Blowfish encryption and decryption of strings

cipher.rb

require 'openssl'
require 'base64'

module Cipher
  def self.encrypt(key, data)
    data += 'A' # Add 'A' suffix to support empty data
    cipher(:encrypt, key, data)
  end

  def self.decrypt(key, text)
    data = cipher(:decrypt, key, text)
    data[0...-1] # Remove the 'A' suffix
  end

  def self.encrypt_base64(key, data)
    blowfish_string = self.encrypt(key, data)
    Base64.encode64(blowfish_string)
  end

  def self.decrypt_base64(key, base64_string)
    blowfish_string = Base64.decode64(base64_string)
    self.decrypt(key, blowfish_string)
  end

  private

  def self.cipher(mode, key, data)
    cipher = OpenSSL::Cipher::Cipher.new('bf-cbc').send(mode)
    cipher.key = Digest::SHA256.digest(key)
    cipher.update(data) << cipher.final
  end
end

cipher_spec.rb

require 'spec_helper'

describe Cipher do
  let(:key) { 'secret key' }

  describe 'blowfish' do
    it 'encodes and decodes empty strings' do
      original = ''
      encrypted = Cipher.encrypt(key, original)
      decrypted = Cipher.decrypt(key, encrypted)
      decrypted.should == original
    end

    it 'encodes and decodes strings' do
      original = 'my string'
      encrypted = Cipher.encrypt(key, original)
      decrypted = Cipher.decrypt(key, encrypted)
      decrypted.should == original
    end
  end


  describe 'base64 and blowfish' do
    it 'encodes and decodes empty strings' do
      original = ''
      encrypted = Cipher.encrypt_base64(key, original)
      decrypted = Cipher.decrypt_base64(key, encrypted)
      decrypted.should == original
    end

    it 'encodes and decodes strings' do
      original = 'my string'
      encrypted = Cipher.encrypt_base64(key, original)
      decrypted = Cipher.decrypt_base64(key, encrypted)
      decrypted.should == original
    end
  end
end

updated spec for newer rspec syntax

require 'spec_helper'

describe Cipher do
  let(:key) { 'secret key' }

  describe 'blowfish' do
    it 'encodes and decodes empty strings' do
      original = ''
      encrypted = Cipher.encrypt(key, original)
      decrypted = Cipher.decrypt(key, encrypted)
      expect(decrypted).to eql(original)
    end

    it 'encodes and decodes strings' do
      original = 'my string'
      encrypted = Cipher.encrypt(key, original)
      decrypted = Cipher.decrypt(key, encrypted)
      expect(decrypted).to eql(original)
    end
  end


  describe 'base64 and blowfish' do
    it 'encodes and decodes empty strings' do
      original = ''
      encrypted = Cipher.encrypt_base64(key, original)
      decrypted = Cipher.decrypt_base64(key, encrypted)
      expect(decrypted).to eql(original)
    end

    it 'encodes and decodes strings' do
      original = 'my string'
      encrypted = Cipher.encrypt_base64(key, original)
      decrypted = Cipher.decrypt_base64(key, encrypted)
      expect(decrypted).to eql(original)
    end
  end
end