lockbox_repro.rb

require "bundler/inline"

gemfile do
  source "https://rubygems.org"

  gem "activerecord", require: "active_record"
  gem "sqlite3"
  gem "lockbox", git: "https://github.com/ankane/lockbox.git"
end

puts "Lockbox version: #{Lockbox::VERSION}"

Lockbox.master_key = "0"*64

ActiveRecord::Base.establish_connection adapter: "sqlite3", database: ":memory:"

ActiveRecord::Schema.define do
  create_table :users do |t|
    t.text :email_ciphertext
  end
end

class User < ActiveRecord::Base
  has_encrypted :email
end

user = User.create!(email: "[email protected]")
p user.email