mongoid-encrypted-fields

Build Status Code Climate Coverage Status Dependency Status

A library for storing encrypted data in Mongo using Mongoid. We looked at a few alternatives, but wanted something that stored the values securely and unobtrusively.

Mongoid 3 supports custom types that need to only provide a simple interface - allowing us to extend core Ruby types to secure any type while providing a clean interface for developers.

Queries encrypt data before searching the database, so equality matches work automatically.

Prerequisites

  • >= Ruby 1.9.3
  • >= Mongoid 3.0
  • "Bring your own" encryption, see below

Install

gem 'mongoid-encrypted-fields'

Usage

  • Configure the cipher to be used for encrypting field values:

    GibberishCipher can be found in examples - uses the Gibberish gem:

    Mongoid::EncryptedFields.cipher = GibberishCipher.new(ENV['MY_PASSWORD'], ENV['MY_SALT'])

  • Use encrypted types for fields in your models:

    class Person
    include Mongoid::Document

    field :name, type: String
    field :ssn, type: Mongoid::EncryptedString
end

  • The field getter returns the unencrypted value:

    person = Person.new(ssn: '123456789')
person.ssn # => '123456789'

  • The encrypted value is accessible with the "encrypted" attribute

    person.ssn.encrypted # => <encrypted string>

# It can also be accessed using the hash syntax supported by Mongoid
person[:ssn] # => <encrypted string>

  • Finding a model by an encrypted field works automatically (equality only):

    Person.where(ssn: '123456789').count() # ssn is encrypted before querying the database

  • The Mongoid uniqueness validator is patched to detect encrypted fields:

    class Person
    ...
    field :ssn, type: Mongoid::EncryptedString
    validates_uniqueness_of :ssn, case_sensitive: true # Works as expected
    validates_uniqueness_of :ssn, case_sensitive: false # Raises exception - encrypted field cannot support a case insensitive match
end

Person.create!(name: 'Bill', ssn: '123456789')
Person.create!(name: 'Ted', ssn: '123456789') #=> fails with uniqueness error

Known Limitations

  • Single cipher for all encrypted fields
  • Currently can encrypt these Mongoid types
    • Date
    • DateTime
    • Hash
    • String
    • Time
  • The uniqueness validator for encrypted fields is always case-sensitive. Using it with case-sensitive false raises an exception.

(c) 2012 Koan Health. See LICENSE.txt for further details.