Encryption and authentication

The encryption logic and salt generation logic, which are used to generate the hashed_password and salt values representing the password value, are defined as UserSchema methods.

mern-skeleton/server/models/user.model.js:

UserSchema.methods = {
  authenticate: function(plainText) {
    return this.encryptPassword(plainText) === this.hashed_password
  },
  encryptPassword: function(password) {
    if (!password) return ''
    try {
      return crypto
        .createHmac('sha1', this.salt)
        .update(password)
        .digest('hex')
    } catch (err) {
      return ''
    }
  },
  makeSalt: function() {
    return Math.round((new Date().valueOf() * Math.random())) + ''
  }
}

Additionally, the authenticate method is also defined as a UserSchema method, which is used when a user supplied password must be authenticated for sign-in.

The crypto module in Node is used to encrypt the user-provided password string into a hashed_password with a randomly generated salt value. The hashed_password and the salt is stored in the user document when the user details are saved to the database on a create or update. Both the hashed_password and salt values are required in order to match and authenticate a password string provided during user sign-in, using the authenticate method defined previously.