gistfile1.rb

# For the queasy, this is MIT licensed. See comment at the end.

module MySQLEncryption
  # Mimics MySQL's AES_ENCRYPT() and AES_DECRYPT() encryption functions

  def mysql_encrypt(s, key)
    encrypt(s, mysql_key(key))
  end
  
  def mysql_decrypt(s, key)
    decrypt(s, mysql_key(key))
  end
  
  protected
  def aes(m,k,t)
    (aes = OpenSSL::Cipher::AES128.new("ECB").send(m)).key = k
    aes.update(t) << aes.final
  end

  def encrypt(text, key)
    aes(:encrypt, key, text)
  end

  def decrypt(text, key)
    aes(:decrypt, key, text)
  end

  def mysql_key(key)
     final_key = "\0" * 16
     key.length.times do |i|
       final_key[i%16] ^= key[i]
     end
     final_key
  end
end

=begin
Copyright (c) 2009 Felipe Coury
 
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
 
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
=end

For this to work in Ruby 2.0 you need to change the mysql_key method as follows:

def mysql_key(key)
  final_key = "\0" * 16
  key.length.times do |i|
    final_key[i%16] = (final_key[i%16].ord ^ key[i].ord).chr
  end
  final_key
end

This is due to the changes to how strings handle encoding etc. Enjoy 😄

The change above is also required for Ruby 1.9.3 and possibly 1.9+

andypike, thanks a bunch - was trying to get this to work in 2.x for a while without much luck.

Thanks.