This is the concern mixed in Active Record models to make them encryptable. It adds the encrypts attribute declaration, as well as the API to encrypt and decrypt records.

Methods

Constants

ORIGINAL_ATTRIBUTE_PREFIX = "original_"
 

Instance Public methods

add_length_validation_for_encrypted_columns()

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 127
def add_length_validation_for_encrypted_columns
  encrypted_attributes&.each do |attribute_name|
    validate_column_size attribute_name
  end
end

ciphertext_for(attribute_name)

Returns the ciphertext for attribute_name.

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 146
def ciphertext_for(attribute_name)
  read_attribute_before_type_cast(attribute_name)
end

decrypt()

Decrypts all the encryptable attributes and saves the changes.

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 156
def decrypt
  decrypt_attributes if has_encrypted_attributes?
end

deterministic_encrypted_attributes()

Returns the list of deterministic encryptable attributes in the model class.

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 56
def deterministic_encrypted_attributes
  @deterministic_encrypted_attributes ||= encrypted_attributes&.find_all do |attribute_name|
    type_for_attribute(attribute_name).deterministic?
  end
end

encrypt()

Encrypts all the encryptable attributes and saves the changes.

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 151
def encrypt
  encrypt_attributes if has_encrypted_attributes?
end

encrypt_attribute(name, attribute_scheme)

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 82
def encrypt_attribute(name, attribute_scheme)
  encrypted_attributes << name.to_sym

  attribute name do |cast_type|
    ActiveRecord::Encryption::EncryptedAttributeType.new scheme: attribute_scheme, cast_type: cast_type
  end

  preserve_original_encrypted(name) if attribute_scheme.ignore_case?
  ActiveRecord::Encryption.encrypted_attribute_was_declared(self, name)
end

encrypted_attribute?(attribute_name)

Returns whether a given attribute is encrypted or not.

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 141
def encrypted_attribute?(attribute_name)
  ActiveRecord::Encryption.encryptor.encrypted? ciphertext_for(attribute_name)
end

encrypts(*names, key_provider: nil, key: nil, deterministic: false, downcase: false, ignore_case: false, previous: [], **context_properties)

Encrypts the name attribute.

Options

  • :key_provider - A key provider to provide encryption and decryption keys. Defaults to ActiveRecord::Encryption.key_provider.

  • :key - A password to derive the key from. It's a shorthand for a :key_provider that serves derivated keys. Both options can't be used at the same time.

  • :deterministic - By default, encryption is not deterministic. It will use a random initialization vector for each encryption operation. This means that encrypting the same content with the same key twice will generate different ciphertexts. When set to true, it will generate the initialization vector based on the encrypted content. This means that the same content will generate the same ciphertexts. This enables querying encrypted text with Active Record. Deterministic encryption will use the oldest encryption scheme to encrypt new data by default. You can change this by setting +deterministic: { fixed: false }+. That will make it use the newest encryption scheme for encrypting new data.

  • :downcase - When true, it converts the encrypted content to downcase automatically. This allows to effectively ignore case when querying data. Notice that the case is lost. Use :ignore_case if you are interested in preserving it.

  • :ignore_case - When true, it behaves like :downcase but, it also preserves the original case in a specially designated column +original_<name>+. When reading the encrypted content, the version with the original case is served. But you can still execute queries that will ignore the case. This option can only be used when :deterministic is true.

  • :context_properties - Additional properties that will override Context settings when this attribute is encrypted and decrypted. E.g: encryptor:, cipher:, message_serializer:, etc.

  • :previous - List of previous encryption schemes. When provided, they will be used in order when trying to read the attribute. Each entry of the list can contain the properties supported by encrypts. Also, when deterministic encryption is used, they will be used to generate additional ciphertexts to check in the queries.

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 45
def encrypts(*names, key_provider: nil, key: nil, deterministic: false, downcase: false, ignore_case: false, previous: [], **context_properties)
  self.encrypted_attributes ||= Set.new # not using :default because the instance would be shared across classes
  scheme = scheme_for key_provider: key_provider, key: key, deterministic: deterministic, downcase: downcase, \
      ignore_case: ignore_case, previous: previous, **context_properties

  names.each do |name|
    encrypt_attribute name, scheme
  end
end

global_previous_schemes_for(scheme)

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 76
def global_previous_schemes_for(scheme)
  ActiveRecord::Encryption.config.previous_schemes.collect do |previous_scheme|
    scheme.merge(previous_scheme)
  end
end

load_schema!()

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 121
def load_schema!
  super

  add_length_validation_for_encrypted_columns if ActiveRecord::Encryption.config.validate_column_size
end

override_accessors_to_preserve_original(name, original_attribute_name)

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 104
def override_accessors_to_preserve_original(name, original_attribute_name)
  include(Module.new do
    define_method name do
      if ((value = super()) && encrypted_attribute?(name)) || !ActiveRecord::Encryption.config.support_unencrypted_data
        send(original_attribute_name)
      else
        value
      end
    end

    define_method "#{name}=" do |value|
      self.send "#{original_attribute_name}=", value
      super(value)
    end
  end)
end

preserve_original_encrypted(name)

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 93
def preserve_original_encrypted(name)
  original_attribute_name = "#{ORIGINAL_ATTRIBUTE_PREFIX}#{name}".to_sym

  if !ActiveRecord::Encryption.config.support_unencrypted_data && !column_names.include?(original_attribute_name.to_s)
    raise Errors::Configuration, "To use :ignore_case for '#{name}' you must create an additional column named '#{original_attribute_name}'"
  end

  encrypts original_attribute_name
  override_accessors_to_preserve_original name, original_attribute_name
end

scheme_for(key_provider: nil, key: nil, deterministic: false, downcase: false, ignore_case: false, previous: [], **context_properties)

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 68
def scheme_for(key_provider: nil, key: nil, deterministic: false, downcase: false, ignore_case: false, previous: [], **context_properties)
  ActiveRecord::Encryption::Scheme.new(key_provider: key_provider, key: key, deterministic: deterministic,
                                       downcase: downcase, ignore_case: ignore_case, **context_properties).tap do |scheme|
    scheme.previous_schemes = global_previous_schemes_for(scheme) +
      Array.wrap(previous).collect { |scheme_config| ActiveRecord::Encryption::Scheme.new(**scheme_config) }
  end
end

source_attribute_from_preserved_attribute(attribute_name)

Given a attribute name, it returns the name of the source attribute when it's a preserved one.

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 63
def source_attribute_from_preserved_attribute(attribute_name)
  attribute_name.to_s.sub(ORIGINAL_ATTRIBUTE_PREFIX, "") if /^#{ORIGINAL_ATTRIBUTE_PREFIX}/.match?(attribute_name)
end

validate_column_size(attribute_name)

# File activerecord/lib/active_record/encryption/encryptable_record.rb, line 133
def validate_column_size(attribute_name)
  if limit = columns_hash[attribute_name.to_s]&.limit
    validates_length_of attribute_name, maximum: limit
  end
end