class ActiveRecord::Encryption::Encryptor

An encryptor exposes the encryption API that ActiveRecord::Encryption::EncryptedAttributeType uses for encrypting and decrypting attribute values.

It interacts with a KeyProvider for getting the keys, and delegate to ActiveRecord::Encryption::Cipher the actual encryption algorithm.

Constants

DECRYPT_ERRORS
ENCODING_ERRORS
THRESHOLD_TO_JUSTIFY_COMPRESSION

Public Instance Methods

decrypt(encrypted_text, key_provider: default_key_provider, cipher_options: {}) click to toggle source

Decrypts a clean_text and returns the result as clean text

Options

:key_provider

Key provider to use for the encryption operation. It will default to ActiveRecord::Encryption.key_provider when not provided

:cipher_options

Cipher-specific options that will be passed to the Cipher configured in ActiveRecord::Encryption.cipher

# File lib/active_record/encryption/encryptor.rb, line 52
def decrypt(encrypted_text, key_provider: default_key_provider, cipher_options: {})
  message = deserialize_message(encrypted_text)
  keys = key_provider.decryption_keys(message)
  raise Errors::Decryption unless keys.present?
  uncompress_if_needed(cipher.decrypt(message, key: keys.collect(&:secret), **cipher_options), message.headers.compressed)
rescue *(ENCODING_ERRORS + DECRYPT_ERRORS)
  raise Errors::Decryption
end
encrypt(clear_text, key_provider: default_key_provider, cipher_options: {}) click to toggle source

Encrypts clean_text and returns the encrypted result

Internally, it will:

  1. Create a new ActiveRecord::Encryption::Message

  2. Compress and encrypt clean_text as the message payload

  3. Serialize it with ActiveRecord::Encryption.message_serializer (ActiveRecord::Encryption::SafeMarshal by default)

  4. Encode the result with Base 64

Options

:key_provider

Key provider to use for the encryption operation. It will default to ActiveRecord::Encryption.key_provider when not provided

:cipher_options

Cipher-specific options that will be passed to the Cipher configured in ActiveRecord::Encryption.cipher

# File lib/active_record/encryption/encryptor.rb, line 34
def encrypt(clear_text, key_provider: default_key_provider, cipher_options: {})
  clear_text = force_encoding_if_needed(clear_text) if cipher_options[:deterministic]

  validate_payload_type(clear_text)
  serialize_message build_encrypted_message(clear_text, key_provider: key_provider, cipher_options: cipher_options)
end
encrypted?(text) click to toggle source

Returns whether the text is encrypted or not

# File lib/active_record/encryption/encryptor.rb, line 62
def encrypted?(text)
  deserialize_message(text)
  true
rescue Errors::Encoding, *DECRYPT_ERRORS
  false
end

Private Instance Methods

build_encrypted_message(clear_text, key_provider:, cipher_options:) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 88
def build_encrypted_message(clear_text, key_provider:, cipher_options:)
  key = key_provider.encryption_key

  clear_text, was_compressed = compress_if_worth_it(clear_text)
  cipher.encrypt(clear_text, key: key.secret, **cipher_options).tap do |message|
    message.headers.add(key.public_tags)
    message.headers.compressed = true if was_compressed
  end
end
cipher() click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 84
def cipher
  ActiveRecord::Encryption.cipher
end
compress(data) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 122
def compress(data)
  Zlib::Deflate.deflate(data).tap do |compressed_data|
    compressed_data.force_encoding(data.encoding)
  end
end
compress_if_worth_it(string) click to toggle source

Under certain threshold, ZIP compression is actually worse that not compressing

# File lib/active_record/encryption/encryptor.rb, line 114
def compress_if_worth_it(string)
  if string.bytesize > THRESHOLD_TO_JUSTIFY_COMPRESSION
    [compress(string), true]
  else
    [string, false]
  end
end
default_key_provider() click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 74
def default_key_provider
  ActiveRecord::Encryption.key_provider
end
deserialize_message(message) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 102
def deserialize_message(message)
  raise Errors::Encoding unless message.is_a?(String)
  serializer.load message
rescue ArgumentError, TypeError, Errors::ForbiddenClass
  raise Errors::Encoding
end
force_encoding_if_needed(value) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 142
def force_encoding_if_needed(value)
  if forced_encoding_for_deterministic_encryption && value && value.encoding != forced_encoding_for_deterministic_encryption
    value.encode(forced_encoding_for_deterministic_encryption, invalid: :replace, undef: :replace)
  else
    value
  end
end
forced_encoding_for_deterministic_encryption() click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 150
def forced_encoding_for_deterministic_encryption
  ActiveRecord::Encryption.config.forced_encoding_for_deterministic_encryption
end
serialize_message(message) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 98
def serialize_message(message)
  serializer.dump(message)
end
serializer() click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 109
def serializer
  ActiveRecord::Encryption.message_serializer
end
uncompress(data) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 136
def uncompress(data)
  Zlib::Inflate.inflate(data).tap do |uncompressed_data|
    uncompressed_data.force_encoding(data.encoding)
  end
end
uncompress_if_needed(data, compressed) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 128
def uncompress_if_needed(data, compressed)
  if compressed
    uncompress(data)
  else
    data
  end
end
validate_payload_type(clear_text) click to toggle source
# File lib/active_record/encryption/encryptor.rb, line 78
def validate_payload_type(clear_text)
  unless clear_text.is_a?(String)
    raise ActiveRecord::Encryption::Errors::ForbiddenClass, "The encryptor can only encrypt string values (#{clear_text.class})"
  end
end