Views
5 years ago

# x - Faculty of Computer Science - Technische Universität Dresden

x - Faculty of Computer Science - Technische Universität Dresden

## 155 Preparation:

155 Preparation: Definition for information-theoretical security How would you define information-theoretical security for encryption? Write down at least 2 definitions and argue for them!

Definition for information-theoretical security 1. Definition for information-theoretical security (all keys are chosen with the same probability) �S � S � const � IN �x � X: |{k � K| k(x) = S}| = const. (1) The a-posteriori probability of the plaintext x is W(x|S), after the attacker got to know the ciphertext S. 2. Definition �S � S �x � X: W(x|S) = W(x). (2) Both definitions are equivalent (if W(x) > 0): According to Bayes: W ( x) �W ( S | x) W ( x | S) � W ( S) Therefore, (2) is equivalent to �S � S �x � X: W(S|x) = W(S). (3) We show that this is equivalent to �S � S � const' � IR �x � X: W(S|x) = const'. (4) 156

faculty of computer science - Fakultät Informatik - Technische ...
Slides - Technische Universität Dresden
Optimierung und Frustration: - Technische Universität Dresden
Statistics beyond Physics - Technische Universität Dresden
OCL By Example Lecture - Technische Universität Dresden
Graphs - Www-st.inf.tu-dresden.de - Technische Universität Dresden
4. Context Awareness - Faculty of Computer Science - Technische ...
3. Mobile Internet - Faculty of Computer Science - Technische ...
7. Location-based Se.. - Faculty of Computer Science - Technische ...
Talk - Technische UniversitÃ¤t Dresden
3. Adaptation - Faculty of Computer Science - Technische ...
5. Adaptation - Faculty of Computer Science - Technische ...
2. Mobile Internet - Faculty of Computer Science - Technische ...
02 - Technische UniversitÃ¤t Dresden
Wiki Event Navigation - Computer Networks - Technische Universität ...
Content Sharing - Technische UniversitÃ¤t Dresden
SAP AG - Faculty of Computer Science
First Presentation - Faculty of Computer Science
6. Context Awareness - Faculty of Computer Science - Technische ...
Computer Science and Engineering - Technische Universiteit ...
5. Location-based Se.. - Faculty of Computer Science - Technische ...
Folie 1 - Faculty of Computer Science
Folie 1 - Faculty of Computer Science
Folie 1 - Faculty of Computer Science
X - Technische Universität Dresden
X - Technische Universität Dresden
Technische Universität Dresden - Computer Networks - Technische ...
diplomarbeit - Computer Networks - Technische Universität Dresden
M - Technische Universität Dresden
PDF file - Technische Universität Dresden