env variable

If your KEK will be e.g. stored in a secrets manager you can pass it as a base64 encoded string. The key length must be 32 bytes, you can generate a suitable one like this: crypto.randomBytes(32).toString('base64')

import { createEnvelopeEncryptor, kekService } from '@autotelic/envelope-encryptor'

const keyService = kekService(process.env.KEY_ENCRYPTION_KEY)

const { encrypt, decrypt } = createEnvelopeEncryptor(keyService)

const {
  ciphertext,
  key,
  salt
} = await encrypt('plaintext')

const plaintext = await decrypt({
  ciphertext: ciphertext.toString(),
  key,
  salt
})

In development and testing

If you don't really need to use an actual KEK, e.g. in development or for testing, but you do need to generate DEKs (Data Encryption Key) to work with, there is a dummy KMS service. The "encrypted" key is just a base64 representation of a random buffer. This should definitely not be used in production!

import { createEnvelopeEncryptor, dummyKms } from '@autotelic/envelope-encryptor'

const keyService = dummyKms()

const { encrypt, decrypt } = createEnvelopeEncryptor(keyService)

const {
  ciphertext,
  key,
  salt
} = await encrypt('plaintext')

const plaintext = await decrypt({
  ciphertext: ciphertext.toString(),
  key,
  salt
})

Custom Key Service

You can implement a custom key service to pass to createEnvelopeEncryptor. It should be an object that provides two async functions, getDataKey and decryptDataKey.

getDataKey accepts no arguments and should return a an object containing the encrypted data encryption key (which has been encrypted by the KEK), and the plaintext data encryption key.

decryptDataKey accepts an encrypted data key and should return the plaintext data encryption key.

See the key service implementations in this module for examples.