@Article{LRW11,
  author = 	 { Moses Liskov and Ronald L. Rivest and David Wagner },
  title = 	 { Tweakable Block Ciphers },
  pages = 	 { 588--613 },
  doi =          { 10.1007/s00145-010-9073-y },                  
  url =          { http://www.springerlink.com/content/c4176k3475ur5310/fulltext.pdf },                  
  journal = 	 { Journal of Cryptology },
  issn =         { 0933-2790 },                  
  date =         { 2011 },                  
  OPTyear = 	 { 2011 },
  volume = 	 { 24 },
  number = 	 { 3 },
  keywords =     { Block ciphers, Tweakable block ciphers, Initialization vector, Modes of
                   operation, Pseudorandomness },
  abstract =     { 
        A common trend in applications of block ciphers over the past decades has
        been to employ block ciphers as one piece of a ``mode of operation''---possibly, a way
        to make a secure symmetric-key cryptosystem, but more generally, any cryptographic
        application. Most of the time, these modes of operation use a wide variety of techniques
        to achieve a subgoal necessary for their main goal: instantiation of ``essentially
        different'' instances of the block cipher.
        \par                  
        We formalize a cryptographic primitive, the ``tweakable block cipher.'' Such a cipher
        has not only the usual inputs---message and cryptographic key---but also a third input,
        the ``tweak.''  The tweak serves much the same purpose that an initialization vector does
        for CBC mode or that a nonce does for OCB mode. Our abstraction brings this feature
        down to the primitive block-cipher level, instead of incorporating it only at the higher
        modes-of-operation levels. We suggest that (1) tweakable block ciphers are easy to
        design, (2) the extra cost of making a block cipher ``tweakable'' is small, and (3) it is
        easier to design and prove the security of applications of block ciphers that need this
        variability using tweakable block ciphers.
                  },
}