Appeal 2006-2107
Application 09/969,833
3. A one-way function is a function f for which one can compute
the value y=f(x) given the value x, but for which it is computationally
infeasible to compute the value x given y, unless a so-called “trap door” is
known, where only particular one-way functions have trap doors. In the
above context, the value x is called the pre-image of y, and the value y is
called the image of x, both relative to the function f. (Specification 1:18-22).
4. The term “one-way function” as used by Appellant is intended
to include, by way of example and without limitation, any function for
which it is substantially more efficient to compute images from pre-images,
than it is to compute pre-images from images, e.g., a function for which
inversion is computationally expensive, infeasible or otherwise difficult to
achieve. (Specification 6:11-14).
5. The term “chain” as used by Appellant is intended to be
construed generally so as to include not only linear sequences of values, but
also tree or graph structures having multiple branches, each of which may
itself correspond to a linear sequence of values. (Specification 6:15-17).
6. The term “one-way chain” refers to a chain in which at least
one pair of values are related to one another via a one-way function.
(Specification 6:18-19).
7. A so-called one-way chain is a sequence of values v1 . . . vs such
that vi-1=f(vi). More generally, vi-1=f(g(vi)), where g is a function that maps
input of the size of the output of a hash chain or other one-way function h to
the size of the input of the function h. In particular, g could be a truncation
of information to the right length, a padding of information to the right
length, or other similar mapping function, as is well known to those skilled
in the art. It is also known that if h is a function that accepts input of
arbitrary length, as hash functions do, then there is no need to use the
4
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: September 9, 2013