[last update: Oct 15,
2008]
This is
the home page of the introductory course in Cryptography intended for second part
students in computer science
and mathematics (and whoever else may be interested).
We cover
some basic concepts and results in theoretical and practical cryptography. The
course will end with student
projects, where students can either do something practical, related e.g. to
programming, or a theoretical study.
Monday 9:15 –
11:00
(Typically preparing exercise from 9:15-10:00 and presenting exercise from
10:15-11:00)
Wednesday 9:15 –
11:00
(Typically lecture)
Lectures and
exercises are in IT-huset-112.
The documentation
will consist of hand-in exercises during the course, and project work plus
presentation of project at the end
of the course.
Approximately 10 hand-in exercises will be given, and you must hand in and have
approved at least 7 of these.
The deadline for
handing in the week’s hand-in is 10:14 Monday.
Here is a list of suggestions
for projects.
A main source will be Stinson's book
"Cryptography, Theory and Practice", THIRD edition.
but in parallel with this, the notes below will play a major role, most
importantly
"Definitions and results for cryptosystems",
"Signature and Authentication systems" and
"Discrete log based cryptosystems".
The slides
I used for the first lecture are available here as pdf file (Updated Aug 27
2008)
WARNING: the versions
posted below are from last year, and may be revised, as we go along.
A note on Modular
arithmetic and groups is available here as pdf
file.
A note on Definitions
and results for cryptosystems and their modes of use is available
here as
pdf file. It covers both conventional and public-key systems.
A note on Discrete
log based cryptosystems. Replaces (most of) Sec 6 of Stinson. Available
here
as pdf
file.
A
corresponding note on results and definitions for Signature and
Authentication Systems is available
here as pdf file.
A note on Key
Management are available here as pdf file.
A note on Secret
Sharing, available here as ps file
More
material will be added here as we move along, in case I have it available
electronically.
Slides
Lecture 1:
Classical Cryptosystems [Lec1.pdf] (Updated
Sep 2 2008)
Lecture 2: Classical Cryptanalysis [Lec2.pdf] (Updated
Sep 3 2008)
Lecture 3: Shannon’s Theory [Lec3.pdf]
(Updated Sep 10 2008)
Lecture 4: Modern Block Ciphers [Lec4.pdf]
(Updated Sep 17 2008)
Lecture 5: AES [Lec5.pdf] (Updated Sep 24
2008)
Background
Material
A paper by Stefan Wolf containing an introduction to information theory and
uncontionally
secure cryptography.
A report
on the Rijndael cipher (chosen as the new AES algorithm), written by the
inventors.
We will be covering
the following main points, although not necessarily in the order listed.
Some of the points mentioned are not covered in the course as such, and may in
stead be used as subjects
for student projects.
·
Introdution to some basic concepts and models
·
A quick look at conventional ciphers,
o AES, DES etc.
o Modern cryptanalysis
· One-way functions,
o
Variants: one-way permutations, trapdoor functions
o
Examples: RSA, Discrete log, etc.
· Secure Public-Key Encryption,
o Passive security definitions
o Example systems
·
The hard-core bit theorem and connections to
encryption
· Chosen ciphertext security,
o Definitions
o Cramer-Shoup system
· Digital Signatures
o
Hash functions, the hash-and-sign paradigm
o Tree-based authentication
· Unconditional Security
o Information theory
o Shannon's perfect security results
o Universal hashing and privacy amplification
o Key exchange over noisy channels
· Key management
o Certificate systems
o Secret Sharing, threshold crypto
Here are some
assorted links to various places of interest:
·
The Cryptology Group at the
·
The home page of IACR,
the International Association for Cryptologic Research. Info on conferences,
journals etc. IACR is behind most worthwhile activities of this sort in the
area.
·
DigiCrime,
where you can have almost any digitial crime committed that your heart desires:
you can ask them to break into other peoples systems, counterfeit electronic
money, etc. Of course it's all a joke, and hilariously funny too, but
with a serious purpose: you can find a seemingly endless list of real-life
security problems and break-in's that really happened. Of course,
DigiCrime were not responsible for those - or so they say...:-)
·
The EPRINT Archive,
nice source of the very latest papers in the area, hosted by IACR (see above)
·
The theory group
at MIT, houses one of the best cryptography research groups in complexity
based cryptography. They also have several nice literature search tools
on-line.
·
The crypto group
at ETH Zurich, the leading research group in information theory based
cryptography.
·
Cryptomathic
· Home page of Mihir Bellare, who is one the well known figures in crypto research. He has one of the most informative personal home pages in the area. Good source of all kinds of links and publications.
·
Helger Lipmaa’s Crypto Pointers. A
great categorized collection of publications on cryptographic research.