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 | ----———————————–----------

Installation

As plugin: script/plugin install svn://rubyforge.org/var/svn/acts-as-secure/trunk/vendor/plugins/acts_as_secure

License

ActsAsSecure released under the MIT license.

Support

The plugin RubyForge page is rubyforge.org/projects/acts-as-secure