otpus/test/encryptMessage.js

General purpose cipher for Node & browser

import assert from 'assert/strict'
import { RAND, encryptMessage, decryptMessage } from '../src/index.js'

describe('encryptMessage', function () {
  describe('accept string data. ', function () {
    const strKey = 'string key'

    it('should throw error for binary data.', function () {
      assert.throws(
        () => encryptMessage(Buffer.from('use raw string data'), strKey),
        new TypeError('msg: Use string message.')
      )
    })
  })

  describe('accept string key. ', function () {
    const strData = 'string data'
    const strKey = 'string key'
    it('success enc. dec.', function () {
      const result = decryptMessage(encryptMessage(strData, strKey), strKey)
      assert.ok(result === strData)
    })
  })
  describe('accept any size of buffer key', function () {
    it('success enc. dec.', function () {
      const strData = 'string data'
      const randSizeKey = RAND(RAND(1)[0])
      prn('random keySize', randSizeKey.byteLength)
      const result = decryptMessage(encryptMessage(strData, randSizeKey), randSizeKey)
      assert.ok(result === strData)
    })
  })

  describe('when normal.', function () {
    it('decryptMessage should return same.', function () {
      const key = RAND(32)
      const plainStr = 'this is plain text.'
      const encBase64 = encryptMessage(plainStr, key)
      const dec = decryptMessage(encBase64, key)

      prn('plainStr', plainStr)
      prn('dec', dec)
      assert.equal(plainStr, dec)
    })
  })

  describe('decryptMessage', function () {
    describe('when data is modified', function () {
      it('should return undefined. because dismatch HMAC.', function () {
        const key = RAND(32)
        const plainStr = 'this is plain text.'
        const encBase64 = encryptMessage(plainStr, key)
        // modify encData
        const cropData = Buffer.from(encBase64, 'base64')
        cropData[10] ^= 0x01 // 1bit change.
        const cropBase64 = cropData.toString('base64')
        const dec = decryptMessage(cropBase64, key)
        prn('crop data dec', dec)
        assert.ok(dec === undefined)
      })
    })
  })
})

function prn(tag, v) {
  console.log(tag, v)
}
function prnObj(tag, v) {
  v = JSON.stringify(v, null, 2)
  console.log(tag, v)
}

function hex(title, data) {
  console.log(title, MBP.hex(data))
}