Cryptography

Summer Term 2012

Lecturer

Teaching Assistants

Fabian Bendun
Sebastian Meiser

Tutors

Jan Balzer
David Pfaff
Maximilian Harz
Iulia Bolosteanu
Milivoj Simeonovski

Lecture Time

Mon, 10 - 12; Thu 14-16

Office Hours (TAs)

Mon 14-15; Mon 16-17; Fri 11-12 (E1.1, Room 2.18)

Location

E2.2 (Günter Hotz lecture hall)

Language

English

Content

Introduction to Modern Cryptography

Registration

Closed

Contact

crypto12-admin@mail-infsec.cs.

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uni

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Latest News

2012/05/16: Registraction closed.
2012/05/08: The lecture of Thursday the 10th May takes place in lecture hall 1 of buildingE2.5.
2012/02/01: Registration is now open.
2012/01/13: the website is online.

Description

This course is an introduction to modern cryptography. It will introduce cryptography from scratch. No previous knowledge in cryptography or computer security is required. The list of topics comprises:

Information-theoretic security and the One-time Pad
Symmetric encryption, stream ciphers, block ciphers, Data Encryption Standard (DES), Advanced Encryption Standard (AES)
Asymmetric encryption, cryptosystems based on RSA and on the discrete logarithm problem, Cramer-Shoup encryption
Digital signature schemes
Cryptographic hash functions
Selected cryptographic protocols and their security
Crypto in the "real world"
Basic concepts of advanced cryptographic primitives and current research topics: Bit commitment, zero-knowledge proofs, simulatability, linking formal verification and cryptography

Most of these topics are covered by the following books, all of them are available in the computer science library.

Jonathan Katz, Yehuda Lindell: Introduction to Modern Cryptography. Chapman & Hall/Crc, 2008
Douglas R. Stinson: Cryptography: Theory and Practice. CRC Press, 2005
Nigel Smart: Cryptography: An Introduction. McGraw-Hill, 2003

Prerequisites

This course is a core theory lecture. Basic knowledge in computability, complexity theory, and number theory is useful, but not utterly necessary, as it can be acquired during the course.

Tutorials

There will be weekly tutorials every tuesday in between 2pm and 6pm.

2	Tue, 14-16	E1.3, SR014 (map)	David Pfaff
3	Tue, 14-16	E1.3, SR015 (map)	Maximilian Harz
4	Tue, 14-16	E1.3, SR016 (map)	Iulia Bolosteanu
1	Tue, 16-18	E1.3, SR014 (map)	Jan Balzer
5	Tue, 16-18	E1.3, SR015 (map)	Maximilian Harz
6	Tue, 16-18	E1.3, SR016 (map)	Milivoj Simeonovski

Why are all tutorials at the same day?
See section on quizzes below.

Michael Backes will be available for your questions on Friday, 13-14.
Office: building E1.1, room 211.

Sebastian Meiser and Fabian Bendun will be available for your questions whenever their door is open.
Office: building E1.1, room 215.

There will be office hours, where the tutors will be available for your questions, at the following times in building E1.1, room 218:

Mon, 14:00 to 15:00
Mon, 16:00 to 17:00
Fri, 11:00 to 12:00

Homeworks

Weekly homework exercises will be handed out and (posted here) after the lecture on Thursday. Their solutions will be discussed in the exercise groups 5 days later, on Tuesday, as well as posted here afterwards. No homeworks have to be submitted, but you are encouraged to ask any question you might have concerning the course in the office hours. Homework exercises will thus not influence your grade, however, by presenting solutions in the tutorials you may gain a better grading in the quiz, see below.

Weekly Quiz

Each tutorial starts with a short (approx. 15 minutes) quiz covering the topics of the same lectures that were addressed in the corresponding homework assignment. Your overall quiz-grade is determined by dropping the quiz with the lowest grading, and calculating the average of the remaining quizzes.

You can further improve your quiz-grade by a "good presentation" of your solutions of the homework exercises in the tutorials. In this case, you may drop another quiz, i.e., at most two quizzes may be dropped. Please be aware that there is a limited number of exercises, and if more than one student opts for one particular solution, a random student will be drawn. So start early enough!

Quizzes will affect your final grading by 30%, and you need an overall quiz-grading of at least 50% to pass the course.

Exams

There will be two mandatory exams: A mid-term exam, and a final exam.

The mid-term exam will be approx. one hour and consist of multiple-choice and simple questions intended to test your basic understanding of the course material covered so far. Your mid-term grade will affect your final grading by 20%, however, there is no lower bound that has to be reached in order to pass the course.

The final exam will be a written test of two hours. It will make up 50% of your final grade, you need at least 50% to pass the course.

Grading & Requirements for Passing the Course

Let Q be your quiz score, M your score in the mid-term exam, E your score in the final exam, and B your score in the backup exam, each in percent. Then your final overall score Final is calculated as

Final = 0.3*Q + 0.2*M + 0.5*Max(E,B)

You pass the course if

Q ≥ 50% and Max(E,B) ≥ 50% and Final ≥ 50%

Q: I got only 49% in the quizzes, but 100% in both exams, will I pass?
A: No, you need 50% in your quizzes to pass.

Q: I got only 49% in the final exam, but 100% in the quizzes and the mid-term exam, will I pass?
A: No, you need 50% in your final exam to pass. Consider participating in the backup exam.

Q: I got only 30% in the mid-term exam, but 100% in final exam and in the quizzes, will I pass?
A: Yes, there is no minimum requirement on the mid-term exam. However, of course, you need a final score of 50% to pass.

Backup Exams

Date and time of the backup exam will be announced. You may take part in the backup exam if you qualified for the final exam, i.e., you got at least 50% score in the quizzes.

The backup exam will be written. Please note that if you have passed the final exam and also take the backup exam, the better score between the two will count for your final grade.

Lecture Overview, Material & Tutorials

#	Date	Topic	Slides	Homework	References
1	2012/04/19	Organizatorial aspects. Historical overview of cryptography. Information theoretic security. Perfect secrecy. One-time pad.	s1 s1(3on1)	hw 01 (sol 01) cipher	Lecture Notes 1-2.3
2	2012/04/23	Stream ciphers, randomness	s2, s2(3on1)		Lecture Notes 2.4
3	2012/04/26	Pseudorandom permutations, pseudorandom functions, switching lemma, modes of operation, 1-CPA	s3, s3(3on1)	hw 02 (sol 02)	Lecture Notes 3.1-3.4
4	2012/04/30	Definitions of security, DES, Feistel networks	s4, s4(3on1)		Lecture Notes 3.5 - 4.2
	2012/05/3	No lecture: canceled		hw 03 (sol 03)
5	2012/05/7	Attacks on DES, AES, Message authentication codes			Lecture Notes 4.3 - 5.2
6	2012/05/10	AES, MACs, Collision resistant hash functions	s6, s6(3on1)	hw 04 (sol 04)	Lecture Notes 5.3 - 5.5
7	2012/05/14	Combining MACs and Encryptions, Basic number theory facts			Lecture Notes 6
	2012/05/17	No lecture: Ascension Day		Homework: Prepare for the exam
	2012/05/21	Midterm Exam
	2012/05/28	No lecture: Whit Monday
8	2012/05/24
9	2012/05/31
10	2012/06/4
	2012/06/7	No lecture: Corpus Christi
11	2012/06/11
12	2012/06/14
13	2012/06/18
14	2012/06/21
15	2012/06/25
16	2012/06/28
17	2012/07/2
18	2012/07/5
19	2012/07/9
20	2012/07/12
21	2012/07/16
22	2012/07/19
23	2012/07/23
	2012/07/26	Question and Answer Session
	2012/08/02	Final Exam

You can also download the lecture notes from the beginning up to the current ones as one file here.

There are the following tutorials:

#	Date	Lectures	Quiz	Comments
I	Tue, 2012-04-24	1	1
2012-05-01	May Day
II	Tue, 2012-05-08	2-4	2
III	Tue, 2012-05-15	5,6	3
Midterm Exam
IV	Tue, 2012-05-22			Discussion on the Midterm Exam
V	Tue, 2012-05-29		4
VI	Tue, 2012-06-05		5
VII	Tue, 2012-06-12		6
VIII	Tue, 2012-06-19		7
IX	Tue, 2012-06-26		8
X	Tue, 2012-07-03		9
XI	Tue, 2012-07-10		10
XII	Tue, 2012-07-17		11
XIII	Tue, 2012-07-24		12
Final Exam

Registration and Mailing List

Registration closed.