Geoloqi's Password Encryption Code

password.rb

# Due to recent concerns regarding password safety, Geoloqi has decided to publicly release the code
# that we use to do password hashing. After consulting with the community, this code now uses BCrypt for hashing 
# (http://codahale.com/how-to-safely-store-a-password), which is based on blowfish, uses an integrated
# salting mechanism, and makes brute forcing expensive for attackers. It is widely used in the industry for
# production environments.
#
# Improvement suggestions are always welcome. Geoloqi takes security very seriously, and designs our systems to
# be as security-oriented as practically possible. We also believe in security transparency, because it leads to
# better security than obscurity, and is a more honest interaction with our customers.
#
# "The mantra of any good security engineer is: `Security is not a product, but a process.` It's more than
# designing strong cryptography into a system; it's designing the entire system such that all security 
# measures, including cryptography, work together."
#
# -- Bruce Schneier, author of "Applied Cryptography". 

require 'bcrypt'

module Sequel
  module Password
    def self.included(base)
      base.extend(ClassMethods)

      # Generate methods to login, so that we only have the methods on columns that actually exist for the record.
      base.instance_eval do
        [:username, :email].each do |identifier|
          if columns.include? identifier
            define_singleton_method "valid_#{identifier}_login?".to_sym do |application, value, plaintext|
              valid_login? application, identifier, value, plaintext
            end
          end
        end
      end
    end

    module ClassMethods
      def valid_login?(application, column, value, plaintext)
        user = self[:application => application, column.to_sym => value]
        return false if user.nil?
        user.valid_password? plaintext
      end
    end

    def valid_password?(plaintext)
      BCrypt::Password.new(values[:password_hash]) == plaintext
    end

    def password=(plaintext)
      @password_length = plaintext.length
      values[:password_hash] = BCrypt::Password.create plaintext
    end
  end
end