Cryptography and SecurityAdvanced Cryptography

Serge Vaudenay

ÉCOLE POLYTECHNIQUEFÉDÉRALE DE LAUSANNE

http://lasecwww.epfl.ch/

SV 2010 Advanced Crypto EPFL-SSC 1 / 20

Language?

all provided documents are in English

lectures are in English (ou bien?)

SV 2010 Advanced Crypto EPFL-SSC 2 / 20

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. .1 Chapter 0: Preamble

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. . 1 Chapter 0: PreambleThis CourseAdministrative InformationOther Courses

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Advanced CryptographySerge Vaudenay

continuation of Cryptography and Security

cryptanalysis: weaknesses in some cryptographic schemes

security proof techniques for cryptographic schemes

foundations

more cryptographic schemes: interactive proof

SV 2010 Advanced Crypto EPFL-SSC 5 / 20

Chapters

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. .1 The Cryptographic Zoo

reminders, prerequisites

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2 Cryptanalysis (Public-Key)proof by security reduction, implementation issues (and potentialweaknesses)

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3 Cryptanalysis (Conventional)statistical analysis

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4 The Power of Interactioninteractive proofs and zero-knowledge

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5 Proving Securityrandom oracles, games

SV 2010 Advanced Crypto EPFL-SSC 6 / 20

Goal of the Lecture

to understand why cryptographic schemes work

to understand how their security is grounded

to see the link between cryptography, complexity theory, andalgorithmic number theory

to have fun with nice cryptographic toys

SV 2010 Advanced Crypto EPFL-SSC 7 / 20

Prerequisites

Cryptography and SecuritySerge Vaudenay

SV 2010 Advanced Crypto EPFL-SSC 8 / 20

Some Useful Backgound

algorithmics

notions of probability theory (discrete)

notions of combinatorics

notions of finite fields (algebra)

albegra (group theory)

notions of number theory (arithmetics)

notions of problem reduction (complexity theory)

SV 2010 Advanced Crypto EPFL-SSC 9 / 20

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. . 1 Chapter 0: PreambleThis CourseAdministrative InformationOther Courses

SV 2010 Advanced Crypto EPFL-SSC 10 / 20

Advanced Cryptography v3.2

This lecture has been given since 2000.All comments / suggestions / remarks are valuable

v1: complete lecture on cryptography

v2: split basic/advanced, basic merged with network security

v3 (2008–09): major revision

now in v3:cryptographic analysisfoundations of cryptographyelements of security proof techniques

SV 2010 Advanced Crypto EPFL-SSC 11 / 20

A Classical Introduction to Cryptography

textbook exercise bookhttp://www.vaudenay.ch/crypto/

SV 2010 Advanced Crypto EPFL-SSC 12 / 20

Springer Lecture Notes

Lecture notes published by Springerspecial price (∼CHF 65 instead of > 80) for students at the EPFLbookstore

Exercise book (with solutions) published by Springerspecial price (∼CHF 34 instead of > 45) for students at the EPFLbookstore

warning: lecture notes may not be fully adapted to v3(lecture notes were written at the time of v1 and v2)

some free copies can be found online

SV 2010 Advanced Crypto EPFL-SSC 13 / 20

Further References

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. .1 Stinson. Cryptography, Theory and Practice (3rd Edition). CRC.

2005.Good lecture notes

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2 Menezes-van Oorschot-Vanstone. Handbook of AppliedCryptography. CRC. 1997.http://www.cacr.math.uwaterloo.ca/hac/Reference book (not to be read from a to z)

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3 Shoup. A Computational Introduction to Number Theory andAlgebra. Cambridge University Press. 2005.http://shoup.net/ntbTextbook on algebra for cryptographers and applications.

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Schedule and Policy (2010)

prerequitites: Cryptography and Security

lectures: 23.2 - 2.3 - 9.3 - 16.3 - 23.3 - 30.3 - 13.4 - 20.4 - 27.4 -4.5 - 11.5 - 18.5 - 25.5 - 1.6

midterm exam: 4.5 (180min open books)

survey: when announced (closed books)

information: http://lasecwww.epfl.ch/courses/ac10/

grade = max

(exam,min

(exam+1,

exam+ continuous2

))continuous = average(midterm,surveys)

surveys = average

(best

23

surveys

)

SV 2010 Advanced Crypto EPFL-SSC 15 / 20

Grade Statistics — Advanced Cryptography

2005 2006 2007 2008 2009# students at exam 3 8 9 20 8

success rate 100% 88% 89% 75% 75%average grade 4.67 4.75 5.11 4.30 4.19

6.0 3 3 35.5 2 25.0 2 1 44.5 2 2 5 14.0 1 2 4 23.5 33.0 1 1 22.52.01.5 21.0

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. . 1 Chapter 0: PreambleThis CourseAdministrative InformationOther Courses

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Spec. in Information and Communication Security

course title volume credits lecturerAdvanced Algorithms 56+42 7 MoretAlgorithms in Public-Key 28+28 4 Lenstra

CryptographyBiometrics 28+14 4 DrygajloCryptography and Security 56+28 7 VaudenayTCP/IP Networking 28+28 5 le Boudec, ThiranVLSI Design I 28+0 2 LeblebiciAdvanced Computer Architecture 28+28 4 IenneAdvanced Cryptography 28+28 4 VaudenayMedia Security 28+14 4 EbrahimiMobile Networks 28+14 4 HubauxStudent Seminar: Security Protocols 0+28 3 Oechslin, Vaudenay

and ApplicationsVLSI Design II 28+0 2 Leblebici

SV 2010 Advanced Crypto EPFL-SSC 18 / 20

Kudelski Award

Objective: to reward a student having defended a Master Thesis whichsignificatively contributes to the domain of information systemssecurity.

2005 Martin VuagnouxAUTODAFE: an Act of Software Torture

2006 Sylvain PasiniSecure Communications over Insecure Channels Using anAuthenticated Channel

2007 Alexandre KarlovBroadcast Encryption and Traitor Tracing using EllipticCurves

2009 Benoı̂t DupasquierEncrypted VoIP Speech Recognition

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Semester Project / Master Thesis

list of available proposals at LASEC:http://lasecwww.epfl.ch/teaching.shtml

bring your own ideas

SV 2010 Advanced Crypto EPFL-SSC 20 / 20

Q & A