Security in Computer Networks Multi

Areas of Teaching and Research •

5/48 Examples of changes w.r.t. ano

The massmedia „newspaper“ will

Multimedia Forensics

Multimedia Forensics

Areas of Teaching and Research •

15 General Aims of Education in IT-

General Aims of Education in IT-sec

General Aims of Education in IT-sec

…but no this way! First stupid an

Aims of Education: Offers by other

3 Cryptographic basics Table of Con

History of Communication Networks (

Important Terms computers interconn

threats: Threats and corresponding

confidentiality integrity availabil

commands universal universal Trojan

Which protection measures against w

money time Considered maximal stren

Strength of the attacker (model) At

Electromagentic radiation >dir AUTT

Why should I protect myself... ? ..

Previously on Security and Cryptogr

Multilateral security (2nd version)

Prevent the unintended Achieve the

Protection Goals: Definitions Confi

Correlations between protection goa

Physical security assumptions Each

Shell-shaped arrangement of the fiv

Golden rule Correspondence between

66 Lookahed: Why autentication: Adm

PIN protects access to chip New Ger

Identification of IT-systems by IT-

Password based authentication • S

One-way functions - cryptographic h

MD5 Hash in the Wild • United Sta

mission statement:= “USCYBERCOM p

Password based authentication • E

Remaining problems of password base

• main idea: Cryptanalytic Time -

• 2 nd example - breaking of PINs

Remaining problems of password base

Remaining problems of password base

Password based authentication • S

Password based authentication • S

Password based authentication • s

Password based authentication • s

Password based authentication • p

Password based authentication • (

• OTP Implementations - hash chai

Biometrics: Physiological / Behavio

• Enrolment phase: • Verificati

• Pros: Biometrics: Pros and Cons

• Pros: Biometrics: Pros and Cons

• Pros: Biometrics: Pros and Cons

ROC Curve and Security Problems of

Enhanced Security: Multi-biometric

Computer virus vs. transitive Troja

Further problems 1. Specify exactly

Aspects of distribution Distributed

Availability Infrastructure with th

more detailed notation Symmetric en

Key exchange using symmetric encryp

more detailed notation Domain of tr

more detailed notation Symmetric au

Key distribution using digital sign

Whom are keys assigned to? Comments

severity a) passive a1) ciphertext-

Basic facts about “cryptographica

Grundlagen - Sicherheit kryptograph

security information theoretic acti

Hybrid cryptosystems (2) Even more

Information-theoretically secure en

ciphertext S 00 01 10 11 equally di

154 Keys have to be very long for i

Definition for information-theoreti

Another definition for information-

Symmetric authentication systems (2

About cryptographically strong syst

clear: in NP � but difficulty can

Search of prime numbers (1) 1. Are

Z n : ring of residue classes mod n

Calculating with and without p,q (3

Compose ? Calculating with and with

Calculating with and without p,q (7

Calculating with and without p,q (9

Calculating with and without p,q (1

Calculating with and without p,q (1

Calculating with and without p,q (1

184 The s 2 -mod-n-Pseudo-random Bi

s 2 -mod-n-generator as symmetric e

s 2 -mod-n-generator as asymmetric

Security of the s 2 -mod-n-generato

Security of PBGs more precisely (1)

Security of PBGs more precisely (3)

constructive proof often Scheme of

Alg.2: has to demand uniformity Why