Simple, secure tokens for authentication, access keys, sessions etc.

Below is an example using secure-token stored in cookies. Note that you use secureToken.hash to store and verify a token:

var secureToken = require('secure-token')
var db = new Map() // Use map as database for simplicity
function login (req, res) {
  // Do authentication
  // ...
  // If success issue a session token
  var sessionToken = secureToken.create()
  // Here we use the 'session'
  db.set(secureToken.hash(sessionToken, 'session'), true)
  res.writeHead(204, {
    'Set-Cookie': [
      `sessionToken=${secureToken.toString('base64')}`,
      'HttpOnly',
      'Secure'
    ].join(';')
  })
  res.end()
}
function secretPage (req, res) {
  // Get req.sessionToken somehow
  var sessionToken = Buffer.from(req.sessionToken, 'base64')
  var hash = secureToken.hash(sessionToken, 'session')
  if (!db.get(hash)) {
    res.writeHead(400)
    return res.end()
  }
  res.writeHead(200)
  return res.end('Yay!')
}

Create a new token from your OS Cryptographically Secure Pseudorandom Number Generator (CSPRNG), making the token unpredictable and return as a Buffer. size defaults to 18, giving a security level of more than 128 bits, while avoiding any padding when Base 64 encoded.

Hash a token for long-term storage, taking Buffer tokenBuf and an optional namespace which can be either a string or Buffer. You can use namespace to partition your tokens for different use-cases, invalidating tokens which are used for the wrong purpose, while keeping the information hidden in storage. namespace does not add any significant security and is simply so that different tokens are not used in the wrong context.

tokenBuf should be a token generated by secureToken.create and namespace can be a Buffer or String.

The reason it is important to obscure the token is that it is password equivalent, meaning having access to a valid token is the same as having gone through an authentication process, eg. typing a password. You do not want anyone with access to your tokens to be able to impersonate a user.

Using the default token size it should take well over 2^64 guesses to find two tokens that yield the same hash value due to the birthday paradox.

npm install secure-token

ISC