Module: Sym

Defined in:

lib/sym/crypt.rb,
lib/sym/data.rb,
lib/sym/configurable.rb,
lib/sym/crypt/errors.rb,
lib/sym/data/decoder.rb,
lib/sym/data/encoder.rb,
lib/sym/crypt/version.rb,
lib/sym/crypt/configuration.rb,
lib/sym/data/wrapper_struct.rb,
lib/sym/crypt/cipher_handler.rb,
lib/sym/crypt/extensions/class_methods.rb,
lib/sym/crypt/extensions/instance_methods.rb

Overview

Using Sym Library

This library is a “wrapper” that allows you to take advantage of the symmetric encryption functionality provided by the OpenSSL gem (and the underlying C library). In order to use the library in your ruby classes, you should include the module Sym.

The including class is decorated with four instance methods from the module Crypt::Extensions::InstanceMethods and two class methods from Crypt::Extensions::ClassMethods – for specifics, please refer there.

The two main instance methods are #encr and #decr, which as the name implies, perform two-way symmetric encryption and decryption of any Ruby object that can be marshaled.

Two additional instance methods #encr_password and #decr_password turn on password-based encryption, which actually uses a password to construct a 128-bit long private key, and then uses that in the encryption of the data. You could use them to encrypt data with a password instead of a randomly generated private key.

Create a new key with #create_private_key class method, which returns a new key every time it’s called, or with #private_key class method, which either assigns, or creates and caches the private key at a class level.

Example

require 'sym/crypt'

class TestClass
  include Sym::Crypt
  # read the key from environmant variable and assign to this class.
  private_key ENV['PRIVATE_KEY']

  def sensitive_value=(value)
    @sensitive_value = encr(value, self.class.private_key)
  end

  def sensitive_value
    decr(@sensitive_value, self.class.private_key)
  end
end

Private Key

They private key can be generated by TestClass.create_private_key which returns but does not store a new random 256-bit key.

The key can be assigned and saved, or auto-generated and saved using the #private_key method on the class that includes the Sym module.

Each class including the Sym module would get their own +#private_key# class-instance variable accessor, and a possible value.

Defined Under Namespace

Modules: Configurable, Crypt, Data