WWR - Railsplugin: Acts As Secure

Acts As Secure

Introduction

ActsAsSecure adds an ability to store ActiveRecord model's fields encrypted in a DB. When a model is marked with acts_as_secure, the :binary type fields are recognized as needed to be stored encrypted. The plugin does before_save/after_save/after_find encryption/decryption thus making it transparent for a code using the secure models.

The plugin supports a master key approach as well as individual records encryption keys. It does not contain any crypto provider but allows to plug in any external one as long as it supports encrypt/decrypt methods.

The fields are converted to a YAML form before encryption. After description they are restored via YAML.load. Since fields are stored encrypted, the find usage is very limited.

Usage

=== Master Key Provider Usage

class SecureModel < ActiveRecord::Base acts_as_secure :crypto_provider => MasterKeyProviderClassOrInstance end

SecureModel.create() SecureModel.find(:first)

=== Individual Keys Provider Usage

class SecureModel < ActiveRecord::Base acts_as_secure end

SecureModel.with_crypto_provider(SomeProvider.new(some_param)) { SecureModel.find(:first) } SecureModel.with_crypto_provider(SomeProvider.new(some_param)) { SecureModel.create() }

=== Other Options

acts_as_secure :storage_type => :text —changes the secure storage type from :binary to the supplied one acts_as_secure :except => [:field1, :field2]—disables the secure behavior for the :binary type fields in a supplied list

Example

Let's define three models: Fruit (not secure), SecretFruit (uses the master key approach), and UberSecretFruit (uses the individual key approach).

Rot13CryptoProvider represents a master key provider. SaltedRot13CryptoProvider depends on a salt individual for each record.

= Models

class Fruit < ActiveRecord::Base has_one :secret_fruit has_one :uber_secret_fruit end

class CreateFruits < ActiveRecord::Migration def self.up create_table :fruits do |t| t.column :name, :string end end end

class Rot13CryptoProvider class << self def encrypt(arg) arg.tr(“A-Za-z”, “N-ZA-Mn-za-m”) end alias_method :decrypt, :encrypt end end

class SecretFruit < ActiveRecord::Base acts_as_secure :crypto_provider => Rot13CryptoProvider belongs_to :fruit end

class CreateSecretFruits < ActiveRecord::Migration def self.up create_table :secret_fruits do |t| t.column :name, :binary t.column :fruit_id, :integer end end end

class SaltedRot13CryptoProvider def initialize(salt) @salt = salt end def encrypt(arg) @salt + arg.tr(“A-Za-z”, “N-ZA-Mn-za-m”) end def decrypt(arg) arg[@salt.size .. -1].tr(“A-Za-z”, “N-ZA-Mn-za-m”) end end

class UberSecretFruit < ActiveRecord::Base acts_as_secure belongs_to :fruit end

class CreateUberSecretFruits < ActiveRecord::Migration def self.up create_table :uber_secret_fruits do |t| t.column :name, :binary t.column :fruit_id, :integer end end end

=== Usage

f = Fruit.create(:name => ‘passion fruit’) SecretFruit.create(:name => ‘maracuya’, :fruit => f) puts f.secret_fruit.name maracuya secret = readline.chomp uber_secret crypto_provider = SaltedRot13CryptoProvider.new(secret) UberSecretFruit.with_crypto_provider(crypto_provider) { UberSecretFruit.create(:name => ‘Passiflora edulis’, :fruit => f) } UberSecretFruit.with_crypto_provider(crypto_provider) { puts f.uber_secret_fruit.name } Passiflora edulis

=== DB

select * from secret_fruits; ——-—-—-—-—- | id | name | fruit_id | ——-—-—-—-—- | 1 | - znenphln | 1 | ——-—-—-—-—-

select * from uber_secret_fruits; ——-—-—-—-—-—-—-—-—- | id | name | fruit_id | ——-—-—-—-—-—-—-—-—- | 1 | uber_secret—- Cnffvsyben rqhyvf | 1 | ——-—-—-—-—-—-—-—-—-