Security Protocols

Motivation and basic notions (1 hour)
Attacker models and examples for attacks. Conventional communication security objectives  (confidentiality, authenticity, integrity, non-repudiation, anonymity, prevention of traffic analysis). Placement of security services in the network protocol stack.

Overview of cryptographic primitives (2 hours)
Main properties of encryption algorithms, hash functions, asymmetric key schemes,  and practical considerations related to cryptographic parameters.
 
Basic protocols (4 hours)
Introduction, analysis, and practical applications of the main block encryption modes. Introduction, analysis, and practical applications of some known MAC function constructions. Asymmetric key encryption and digital signature in practice, related PKCS standards, elliptic curve cryptography.  

Random number generation (1 hour)
True and pseudo random number generators, and measuring their quality. Attack models and known attacks against random number generators. Design requirements for pseudo random number generators, illustrative examples.
 
Cryptographic (program) libraries (1 hour)
Introduction of some known cryptographic libraries (e.g., OpenSSL) and illustration of their usage in practice through examples.

Analysis and design of key exchange protocols (2 hours)
Goals, types, and main services of key exchange protocols. Typical mechanisms, design patterns and considerations. Manual analysis of some known protocols, introduction of typical attack methods. Formal modeling and analysis of key exchange protocols with the Proverif analysis tool.

Public Key Infrastructure (PKI) (2 hours)
Definition of the terms certificate, certificate chain, and Certification Authority. Introducing the elements, functions, and processes in a PKI through the life-cycle of a certificate and in relation to the X.509 standard.  Key management issues and certificate revocation mechanisms. Legal background of PKI and electronic signatures.
 
Secure communication protocols (8 hours)
•    Operation and analysis of some known security protocols (SSL/TLS, IPsec, 802.1AE (MACsec), 802.1X, 802.11):
•    SSL/TLS (3 hours): SSL/TLS subprotocols, detailed description of the TLS handshake and TLS record protocols, known weaknesses and attacks, lessons learned and identification of protocol design principles  
•    IPsec (1 hour): operation of the AH, ESP, and IKEv2 protocols, examples for IPsec applications
•    802.1X and 802.11 security (3 hours): operation and analysis of the WEP, WPA1, WPA2 protocols, attacks against WEP and WPA1, lessons learned and identification of protocol design principles
•    802.1AE (1 hour): operation and application examples

Practical authentication protocols (2 hours)
Known authentication and authorization protocols (Kerberos, SAML and OAuth), operation and analysis.

Security protocols in resource constrained environments (2 hours)
Bluetooth security. Key exchange and secure communications in wireless sensor networks. Security and privacy in RFID systems.

Security protocols for cloud based services (2 hours)
Secure data storage in the cloud, computing with encrypted data.

Protocols for anonymous communication (1 hour)
Defining and quantifying anonymity. Mix networks. Operation of the Tor network, as a practical implementation of the Mix concept.

Classroom exercises extend the lectures by illustration of the usage of concrete security tools, and help deepening knowledge by solving challenges in the following domains:  
1. block encryption modes: exercises related to the properties of the different block encryption modes
2. MAC constructions: exercises related to the properties of MAC functions
3. random number generation: exercises related to the properties of random number generators
4. usage of crypto libraries: illsutration of the usage of some known crypto libraries (e.g., OpenSSL) through examples
5. analysis and design of key exchange protocols: challenges related to attacking and fixing key exchange protocols
6. security protocols for cloud based services: illustration of design principles and practical implementation issues using Tresorit as an example
7. analysis of anonymous communication systems: exercises to calculate the level of anonymity in some anonymous communication systems