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-

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

GMR - signature system (2) Construc

To factor is difficult (1) Theorem:

Solution of problem 1 (1) Tree of r

Note In the proof you dispose the

Key generation 1) Choose two prime

Proof (2) Holds, of course, for m

secret area plaintext x random numb

secret area text with signature and

( x s ) Attack on digital signature

Active Attack of Davida against RSA

secret area plaintext x random numb

Faster calculation of the secret op

64-bit block plaintext L 0 IP round

L i-1 L i = R i-1 Decryption Why do

Generation of a key for each of the

L i-1 One round complement compleme

Generalization of DES 1.) 56 � 16

e.g. 64 bits with DES ECB Main prob

Cipher Block Chaining (CBC) All lin

� plaintext block n memory for ci

Block length a Length of the output

shift register 1 b CFB for authenti

Plain Cipher Block Chaining (PCBC)

Utilization of indeterministic bloc

Diffie-Hellman key agreement (1) pr

andom number 1 Domain of trust secr

Find a generator in cyclic group Z

x, s(x), “pass” or “fail” r

Signature system for blindly provid

Reconstruction of the secret: Thres

adio television videophone phone in

adio television videophone phone in

Since about 1990 reality Video-8 ta

Problems with exchanges Unsolved pr

Questions: Attacker (-model) • Ho

Questions: Attacker (-model) • Ho