TCS / Studies / T-79.159 Cryptography and Data Security
Helsinki University of Technology, 
     Laboratory for Theoretical Computer Science

T-79.159 Cryptography and Data Security (3 cr)

Spring 2004

[General Information] [Lectures] [Tutorials] [Other Interesting Stuff] [TOPI]

News: Exam results and grading can now be found below.

News: since one tutorial (and lecture) was cancelled, we decided to only require 5 tutorials out of 10.

News: To prepare for exams, you might want to check the exam questions from the previous year (exam on 10.12.03.)

News: second exam time added (17th May). (15.04.04)

This is an introductory course on cryptology and data security. We plan to teach the course according to textbook, and our preliminary plan is to cover the first 12 chapters, and spend the last few lectures for "new and recent" material. It is also possible that we will have some famous cryptographer giving a minicourse in May. (In 2002, it was Phil Rogaway, in 2003, it was Vincent Rijmen.)

General Information

  • Lectures by Prof. Helger Lipmaa: Wednesday 16-18, room/hall T2 Exercises: Thursday 14-16, T3. The first lecture is on Jan 21st
  • Exercises by Markku-Juhani O. Saarinen. Time:
         Thursdays, 14-16, room T3
    The first tutorial is on Jan 29th
  • Course material:

    The 2003 course had the next textbook: Network Security: Private Communication in a Public World" (2nd edition) by Charlie Kaufman, Radia Perlman, Mike Speciner, Charles Kaufman, Mike Spiciner. However, I was unhappy with this textbook so we will drop it. The lectures will stay almost the same (if you want, you may browse through the slides of Spring 2003; thus also this book will be helpful during the first 7 lectures or so) with some added material and some restructuring.

  • In order to pass the course one has to
    • complete (in a timely manner) 5 of the 10 tutorials
    • pass the exam (with a grade greater than 0)
  • Newsgroup: opinnot.tik.salaus
  • First exam: 12.05.2004, 16-19, in T1.
  • Second exam: 17.05.2004, 9-12, T1. NEW (15.04.04)

    General exam URL (Register at webtopi)

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If you have not done so yet, please take the course Mat-1.128 Discrete Mathematics during Spring 2004. This will be mandatory. We will assume that you have taken the course, since any course on cryptography requires the knowledge of main results from this course. The only exception is made to the students who will be at the HUT for their last study year, for whom T-79.159 is mandatory, and who have not taken Mat-1.128 yet. Such individuals please contact the responsible teacher before 22.01.2004 by email, stating all relevant information --- your wish may be granted. For you it is possible to take Mat-1.128 in parallel, since it runs this spring.

Lecture Notes

(Slides in English; Postscript and/or PDF; future lectures without slides may change; new slides will appear here asap; consulting 2003 slides is highly recommended)

Lecture 1: Introduction to Cryptography -- 21.01.2004
Practical information about the course.
Lecture 2: Secret-key cryptography -- 28.01.2004
Lecture 3: Modes of Operation -- 04.02.2004
Lecture 4: Hash Functions -- 11.02.2004 (by MJOS) Why birthday paradox works ? (pdf).
Lecture 5 on 18.02.2004 is CANCELLED!
Lecture 5: Public-key algorithms -- 25.02.2004
Lecture 6: Cryptanalysis of public-key algorithms -- 03.03.2004 (by MJOS)
Lecture 7: Authentication -- 10.03.2004
Lecture 8: Zero-knowledge and commitments -- 17.03.2004.
Slides corrected on Mar 23 (Added slide 12, noted in slide 13 that x is in QNR(n))
Lecture 9: Secret sharing, threshold encryption, MPC -- 24.03.2004
24th slide corrected on May 24 04 (replaced an a. with a mu)
Lecture 10: Pseudo-randomness, provable security -- 31.03.2004
Lecture 11: Electronic Cash and Oblivious Transfer -- 07.04.2004
(No lecture on 14.04.2004 due to Easter holidays)
No lecture on 21.04.2004 due to the simultanous security workshop in Otaniemi. All students are encouraged to attend. See for more information.
Lecture 12: Epilogue -- 28.04.2004
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Tutorial exercises and solutions

(in English, PDF format)
Tutorial 1. (due 29.01.2004)
Tutorial 2. (due 05.02.2004)
Tutorial 3. (due 12.02.2004)
Tutorial 4. (due 19.02.2004) Tutorial 4 has been postponed to 26.2.2004. Here's my solution.
Tutorial 5. (due 04.03.2004)
Tutorial 6. (due 11.03.2004)
Tutorial 7. (due 18.03.2004)
Tutorial 8. (due 25.03.2004)
Tutorial 9. (due 01.04.2004)
No tutorial on 08.04.2004 due to Easter holidays.
Tutorial 10. (due 15.04.2004)

Exercise session corresponding to lecture number X will be held 8 days after the lecture (i.e., Thursday the next week). The corresponding tutorial will be published not later than on Monday. It will be verified during the exercise session how many students have done the homework. (It will not be possible to submit the tutorial later!) It will be necessary to pass 5 of the 10 tutorials to get to the exam. (Not 6 from 11 as announced initially.)

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Tutorial results

The following students have passed the tutorial requirements and are free to participate in the exam:

39125e 41617k 43111a 43153e 43473b 44027e 45344m 45387t 45407u 46573e 
46628c 46929w 47385w 47961f 48344k 49460d 49486m 49524m 49547s 49580l
49937f 51098j 51680a 52829l 52874u 52891s 52925? 52926? 52933w 54503n 
55347a 55476t 55620j 57264v 57796v 59218s 59736a 60028j 60042c 60058w 
60113u 62247d 62830u 63874t 64018j 64022n 64139s 64204d 75016e 75024p

Following students have only participated in <5 of the tutorials. Please contact me (mjos) if you feel that there's a mistake in this list - typos are easy to make when entering the handwritten sheets..

Code    Which tutorials
------  ----------------
45735c  1 2
46929w	5
51474d	2
53153e	1 7
54134d	4
55218s	1 8

-- mjos

Exam results!

Please contact Markku-Juhani O. Saarinen (, if you wish to discuss grading, or come to see me at B254 on June 3, 2004 between 14:00 and 16:00.

        Final Exam -- May 12,2004 at 16--19 at hall T1
        T-79.159 Cryptography and Data Security
        (All have passed the tutorials.)
        Student Points  Grade
        39125E  14      1 (*)
        43473B  0       0 fail
        48344K  19      3
        49580L  1       0 fail
        52874U  25      4
        60028J  29      5
        60042C  14      1
        60058W  9       0 fail
        62247D  22      3
        62830U  9       0 fail (*)

        (*) These students re-took the exam on 17.5. and obtained
            higher grades.
        Grading (6 points max for each one of the 5 questions):
        Points  Grade
        11..14  1
        15..18  2
        19..22  3
        23..26  4
        27..30  5


        Final Exam -- May 17,2004 at 9--12 at hall T1
        T-79.159 Cryptography and Data Security

        (All have passed the tutorials.)
        Student Points  Grade
        39125E  21      3
        44027E  17      2
        45344M  17      2
        45387T  13      1
        45407U  22      3
        46573E  17      2
        49460D  19      3
        49547S  21      3
        49937F  29      5
        51680A  9       0 fail
        52891S  19      3
        52925M  11      1
        52926N  10      0 fail
        54503N  16      2
        55620J  15      2
        59218S  19      3
        59736A  5       0 fail
        62830U  21      3
        64022N  17      2
        64139S3 17      2

        Grading (6 points max for each one of the 5 questions):
        Points  Grade
        11..14  1
        15..18  2
        19..22  3
        23..26  4
        27..30  5

Other Interesting Stuff

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