RubyDES is a full Ruby implementation of the Data Encryption Standard. The purpose of this project was to allow Ruby programmers interested in cryptography a glimpse of how a robust cryptographic algorithm functions in a language they understand.
The best way to understand the RubyDES source code is by following along with a FIPS 46, which you can find at http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf
NOTE: DES is deprecated, and as such, you should not use this implementation in any project you are developing. I highly recommend the AES, TwoFish or Serpent algorithms through the OpenSSL library instead.
Using RubyDES is pretty easy. First, construct a new data and key block.
data = RubyDES::Block.new('mysecret')
key = RubyDES::Block.new('hushhush')
Then, build a new RubyDES::Ctx object and supply the data and key block.
des = RubyDES::Ctx.new(data, key)
Finally, let it go.
encrypted_data = des.encrypt
You will then be returned a DES encrypted block that is completely secure against eavesdropping (if it were still 1997).
To decrypt an encrypted data block, just build a new RubyDES::Ctx object in similar
fashion as before.
un_des = RubyDES::Ctx.new(encrypted_data, key)
And run the DES with the key schedule reversed.
decrypted_data = un_des.decrypt
You can then check to see if it all worked.
data.bit_array.eql?(decrypted_data.bit_array)
Enjoy!
If you have any questions, comments or just want to talk shop about crypto, feel free to reach me through my website at http://www.robertsosinski.com.