@livingdocsIO/secure-password

Making Password storage safer for all

Features

• State of the art password hashing algorithm (Argon2id)
• Safe defaults for most applications
• Future-proof so work factors and hashing algorithms can be easily upgraded

Usage

const securePassword = require('secure-password')

// Initialise our password policy
const pwd = securePassword()

const userPassword = Buffer.from('my secret password')

async function run () {
  // Register user
  const hash = await pwd.hash(userPassword)

  // Save hash somewhere
  const result = await pwd.verify(userPassword, hash)

  switch (result) {
    case securePassword.INVALID_UNRECOGNIZED_HASH:
      return console.error('This hash was not made with secure-password. Attempt legacy algorithm')
    case securePassword.INVALID:
      return console.log('Invalid password')
    case securePassword.VALID:
      return console.log('Authenticated')
    case securePassword.VALID_NEEDS_REHASH:
      console.log('Yay you made it, wait for us to improve your safety')

      try {
        const improvedHash = await pwd.hash(userPassword)
        // Save improvedHash somewhere
      } catch (err)
        console.error('You are authenticated, but we could not improve your safety this time around')
      }
      break
  }
}

run()

API

const pwd = new SecurePassword(opts)

Make a new instance of SecurePassword which will contain your settings. You can view this as a password policy for your application. opts takes the following keys:

// Initialise our password policy (these are the defaults)
const pwd = securePassword({
  memoryCost: securePassword.defaults.memoryCost,
  timeCost: securePassword.defaults.timeCost
})

They're both constrained by the constants SecurePassword.limits.memoryCost.min - SecurePassword.limits.memoryCost.max and SecurePassword.limits.timeCost.min - SecurePassword.limits.timeCost.max. If not provided they will be given the default values SecurePassword.defaults.memoryCost and SecurePassword.defaults.timeCost which should be fast enough for a general purpose web server without your users noticing too much of a load time. However your should set these as high as possible to make any kind of cracking as costly as possible. A load time of 1s seems reasonable for login, so test various settings in your production environment.

The settings can be easily increased at a later time as hardware most likely improves (Moore's law) and adversaries therefore get more powerful. If a hash is attempted verified with weaker parameters than your current settings, you get a special return code signalling that you need to rehash the plaintext password according to the updated policy. In contrast to other modules, this module will not increase these settings automatically as this can have ill effects on services that are not carefully monitored.

const hash = await pwd.hash(password)

Takes Buffer password and hashes it. The hashing is done on the same thread as the event loop, therefore normal execution and I/O will be blocked. The function may throw a potential error, but most likely return the Buffer hash.

password must be a Buffer of length SecurePassword.defaults.passwordLength.min - SecurePassword.defaults.passwordLength.max.
hash will be a Buffer any length based on the config parameters.

const symbol = await pwd.verify(password, hash)

Takes Buffer password and hashes it and then safely compares it to the Buffer hash. The hashing is done by a seperate worker as to not block the event loop, so normal execution and I/O can continue. The promise is rejected with potential error, or resolved with one of the symbols SecurePassword.INVALID, SecurePassword.VALID, SecurePassword.VALID_NEEDS_REHASH or SecurePassword.INVALID_UNRECOGNIZED_HASH. Check with strict equality for one the cases as in the example above.

If enum === SecurePassword.VALID_NEEDS_REHASH you should call pwd.hash with password and save the new hash for next time. Be careful not to introduce a bug where a user trying to login multiple times, successfully, in quick succession makes your server do unnecessary work.

password must be a Buffer of length SecurePassword.defaults.passwordLength.min - SecurePassword.defaults.passwordLength.max.
hash will be a Buffer any length based on the config parameters.

SecurePassword.VALID

The password was verified and is valid

SecurePassword.INVALID

The password was invalid

SecurePassword.VALID_NEEDS_REHASH

The password was verified and is valid, but needs to be rehashed with new parameters

SecurePassword.INVALID_UNRECOGNIZED_HASH

The hash was unrecognized and therefore could not be verified. As an implementation detail it is currently very cheap to attempt verifying unrecognized hashes, since this only requires some lightweight pattern matching.

SecurePassword.defaults

{
  hashLength: 32,
  saltLength: 16,
  timeCost: 3,
  memoryCost: 65536,
  parallelism: 1,
  type: 2,
  version: 19
}

SecurePassword.limits

{
  hashLength: { max: 4294967295, min: 4 },
  memoryCost: { max: 4294967295, min: 2048 },
  timeCost: { max: 4294967295, min: 2 },
  parallelism: { max: 16777215, min: 1 },
  passwordLength: { min: 0, max: 4294967295 }
}

Install

npm install @livingdocsIO/secure-password

Credits

Thanks to [Emil Bay] for maintaing https://github.com/emilbayes/secure-password, which this work is built on.

License

ISC