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Welcome!
My name is Markus Günther Kuhn (rhymes with moon).
digital signal processing, advanced video and audio technology, data
compression
international standardization
embedded systems
neural physiology
Some of my special skills and fields of knowledge include pay-TV
conditional access systems, compromising emanations (Tempest), VLSI
reverse engineering, tamper resistance, smartcard systems, analyzing
security systems, UNIX system administration,
POSIX/C/Perl system programming, textual-image compression,
bus-encryption processors, high precision timekeeping, timezone and
calendar algorithms, real-time programming, information and coding
theory, modem technology, character sets, Unicode, microcontrollers, efficient algorithms and data
structures, neural networks, and a few other topics about which I publish and provide consulting services occasionally.
Apart from this stuff, I enjoy music, reading, bike riding,
juggling, dancing, movies, sci-fi, astronomy, Wikipedia, BBC Radio 4,
apfelschorle, self-made sourdough bread, unsolved problems and
discussions with interesting people.
Local undergraduate computer science students looking for a
dissertation topic and supervisor might want to have a look at some of
my project ideas.
Contact details
Markus Kuhn
University of Cambridge
Computer Laboratory
15 JJ Thomson Avenue
Cambridge CB3 0FD
United Kingdom
Phone: +44 1223 3-34676
Fax: +44 1223 3-34678
Email: mgk25 at cl.cam.ac.uk (checked several times per fortnight)
Local time = UTC in winter
UTC + 1h in summer (last Sun Mar – last Sun Oct)
Reachability status: Away 27 August to 12 September, no regular email contact.
If you want to send me files: Preferably don't. I
strongly prefer URLs over file attachments. If you must, preferred
file formats include plain text (ASCII or UTF-8), PDF, PostScript, as well as files
packed with tar, gzip, bzip2, zip, and everything else for which
tools are freely available as open source code. My preferred text
processors are LaTeX and
OpenOffice. Microsoft Office
files are also acceptable, but far less convenient. Documents should
preferably be formatted for standard A4
paper.
If you don’t receive an email reply: Sorry.
Internet email is not what it used to be. After more than 15 years, I
am rapidly losing interest in the medium. I no longer spend more than
60 minutes each day replying to email, and in that time, I can usually
only pick messages that can be answered very quickly or that are
directly related to projects that I am currently working on. Thanks to
spam, worms and other people’s misconfigured virus scanners, I receive
often hundreds of messages per day. Various very aggressive filter
mechanisms in my email setup now delay or eliminate unsolicited
messages from outside cam.ac.uk automatically. BCC’ed
messages will be sorted out as spam, as will HTML-only messages that are not
accompanied by a plain text version. If I don’t reply to your message
within three working days, chances are that it got lost in the pile.
Try again or try another medium (phone, visit) if it was important to
you. I never send out automatic “vacation” replies. Check this page
for my reachability status.
Publications
Academic publications
Some selected papers:
An RFID Distance Bounding Protocol
appeared at IEEE SecureComm 2005 in Athens. It describes an alternative
to the classic Brands/Chaum approach, with some performance benefits
for ultra-wideband RFID applications.
An Asymmetric Security Mechanism for
Navigation Signals appeared in the 2004 Information Hiding
Workshop proceedings (Springer-Verlag, LNCS
3200). It proposes a broadcast authentication technique for
navigation signals (GPS, Galileo, Loran-C, etc.), which protects
not only the integrity of the transmitted data, but also its
nanosecond-resolution arrival time, and therefore the actual
positioning result. In other words, it introduces an efficient
and effective digital-signing technique for GPS-style signals
that will makes it practical to offer civilian users a level of
security currently only available to the military. (slides)
Optical Time-Domain
Eavesdropping Risks of CRT Displays appeared in the
Proceedings of the 2002 IEEE Symposium on Security and Privacy,
Berkeley, California, 12–15 May 2002 and extends the concept of
TEMPEST eavesdropping to the optical band by demonstrating that
the image displayed on a CRT can be reconstructed from diffusely
reflected monitor light. (FAQ)
Electromagnetic Eavesdropping
Risks of Flat-Panel Displays appeared in the 4th Workshop on
Privacy Enhancing Technologies proceedings (Springer-Verlag, LNCS
3424). It demonstrates that flat-panel displays with digital
interface cables, including those in many laptops, can pose at
least as much of an eavesdropping risk as CRTs. It also
introduces a very effective new software-based protection
technique. (slides)
Effective scientific electronic
publishing contains a number of tips for preparing online
papers, mostly intended for our local research group, but
probably useful for others as well who want to generate nice PDF
files with LaTeX.
I have a long-standing interest in the international
standardization of technical conventions. The habit of doing
things differently than the rest of the world can be a source of
great annoyance, especially on the Internet. I wrote a few
tutorials on areas that I feel particularly passionate about,
some of which have become widely-quoted references over the
years:
International standard paper
sizes explains the A4 format used today
everywhere outside North America. I dearly wish
folks in the U.S. gave up their strange “Letter” format,
which only causes headaches all over the planet for users
of word processors, laser printers, and copying
machines.
OTPW is my one-time password package for
POSIX systems, optimized for being used with printed password
lists and designed to be more robust against certain
denial-of-service attacks than various older schemes.
JBIG-KIT is my portable C implementation
of a highly effective lossless bi-level image compression
algorithm based on context sensitive arithmetic coding. The JBIG algorithm (specified in
ITU-T Recommendation T.82) implemented in this library is
especially suitable for compressing scanned documents and fax
pages. You can also download the (German) project report (Studienarbeit) that I
wrote about JBIG-KIT (abstract).
In early 1997, I wrote StirMark, a
robustness testing tool for steganographic watermarking
algorithms of still images. It is now maintained by Fabien
Petitcolas.
Older material previously found here is now in my home page attic.
Please do not copy any of my web pages onto your own
Internet server for public access without my explicit permission. If
you want to refer to any of my texts, please use a hyperlink to my
original and not a copy. I update some of the texts frequently and I
want to prevent the confusion that arises if people read somewhere
else obsolete versions that are not under my control. You can view PDF
files using, for instance, Adobe
Reader.