lib/attr_encrypted.rb
# frozen_string_literal: true
require 'encryptor'
# Adds attr_accessors that encrypt and decrypt an object's attributes
module AttrEncrypted
autoload :Version, 'attr_encrypted/version'
def self.extended(base) # :nodoc:
base.class_eval do
include InstanceMethods
attr_writer :attr_encrypted_options
@attr_encrypted_options, @attr_encrypted_encrypted_attributes = {}, {}
end
end
# Generates attr_accessors that encrypt and decrypt attributes transparently
#
# Options (any other options you specify are passed to the Encryptor's encrypt and decrypt methods)
#
# attribute: The name of the referenced encrypted attribute. For example
# <tt>attr_accessor :email, attribute: :ee</tt> would generate an
# attribute named 'ee' to store the encrypted email. This is useful when defining
# one attribute to encrypt at a time or when the :prefix and :suffix options
# aren't enough.
# Defaults to nil.
#
# prefix: A prefix used to generate the name of the referenced encrypted attributes.
# For example <tt>attr_accessor :email, prefix: 'crypted_'</tt> would
# generate attributes named 'crypted_email' to store the encrypted
# email and password.
# Defaults to 'encrypted_'.
#
# suffix: A suffix used to generate the name of the referenced encrypted attributes.
# For example <tt>attr_accessor :email, prefix: '', suffix: '_encrypted'</tt>
# would generate attributes named 'email_encrypted' to store the
# encrypted email.
# Defaults to ''.
#
# key: The encryption key. This option may not be required if
# you're using a custom encryptor. If you pass a symbol
# representing an instance method then the :key option
# will be replaced with the result of the method before
# being passed to the encryptor. Objects that respond
# to :call are evaluated as well (including procs).
# Any other key types will be passed directly to the encryptor.
# Defaults to nil.
#
# encode: If set to true, attributes will be encoded as well as
# encrypted. This is useful if you're planning on storing
# the encrypted attributes in a database. The default
# encoding is 'm' (base64), however this can be overwritten
# by setting the :encode option to some other encoding
# string instead of just 'true'. See
# http://www.ruby-doc.org/core/classes/Array.html#M002245
# for more encoding directives.
# Defaults to false unless you're using it with ActiveRecord or Sequel.
#
# encode_iv: Defaults to true.
# encode_salt: Defaults to true.
#
# default_encoding: Defaults to 'm' (base64).
#
# marshal: If set to true, attributes will be marshaled as well
# as encrypted. This is useful if you're planning on
# encrypting something other than a string.
# Defaults to false.
#
# marshaler: The object to use for marshaling.
# Defaults to Marshal.
#
# dump_method: The dump method name to call on the <tt>:marshaler</tt> object to.
# Defaults to 'dump'.
#
# load_method: The load method name to call on the <tt>:marshaler</tt> object.
# Defaults to 'load'.
#
# encryptor: The object to use for encrypting.
# Defaults to Encryptor.
#
# encrypt_method: The encrypt method name to call on the <tt>:encryptor</tt> object.
# Defaults to 'encrypt'.
#
# decrypt_method: The decrypt method name to call on the <tt>:encryptor</tt> object.
# Defaults to 'decrypt'.
#
# if: Attributes are only encrypted if this option evaluates
# to true. If you pass a symbol representing an instance
# method then the result of the method will be evaluated.
# Any objects that respond to <tt>:call</tt> are evaluated as well.
# Defaults to true.
#
# unless: Attributes are only encrypted if this option evaluates
# to false. If you pass a symbol representing an instance
# method then the result of the method will be evaluated.
# Any objects that respond to <tt>:call</tt> are evaluated as well.
# Defaults to false.
#
# mode: Selects encryption mode for attribute: choose <tt>:single_iv_and_salt</tt> for compatibility
# with the old attr_encrypted API: the IV is derived from the encryption key by the underlying Encryptor class; salt is not used.
# The <tt>:per_attribute_iv_and_salt</tt> mode uses a per-attribute IV and salt. The salt is used to derive a unique key per attribute.
# A <tt>:per_attribute_iv</default> mode derives a unique IV per attribute; salt is not used.
# Defaults to <tt>:per_attribute_iv</tt>.
#
# allow_empty_value: Attributes which have nil or empty string values will not be encrypted unless this option
# has a truthy value.
#
# You can specify your own default options
#
# class User
# # Now all attributes will be encoded and marshaled by default
# attr_encrypted_options.merge!(encode: true, marshal: true, some_other_option: true)
# attr_encrypted :configuration, key: 'my secret key'
# end
#
#
# Example
#
# class User
# attr_encrypted :email, key: 'some secret key'
# attr_encrypted :configuration, key: 'some other secret key', marshal: true
# end
#
# @user = User.new
# @user.encrypted_email # nil
# @user.email? # false
# @user.email = 'test@example.com'
# @user.email? # true
# @user.encrypted_email # returns the encrypted version of 'test@example.com'
#
# @user.configuration = { time_zone: 'UTC' }
# @user.encrypted_configuration # returns the encrypted version of configuration
#
# See README for more examples
def attr_encrypted(*attributes)
options = attributes.last.is_a?(Hash) ? attributes.pop : {}
options = attr_encrypted_default_options.dup.merge!(attr_encrypted_options).merge!(options)
options[:encode] = options[:default_encoding] if options[:encode] == true
options[:encode_iv] = options[:default_encoding] if options[:encode_iv] == true
options[:encode_salt] = options[:default_encoding] if options[:encode_salt] == true
attributes.each do |attribute|
encrypted_attribute_name = (options[:attribute] ? options[:attribute] : [options[:prefix], attribute, options[:suffix]].join).to_sym
instance_methods_as_symbols = attribute_instance_methods_as_symbols
if attribute_instance_methods_as_symbols_available?
attr_reader encrypted_attribute_name unless instance_methods_as_symbols.include?(encrypted_attribute_name)
attr_writer encrypted_attribute_name unless instance_methods_as_symbols.include?(:"#{encrypted_attribute_name}=")
iv_name = "#{encrypted_attribute_name}_iv".to_sym
attr_reader iv_name unless instance_methods_as_symbols.include?(iv_name)
attr_writer iv_name unless instance_methods_as_symbols.include?(:"#{iv_name}=")
salt_name = "#{encrypted_attribute_name}_salt".to_sym
attr_reader salt_name unless instance_methods_as_symbols.include?(salt_name)
attr_writer salt_name unless instance_methods_as_symbols.include?(:"#{salt_name}=")
end
define_method(attribute) do
instance_variable_get("@#{attribute}") || instance_variable_set("@#{attribute}", attr_encrypted_decrypt(attribute, send(encrypted_attribute_name)))
end
define_method("#{attribute}=") do |value|
send("#{encrypted_attribute_name}=", attr_encrypted_encrypt(attribute, value))
instance_variable_set("@#{attribute}", value)
end
define_method("#{attribute}?") do
value = send(attribute)
value.respond_to?(:empty?) ? !value.empty? : !!value
end
self.attr_encrypted_encrypted_attributes[attribute.to_sym] = options.merge(attribute: encrypted_attribute_name)
end
end
alias_method :attr_encryptor, :attr_encrypted
# Default options to use with calls to <tt>attr_encrypted</tt>
#
# It will inherit existing options from its superclass
def attr_encrypted_options
@attr_encrypted_options ||= superclass.attr_encrypted_options.dup
end
def attr_encrypted_default_options
{
prefix: 'encrypted_',
suffix: '',
if: true,
unless: false,
encode: false,
encode_iv: true,
encode_salt: true,
default_encoding: 'm',
marshal: false,
marshaler: Marshal,
dump_method: 'dump',
load_method: 'load',
encryptor: Encryptor,
encrypt_method: 'encrypt',
decrypt_method: 'decrypt',
mode: :per_attribute_iv,
algorithm: 'aes-256-gcm',
allow_empty_value: false,
}
end
private :attr_encrypted_default_options
# Checks if an attribute is configured with <tt>attr_encrypted</tt>
#
# Example
#
# class User
# attr_accessor :name
# attr_encrypted :email
# end
#
# User.attr_encrypted?(:name) # false
# User.attr_encrypted?(:email) # true
def attr_encrypted?(attribute)
attr_encrypted_encrypted_attributes.has_key?(attribute.to_sym)
end
# Decrypts a value for the attribute specified
#
# Example
#
# class User
# attr_encrypted :email
# end
#
# email = User.attr_encrypted_decrypt(:email, 'SOME_ENCRYPTED_EMAIL_STRING')
def attr_encrypted_decrypt(attribute, encrypted_value, options = {})
options = attr_encrypted_encrypted_attributes[attribute.to_sym].merge(options)
if options[:if] && !options[:unless] && not_empty?(encrypted_value)
encrypted_value = encrypted_value.unpack(options[:encode]).first if options[:encode]
value = options[:encryptor].send(options[:decrypt_method], options.merge!(value: encrypted_value))
if options[:marshal]
value = options[:marshaler].send(options[:load_method], value)
elsif defined?(Encoding)
encoding = Encoding.default_internal || Encoding.default_external
value = value.force_encoding(encoding.name)
end
value
else
encrypted_value
end
end
# Encrypts a value for the attribute specified
#
# Example
#
# class User
# attr_encrypted :email
# end
#
# encrypted_email = User.attr_encrypted_encrypt(:email, 'test@example.com')
def attr_encrypted_encrypt(attribute, value, options = {})
options = attr_encrypted_encrypted_attributes[attribute.to_sym].merge(options)
if options[:if] && !options[:unless] && (options[:allow_empty_value] || not_empty?(value))
value = options[:marshal] ? options[:marshaler].send(options[:dump_method], value) : value.to_s
encrypted_value = options[:encryptor].send(options[:encrypt_method], options.merge!(value: value))
encrypted_value = [encrypted_value].pack(options[:encode]) if options[:encode]
encrypted_value
else
value
end
end
def not_empty?(value)
!value.nil? && !(value.is_a?(String) && value.empty?)
end
# Contains a hash of encrypted attributes with virtual attribute names as keys
# and their corresponding options as values
#
# Example
#
# class User
# attr_encrypted :email, key: 'my secret key'
# end
#
# User.attr_encrypted_encrypted_attributes # { email: { attribute: 'encrypted_email', key: 'my secret key' } }
def attr_encrypted_encrypted_attributes
@attr_encrypted_encrypted_attributes ||= superclass.attr_encrypted_encrypted_attributes.dup
end
# Forwards calls to :encrypt_#{attribute} or :decrypt_#{attribute} to the corresponding encrypt or decrypt method
# if attribute was configured with attr_encrypted
#
# Example
#
# class User
# attr_encrypted :email, key: 'my secret key'
# end
#
# User.encrypt_email('SOME_ENCRYPTED_EMAIL_STRING')
def method_missing(method, *arguments, &block)
if method.to_s =~ /^((en|de)crypt)_(.+)$/ && attr_encrypted?($3)
send("attr_encrypted_#{$1}", $3, *arguments)
else
super
end
end
module InstanceMethods
# Decrypts a value for the attribute specified using options evaluated in the current object's scope
#
# Example
#
# class User
# attr_accessor :secret_key
# attr_encrypted :email, key: :secret_key
#
# def initialize(secret_key)
# self.secret_key = secret_key
# end
# end
#
# @user = User.new('some-secret-key')
# @user.decrypt(:email, 'SOME_ENCRYPTED_EMAIL_STRING')
def attr_encrypted_decrypt(attribute, encrypted_value)
attr_encrypted_encrypted_attributes[attribute.to_sym][:operation] = :decrypting
attr_encrypted_encrypted_attributes[attribute.to_sym][:value_present] = self.class.not_empty?(encrypted_value)
self.class.attr_encrypted_decrypt(attribute, encrypted_value, evaluated_attr_encrypted_options_for(attribute))
end
# Encrypts a value for the attribute specified using options evaluated in the current object's scope
#
# Example
#
# class User
# attr_accessor :secret_key
# attr_encrypted :email, key: :secret_key
#
# def initialize(secret_key)
# self.secret_key = secret_key
# end
# end
#
# @user = User.new('some-secret-key')
# @user.attr_encrypted_encrypt(:email, 'test@example.com')
def attr_encrypted_encrypt(attribute, value)
attr_encrypted_encrypted_attributes[attribute.to_sym][:operation] = :encrypting
attr_encrypted_encrypted_attributes[attribute.to_sym][:value_present] = self.class.not_empty?(value)
self.class.attr_encrypted_encrypt(attribute, value, evaluated_attr_encrypted_options_for(attribute))
end
# Copies the class level hash of encrypted attributes with virtual attribute names as keys
# and their corresponding options as values to the instance
#
def attr_encrypted_encrypted_attributes
@attr_encrypted_encrypted_attributes ||= begin
duplicated= {}
self.class.attr_encrypted_encrypted_attributes.map { |key, value| duplicated[key] = value.dup }
duplicated
end
end
protected
# Returns attr_encrypted options evaluated in the current object's scope for the attribute specified
def evaluated_attr_encrypted_options_for(attribute)
evaluated_options = Hash.new
attributes = attr_encrypted_encrypted_attributes[attribute.to_sym]
attribute_option_value = attributes[:attribute]
[:if, :unless, :value_present, :allow_empty_value].each do |option|
evaluated_options[option] = evaluate_attr_encrypted_option(attributes[option])
end
evaluated_options[:attribute] = attribute_option_value
evaluated_options.tap do |options|
if options[:if] && !options[:unless] && options[:value_present] || options[:allow_empty_value]
(attributes.keys - evaluated_options.keys).each do |option|
options[option] = evaluate_attr_encrypted_option(attributes[option])
end
unless options[:mode] == :single_iv_and_salt
load_iv_for_attribute(attribute, options)
end
if options[:mode] == :per_attribute_iv_and_salt
load_salt_for_attribute(attribute, options)
end
end
end
end
# Evaluates symbol (method reference) or proc (responds to call) options
#
# If the option is not a symbol or proc then the original option is returned
def evaluate_attr_encrypted_option(option)
if option.is_a?(Symbol) && respond_to?(option, true)
send(option)
elsif option.respond_to?(:call)
option.call(self)
else
option
end
end
def load_iv_for_attribute(attribute, options)
encrypted_attribute_name = options[:attribute]
encode_iv = options[:encode_iv]
iv = options[:iv] || send("#{encrypted_attribute_name}_iv")
if options[:operation] == :encrypting
begin
iv = generate_iv(options[:algorithm])
iv = [iv].pack(encode_iv) if encode_iv
send("#{encrypted_attribute_name}_iv=", iv)
rescue RuntimeError
end
end
if iv && !iv.empty?
iv = iv.unpack(encode_iv).first if encode_iv
options[:iv] = iv
end
end
def generate_iv(algorithm)
algo = OpenSSL::Cipher.new(algorithm)
algo.encrypt
algo.random_iv
end
def load_salt_for_attribute(attribute, options)
encrypted_attribute_name = options[:attribute]
encode_salt = options[:encode_salt]
salt = options[:salt] || send("#{encrypted_attribute_name}_salt")
if options[:operation] == :encrypting
salt = SecureRandom.random_bytes
salt = prefix_and_encode_salt(salt, encode_salt) if encode_salt
send("#{encrypted_attribute_name}_salt=", salt)
end
if salt && !salt.empty?
salt = decode_salt_if_encoded(salt, encode_salt) if encode_salt
options[:salt] = salt
end
end
def prefix_and_encode_salt(salt, encoding)
prefix = '_'
prefix + [salt].pack(encoding)
end
def decode_salt_if_encoded(salt, encoding)
prefix = '_'
salt.slice(0).eql?(prefix) ? salt.slice(1..-1).unpack(encoding).first : salt
end
end
protected
def attribute_instance_methods_as_symbols
instance_methods.collect { |method| method.to_sym }
end
def attribute_instance_methods_as_symbols_available?
true
end
end
Dir[File.join(File.dirname(__FILE__), 'attr_encrypted', 'adapters', '*.rb')].each { |adapter| require adapter }