@Misc{Riv98d,
  author = 	 { Ronald L. Rivest },
  title = 	 { Block encryption algorithm with data-dependent rotations },
  howpublished = { U.S. Patent 5,724,428.  Issued March 3, 1998. },
  date =         { 1998-03-03 },                  
  OPTyear = 	 { 1998 },
  OPTmonth = 	 { March 3, },
  urla =         { <a href="http://www.google.com/patents/US5724428">google-patent-page</a> },                  
  abstract =     { 
                  A simple encryption and decryption device has been
                  developed. The underlying algorithm is a fast block
                  cipher that may be implemented efficiently in
                  hardware or software. The algorithm makes heavy use
                  of data-dependent rotations. The amount of each
                  rotation depends on the data being encrypted and
                  intermediate encryption results. The variables for
                  the algorithm include word size, rounds, and the
                  length of a secret key.  
                 },                  
}