TLDR: Rails 7 Active Record Encryption

PII (personal identifiable information) and PHI (personal health information) is considered very sensitive, and if you are processing it, there can be requirements to protect it.

Rails 7 added Active Record Encryption, that replaces gems like attr_encrypted. It is a long-awaited default feature by organizations that have high data-security standarts and requirements.

Why you need attribute encryption:

• If someone steals your database dump, they won’t have easy access to the encrypted attributes (they will also need the encryption keys)
• Encrypted columns are automatically filtered in logs

Security-oriented static code analysis tools like bearer/bearer can hint on what attributes you should encrypt:

1. Encrypt attributes

If you run this command in the console

bin/rails db:encryption:init

it will generate a few lines, that you should add to credentials.yml:

active_record_encryption:
  primary_key: 1qRx9LKs1ON5gbk0q5Affs898O0S0sXo
  deterministic_key: pCgz9AgTkwO8zcn3hrZBL6tbNVQyxGvL
  key_derivation_salt: pOIy8FEWO3hVpt1f05LKuWETU1uOICPb

Try to encrypt attributes:

# app/models/client.rb
class Client < ApplicationRecord
  encrypts :name, deterministic: true, downcase: true # string
  encrypts :annual_income # integer
  encrypts :date_of_birth # datetime
  encrypts :health_condition # text
  has_rich_text :description, encrypted: true # ActionText
end

2. Problems that you will encounter:

2.1. Encryptable data types:

You can really encrypt only string and text fields (because we store a long hashed string on the database level).

It is recommended to store encryptable attributes as text, not string.

If you want to encrypt an integer or datetime, you will get errors. You have to store encryptable data as text.

I think it is quite safe to change column type from integer to text. If you do so, further encryption will be easy.

class StoreIntegersAsText < ActiveRecord::Migration[7.0]
  def change
    change_column :clients, :annual_income, :text
  end
end

2.2. Querying encrypted data:

Only if you use deterministic encryption, you will be able to query the database, but only for an exact match like Client.find_by(username: 'yarotheslav').

2.3. Encrypting existing data

If you want to add encryption to existing attributes that already store data, you will get an error.

Add these lines to application.rb to allow encrypted and unencrypted data to co-exist:

# config/application.rb
  config.active_record.encryption.support_unencrypted_data = true
  config.active_record.encryption.extend_queries = true

3. Useful commands

client = Client.last
# encrypt all attributes that use encrypts
client.encrypt
# decrypt all attributes that use encrypts
client.decrypt
# get the value that is stored in the database, not the decrypted version
client.ciphertext_for :sexual_orientation
# is this attribute encrypted?
client.encrypted_attribute? :sexual_orientation
# encrypt all records
Client.all.map(&:encrypt)
# decrypt all records
Client.all.map(&:decrypt)

Example:

Summary:

• Encrypting attributes adds a layer of complexity, but sometimes external factors force you to do it.
• I currently use Active Record Encryption to encrypt ApiToken.secret_token in an app.