Class: ActiveRecord::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/symmetric_encryption/extensions/active_record/base.rb

Class Method Summary collapse

Class Method Details

.attr_encrypted(*params) ⇒ Object

Drop in replacement for attr_encrypted gem, except that it uses SymmetricEncryption for managing the encryption key

Parameters:

  • Symbolic names of each method to create which has a corresponding method already defined in rails starting with: encrypted_

  • Followed by an optional hash:

    :random_iv [true|false]
  Whether the encrypted value should use a random IV every time the
  field is encrypted.
  It is recommended to set this to true where feasible. If the encrypted
  value could be used as part of a SQL where clause, or as part
  of any lookup, then it must be false.
  Setting random_iv to true will result in a different encrypted output for
  the same input string.
  Note: Only set to true if the field will never be used as part of
    the where clause in an SQL query.
  Note: When random_iv is true it will add a 8 byte header, plus the bytes
    to store the random IV in every returned encrypted string, prior to the
    encoding if any.
  Default: false
  Highly Recommended where feasible: true

:type [Symbol]
  The type for this field, #see SymmetricEncryption::COERCION_TYPES
  Default: :string

:compress [true|false]
  Whether to compress str before encryption
  Should only be used for large strings since compression overhead and
  the overhead of adding the 'magic' header may exceed any benefits of
  compression
  Note: Adds a 6 byte header prior to encoding, only if :random_iv is false
  Default: false



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# File 'lib/symmetric_encryption/extensions/active_record/base.rb', line 39

def attr_encrypted(*params)
  # Ensure ActiveRecord has created all its methods first
  # Ignore failures since the table may not yet actually exist
  define_attribute_methods rescue nil

  options   = params.last.is_a?(Hash) ? params.pop.dup : {}
  random_iv = options.delete(:random_iv) || false
  compress  = options.delete(:compress) || false
  type      = options.delete(:type) || :string

  raise "Invalid type: #{type.inspect}. Valid types: #{SymmetricEncryption::COERCION_TYPES.inspect}" unless SymmetricEncryption::COERCION_TYPES.include?(type)

  # For backward compatibility
  if options.delete(:marshal) == true
    warn("The :marshal option has been deprecated in favor of :type. For example: attr_encrypted name, :type => :yaml")
    raise "Marshal is depreacted and cannot be used in conjunction with :type, just use :type. For #{params.inspect}" if type != :string
    type = :yaml
  end

  options.each {|option| warn "Ignoring unknown option #{option.inspect} supplied to attr_encrypted with #{params.inspect}"}

  if const_defined?(:EncryptedAttributes, _search_ancestors = false)
    mod = const_get(:EncryptedAttributes)
  else
    mod = const_set(:EncryptedAttributes, Module.new)
    include mod
  end

  params.each do |attribute|
    # Generate unencrypted attribute with getter and setter
    mod.module_eval("      # Returns the decrypted value for the encrypted attribute\n      # The decrypted value is cached and is only decrypted if the encrypted value has changed\n      # If this method is not called, then the encrypted value is never decrypted\n      def \#{attribute}\n        if @stored_encrypted_\#{attribute} != self.encrypted_\#{attribute}\n          @\#{attribute} = ::SymmetricEncryption.decrypt(self.encrypted_\#{attribute},version=nil,:\#{type}).freeze\n          @stored_encrypted_\#{attribute} = self.encrypted_\#{attribute}\n        end\n        @\#{attribute}\n      end\n\n      # Set the un-encrypted attribute\n      # Also updates the encrypted field with the encrypted value\n      def \#{attribute}=(value)\n        v = SymmetricEncryption::coerce(value, :\#{type})\n        self.encrypted_\#{attribute} = @stored_encrypted_\#{attribute} = ::SymmetricEncryption.encrypt(v,\#{random_iv},\#{compress},:\#{type})\n        @\#{attribute} = v.freeze\n      end\n    UNENCRYPTED\n\n    encrypted_attributes[attribute.to_sym] = \"encrypted_\#{attribute}\".to_sym\n  end\nend\n", __FILE__, __LINE__ + 1)

.encrypted_attribute?(attribute) ⇒ Boolean

Returns whether an attribute has been configured to be encrypted

Example

class User < ActiveRecord::Base
  attr_accessor :name
  attr_encrypted :email
end

User.encrypted_attribute?(:name) # false
User.encrypted_attribute?(:email) # true

Returns:

  • (Boolean) 


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# File 'lib/symmetric_encryption/extensions/active_record/base.rb', line 131

def encrypted_attribute?(attribute)
  encrypted_keys.include?(attribute)
end

.encrypted_attributes ⇒ Object

Contains a hash of encrypted attributes with virtual attribute names as keys and real attribute names as values

Example

class User < ActiveRecord::Base
  attr_encrypted :email
end

User.encrypted_attributes # { :email => :encrypted_email }



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# File 'lib/symmetric_encryption/extensions/active_record/base.rb', line 104

def encrypted_attributes
  @encrypted_attributes ||= superclass.respond_to?(:encrypted_attributes) ? superclass.encrypted_attributes.dup : {}
end

.encrypted_column?(attribute) ⇒ Boolean

Returns whether the attribute is the database column to hold the encrypted data for a matching encrypted attribute

Example

class User < ActiveRecord::Base
  attr_accessor :name
  attr_encrypted :email
end

User.encrypted_column?(:encrypted_name) # false
User.encrypted_column?(:encrypted_email) # true

Returns:

  • (Boolean) 


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# File 'lib/symmetric_encryption/extensions/active_record/base.rb', line 147

def encrypted_column?(attribute)
  encrypted_columns.include?(attribute)
end

.encrypted_columns ⇒ Object

Return the name of all encrypted columns as an Array of symbols Example: [:encrypted_email, :encrypted_password]



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# File 'lib/symmetric_encryption/extensions/active_record/base.rb', line 116

def encrypted_columns
  @encrypted_columns ||= encrypted_attributes.values
end

.encrypted_keys ⇒ Object

Return the name of all encrypted virtual attributes as an Array of symbols Example: [:email, :password]



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# File 'lib/symmetric_encryption/extensions/active_record/base.rb', line 110

def encrypted_keys
  @encrypted_keys ||= encrypted_attributes.keys
end