A library for storing encrypted data in Mongo
Latest commit e6efabb Sep 13, 2016 @jerryclinesmith jerryclinesmith Prep release 1.3.5



Build Status Code Climate Coverage Status Dependency Status

New Maintainer Needed

We are actively seeking a new maintainer for this gem! As we no longer use MongoDB as part of our platform, we aren't using the gem for ourselves. As MongoDB and Mongoid continually change, we want to make sure our gem keeps up.

If you're interested, please contact us! Thanks


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.


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


gem 'mongoid-encrypted-fields'


  • 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
  • The field getter returns the unencrypted value: Ruby 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): Ruby 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
    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.

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