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Research
Information is recognized by many organizations as an important asset. Few
businesses could function effectively without the ability to rely to some
extent on information as a resource. Information security is concerned with
providing assurances about the security and authenticity of data, and is of
strategic importance to todays world of open networks and electronic data.
Privacy is a growing issue in the area of both wired and wireless
technology. Consumers are becoming increasingly aware of their privacy
rights and needs, and are demanding the ability to control the use of their
data. In practice, privacy can be provided by a combination of legislative,
policy, and technological means. This project has two main themes. The
first is the exploration, together with representatives from industry and
provincial and federal government agencies, of policy and technological
aspects of privacy. The second is the design and analysis of
number-theoretic solutions for solving problems involving privacy and
information security.
1. Privacy.
In the past few years, those involved in developing and implementing
technology have experienced a growing awareness of privacy risks within
those technologies and a better understanding of privacy-averse
environments. This awareness has brought to the fore the need to develop
and implement further technologies that are privacy protective. Parallel to
this, around the globe, economic crime units and law enforcement agencies,
governments, businesses and lawyers wrestle with the tools to combat the
international specter of cyber crime and terrorism, while often sidelining
key privacy issues. The exploration of privacy and security issues is
fundamental to understanding how the construction and implementation of
privacy policies and technologies can be improved for the real world. We
will explore these and other privacy and security issues through a series
of workshops designed to maximize interaction between key representatives
from industry, academia, and government.
2. Number-Theoretic Cryptography.
The security of most public-key
cryptographic systems is based on the difficulty of a number-theoretic
problem, such as the integer factorization problem of the discrete
logarithm problem. Cryptosystems based on the difficulty of these problems
are used commercially to secure electronic palyment over the Internet,
stock trading from pagers and cell phones, and multi-applications on smart
cards. We will continue to study important number-theoretic objects used in
public-key cryptography. In particular, this includes elliptic curves,
hyperelliptic curves, cubic curves, quadratic number fields, algebraic
functions fields, finite fields, and integer lattices.
SUB-PROJECTS
1. Elliptic curve cryptography.
We will continue to study the security of the elliptic curve discrete
logarithm problem (ECDLP), the efficiency of
elliptic curve systems, and the design and analysis of elliptic curve
cryptographic protocols. We will also consider the analogues of these
problems to other curves, including hyperelliptic curves, superelliptic
curves, and Cab curves.
2. Cubic function fields.
We intend to focus on developing and
implementing algorithms for computing invariants of cubic function fields
as well as exploring these fields for cryptographic applications. We have
already developed an algorithm for computing the fundamental units and the
regulator of a purely cubic function field of unit rank two. Work on
generalizing ths technique to arbitary cubic fields is in progress. In a
recengly published paper, Dr. Scheidler described a fast arithmetic in the
ideal class group of a purely cubic function. In collaboration with Mark
Bauer of the University of Waterloo, she is currently investigating
improvements in speed to these algorithms, with special emphasis on fields
of low genus, to make them practical for cryptographic purposes.
3. Real quadratic field cryptosystems.
Although function fields as a
basis for cryptography have several advantages over number fields, such as
greater speed and cleaner computer implementation, it should be pointed out
from an algorithmic and cryptographic perspective, they are less well
understood than number fields. We intend to investigate algorithms for
implementing key exchange protocols and for solving the discrete logarithm
problem in real quadratic fields. We will be conducting this research in
several areas: improved implementation, improved algorithm for solving
the DLP, and Benchmarking.
4. Determination of optimal discriminants.
One advantage to using
number fields for cryptographic purposes is that we have some freedom in
selecting a certain parameter, the discriminant. However, this parameter
needs to be chosen optimally with respect to both security and efficiency
of implementation. We are currently developing a low cost, high-speed
special computing device called a number sieve to help determine optimal
selections. In the case of real quadratic fields, attempts by adversaries
to break the corresponding cryptographic scheme can be thwarted by
selecting discriminants that are quadratic nonresidues for many of the
smallest primes. We were able to use the fastest number sieve in existence,
constructed in 1995 at the University of Manitoba, to show that finding
such discriminants can be done very quickly. We are now using more modern
Field Programmable Gate Array (FPGA) technology to build a faster and more
flexible number sieve that can be tailored to a specific sieve problem
instance. Although no hardware development is required for the new sieve,
at least a year of full-time development work remains. The project is a
collaborative effort involving Dr. Hugh Williams, MSc student Kjell
Wooding, and Dr. C. Patterson of Xilinx (Boulder, Colorado).
5. Benchmarking.
We will use a Beowulf cluster built of off-the-shelf
components as the hardware configuration for the testing. A Beowulf cluster
is a collection of individual stand-alone processors connected together so
they can communicate. The servers will be interconnected with standard fast
Ethernet connections and provide the computer power needed for the sieving
part of the DLP algorithm. All software required for the cluster, including
the operating system Linux, is free of charge when used for research
purposes. The cluster is sufficiently flexible that it can be used to test
the effectiveness of many other cryptosystems and can be used well beyond
the lifetime of this project. Dr. Williams successfully applied to the
Alberta Ingenuity Fund for $262,740 to set up this laboratory of high speed
computing devices to test and benchmark cryptographic systems. We have
recently combined this award with Professor Mike Jacobson's $642,000 CFI
award to create a very extensive, powerful and dedicated system, which we
expect to have up and running early in 2003.
6. Unconditional determination of the regulator.
Another important
consideration in our work is the question of whether a given instance of
the DLP is actually solvable, which highlights the problem of testing an
ideal for principality. To do this we need to know the regulator.
Unfortunately, the regulator that the fastest algorithm currently available
determines is conditional on the Generalized Riemann Hypothesis. It is of
great interest to find the regulator unconditionally. The conditional
algorithm should at least compute an integral multiple of the regulator,
and this is something that can be checked very quickly. Having made this
determination, the next problem is to establish that the integral
multiplier of the regulator in the conditional regulator is 1. There are
two phases of doing this. The first is to establish that the regulator must
exceed some predetermined bound. The next is to prove that for no integer
less than a certain amount can we have the regulator being conditional one
divided byshould allow us to compute regulators for fields of perhaps 60 or
65 digit discriminants.
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