Module: SecureDBFields::ActiveRecord::ClassMethods

Defined in:
lib/secure_db_fields/active_record.rb

Instance Method Summary collapse

Instance Method Details

#secure_db_field(name, encrypted:, blind_index:, row_uid: :secure_row_uid, normalizer: nil, keyring: SecureDBFields::Keyring.new, table_name_for_aad: nil, key_domain: nil) ⇒ Object



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# File 'lib/secure_db_fields/active_record.rb', line 10

def secure_db_field(name, encrypted:, blind_index:, row_uid: :secure_row_uid, normalizer: nil, keyring: SecureDBFields::Keyring.new, table_name_for_aad: nil, key_domain: nil)
  field_name = name.to_s
  if normalizer == :phone || (normalizer.nil? && field_name == "phone")
    normalizer = ->(value) { value.nil? ? nil : SecureDBFields::Phone.assert_canonical_e164!(value) }
    key_domain ||= "PHONE"
  end
  normalizer ||= ->(value) { value.nil? ? nil : value.to_s }
  table_for_aad = table_name_for_aad || table_name
  domain = key_domain || "#{table_for_aad}_#{field_name}"

  define_method(name) do
    envelope = public_send(encrypted)
    return nil if envelope.nil?

    key_id = SecureDBFields::Crypto.key_id(envelope)
    key = keyring.encryption_key(key_id)
    uid = public_send(row_uid)
    SecureDBFields::Crypto.decrypt(envelope, key: key, aad: SecureDBFields::Crypto.aad(table_for_aad, field_name, uid))
  end

  define_method("#{name}=") do |value|
    uid = public_send(row_uid)
    if uid.nil? || uid.to_s.b.bytesize != 16
      raise ArgumentError, "#{row_uid} must be 16 bytes before encrypting #{field_name}"
    end

    if value.nil?
      public_send("#{encrypted}=", nil)
      public_send("#{blind_index}=", nil)
      next nil
    end

    normalized = normalizer.call(value)
    key_id = keyring.active_key_id
    enc_key = keyring.encryption_key(key_id)
    bidx_key = keyring.blind_index_key(domain)
    public_send("#{encrypted}=", SecureDBFields::Crypto.encrypt(normalized, key: enc_key, aad: SecureDBFields::Crypto.aad(table_for_aad, field_name, uid), key_id: key_id))
    public_send("#{blind_index}=", SecureDBFields::Crypto.blind_index(normalized, key: bidx_key))
  end

  define_singleton_method("#{name}_blind_index_for") do |value|
    normalized = normalizer.call(value)
    return nil if normalized.nil?
    SecureDBFields::Crypto.blind_index(normalized, key: keyring.blind_index_key(domain))
  end
end