Contents |
Course Title
Stream Ciphers
Course Code
IAM 502
Credit
(3-0)3
Prerequisites
Consent of the instructor.
Content
Linear Feedback Shift Registers: Generating Functions, Minimal Polynomial and Families of Recurring Sequences, Characterizations and Properties of Linear Recurring Sequences. Nonlinear Filtering Functions, Nonlinear Combiners. Design and Analysis of Stream Ciphers: Stream Ciphers Using LFSRs. Non-Linear- Feedback Shift Registers. Cascading Multiple Stream Ciphers, Generating Multiple Streams from a Single Pseudo-Random-Sequence Generator.
Aims
The primary focus of this course will be on the constructions of various cryptographic objects, such as Linear feed back shift registers, Stream ciphers, pseudo random sequence generators, nonlinear feedback shift registers, and others. The course will cover also what security properties are desirable in such objects, how to properly define these properties and how to design objects that satisfy them. This course also serves as an introduction for students who are interested in pursuing research in cryptography.
Learning Outcomes
This is one of the core courses of the Cryptography Program at IAM introducing Stream Ciphers. A stream cipher is a type of private key encryption algorithm. Stream ciphers can be designed to be very fast compared to block ciphers. Block ciphers operate on large blocks of data, whereas a stream cipher typically operates on single bits. With a stream cipher, the transformation of plaintext units varies, depending on when they are encountered during the encryption process. A stream cipher generates a sequence of bits used as a key and encryption is accomplished by combining these bits with the plaintext. This course will attempt to cover the various kinds of building blocks of stream ciphers, and a variety of mathematical tools that can be used to design such ciphers. After taking the course, the students should have an overview of stream ciphers. In industry, they should be able to carefully choose and design a security scheme for a given application.
Suggested Textbooks
- R. Lidl and H. Niederreither, Introduction to Finite Fields and Their Applications, Cambridge Univ. Press, 1986.
- S.W.Golomb: Shift Register Sequences. Aegean Park Press, 1982
- M.J.B.Robshaw: Stream Ciphers. Technical Report TR-701, 2.0, RSA Laboratories, July 1995.
Outline
- WEEKS 1-2: Linear feedback shift registers. Generating functions, minimal polynomial and families of recurring sequences, characterizations and properties of linear recurring sequences.
- WEEK 3: Stream Ciphers and Pseudo Random Numbers. Pseudo random sequences, Linear Congruential Generators, Cryptographic Generators, Design of Stream Cipher, One Time Pad
- WEEK 4: Stream ciphers using LFSRs, additive generators.
- WEEKS 5-6: Non-linear Filtering Functions
- WEEK 7-9: Non-linear Combiners
- WEEKS 10-11: Non-linear Feedback Shift Registers
- WEEKS 12-13: Cascading Multiple Stream Ciphers
- WEEK 14: Generating Multiple Key Streams from a Single Pseudo-Random-Sequence Generator
Resources
- Alfred J. Menezes, Paul C. van Oorschot and Scott A. Vanstone: Handbook of Applied Cryptography. CRC Press, 1996.
- H.C.A van Tilborg. An Introduction to Cryptology. Kluwer Academic Publisher, Boston, 1988.
- William Stallings: Cryptography and Network Security: Principles and Practice. Second Edition
- R. Lidl and H. Niederreither, Introduction to Finite Fields and Their Applications, Cambridge Univ. Press, 1986.