script/plugin install git://github.com/handerson/string_encryption.git

Next we need to add an encryption key as the constant ENV['STRING_ENCRYPTION_KEY']. To do this just run

 script/generate encryption_key

ENV['STRING_ENCRYPTION_KEY'] = "somekey"

Now encryption/decryption is easy.

Encryption:

"Test".encrypt  #=> "NDFkZTc5NDEyNTg1MzdiZPzBrxZz5aoN%0A"

"NDFkZTc5NDEyNTg1MzdiZPzBrxZz5aoN%0A".decrypt  #=> "Test"

Code at Github:
http://github.com/handerson/string_encryption

This works in MRI but not in JRuby:

unencrypted_data = "test"

des = OpenSSL::Cipher::Cipher.new("des-ede3-cbc")
des.encrypt
des.key = '0123456789abcdef01234567890'

des.iv = "ed87acdcca419954edccb736f7dc77a74f5ac8dfe3861c3d5f77248e21592131a5423d63ff91f07956ce1aa386f8359931b5" # 100 characters
encrypted_data = des.update(unencrypted_data) + des.final

puts encrypted_data

JRuby gives you this very helpful message:
ruby_string_encryption.rb:27:in `encrypt': No message available (OpenSSL::Cipher::CipherError)
from ruby_string_encryption.rb:37

Change the IV to 8 characters and everything works fine.

Update 10/14/2009 The code that I originally posted was incorrect. I have updated it. Also I opened a ticket for this issue.

If you are looking for what size an initialization vector should be check out my post on encrypting a string with Ruby.

require 'openssl'

KEY = '0123456789abcdef01234567890' # 24 characters

string = "encrypt this"

des = OpenSSL::Cipher::Cipher.new("des-ede3-cbc")
des.encrypt # this tells OpenSSL what mode to operate in, here we want to encrypt data
des.iv = iv = '01234567' # 8 characters, hard-coded for now

data = des.update(string) + des.final  
data = iv + data # this way when we randomize our IV it will be available when we need to decrypt the data

puts data

This should output something like 01234567z4¥K½ß) ©ˆˆ˜ž. This isn’t the friendliest way to send data, so lets do something about that. The easiest thing to do is Base 64 encode the data, and maybe URI escape it for good measure.

# be sure to put the following at the top of your code:
# require "base64"
# require 'uri'
# after 'the puts data' in the snippet above do the following:

data = Base64.encode64(data)
data = URI.escape(data, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))

puts data

This should give you the much nicer MDEyMzQ1Njd6jzSlS73fKSAdqYgRiJie%0A.

Decryption is similarly easy.

des = OpenSSL::Cipher::Cipher.new("des-ede3-cbc")
des.decrypt
des.key = KEY
encrypted_data = URI.unescape(data)
encrypted_data = Base64.decode64(data)
des.iv =  encrypted_data.slice!(0,8) #This gives us our iv back and removes it from the encrypted data
  
decrypted = des.update(encrypted_data) + des.final  
    
puts decrypted

If you are using Rails or have access to ActiveSupport ActiveSupport::SecureRandom is a great way to generate your key and IV. Also be sure to check out ActiveSupport::MessageEncryptor and my string_encryption plugin. I’ll probably do a writeup on the string_encryption plugin sometime next week.

Install Plugin

script/plugin install git://github.com/handerson/data_migration.git

Generate Migration

script/generate data_migration BlockedDomains

exists  db/data
create  db/data/20090915161242_settings.rb

db/data/20090915161242_settings.rb:

class BlockedDomains < ActiveRecord::Migration
  def self.up
  end
end

Add your data:

def self.up
  BlockedEmailDomain.create(:domain => "mailinator.com")
  BlockedEmailDomain.create(:domain => "spamherelots.com")
  BlockedEmailDomain.create(:domain => "disposeamail.com")
end

Run Migration

rake db:data:migrate

==  BlockedDomains: migrating ===========================================================
==  BlockedDomains: migrated (0.0020s) ==================================================

db:data:migrate adds the data migration version number to the ‘schema_migrations’ table so it will not be ran again.

Code at Github:
http://github.com/handerson/data_migration