Integer Obfuscator

This is a tool for obfuscating 32-bits integers. More specifically, IntegerObfuscator will one-to-one transform a 32-bit integer to another 32-bit integer using a 32-bit block cipher based on SKIPJACK.

This is useful when you want to transform sequentially generated IDs (e.g. database IDs) into integers that don't have an obvious ordering.

Installation

gem install integer-obfuscator

Example

require 'rubygems'
require 'integer_obfuscator'

c = IntegerObfuscator.new("my secret key")
c.obfuscate(1)            # => 418026769
c.obfuscate(2)            # => 1524067781
c.obfuscate(3)            # => 1476269236
c.unobfuscate(418026769)  # => 1
c.unobfuscate(1524067781) # => 2
c.unobfuscate(1476269236) # => 3

Warnings

This code...

1. is not intended to be cryptographically secure.
2. is slow (i.e., pure Ruby implementation).
3. only handles integers up to 32-bits in size.

References

This is based directly on the Perl Crypt::Skip32 module and the Greg Rose's original C implementation.

• http://search.cpan.org/~esh/Crypt-Skip32-0.15/lib/Crypt/Skip32.pm
• http://www.qualcomm.com.au/PublicationsDocs/skip32.c

Copyright and License

Copyright (c) 2010-2011 Pat Deegan, PhD & Associates, LLC. Released under the MIT license. See the license file for details.