@misc{VDTJR15,
  author =    { Marten Van Dijk and Nickolaos Triandopoulos and Ari Juels and
                Ronald Rivest },
  title =     { Forward secure pseudorandom number generation resilient to forward clock attacks },
  howpublished = { U.S. Patent 9,083,515.  Issued July 14, 2015. },
  date =      { 2015-07-14 },
  OPTmonth =  { July 14, },
  OPTyear =   { 2015 },
  urla =      { <a href="http://www.google.com/patents/US9083515">google-patent-page</a> },
  abstract = { Methods and apparatus are provided for generation of
                  forward secure pseudorandom numbers that are
                  resilient to such forward clock attacks. A forward
                  secure pseudorandom number is generated by obtaining
                  a first state si corresponding to a current leaf
                  node vi in a hierarchical tree, wherein the current
                  leaf vi produces a first pseudorandom number ri-1;
                  updating the first state si to a second state si+t
                  corresponding to a second leaf node vi+t; and
                  computing a second pseudorandom number ri+t-1
                  corresponding to the second leaf node vi+t, wherein
                  the second pseudorandom number ri+t-1 is based on a
                  forward clock reset index that identifies an
                  instance of the hierarchical tree, wherein the
                  instance of the hierarchical tree is incremented
                  when one or more criteria indicating a forward clock
                  attack are detected. The forward clock reset index
                  can be encoded in a forward secure manner in the
                  hierarchical tree.  },
}