This lecture explores both the practical and theoretical aspects of symmetric cryptography, structured into three parts.
(1) Provable Security: We begin by examining provable security, a foundational concept of modern cryptography. Within this part, we will study practical constructions such as the Feistel cipher and explore various block cipher modes of operation.
(2) Cryptanalysis: The second part shifts the focus to the cryptanalysis of widely used cryptographic primitives that are deemed secure in practice despite missing formal proofs of security. A key example is the AES encryption scheme. We will explore the cryptanalytic efforts that confirm the confidence in AES.
(3) Implementation Security: The final part of the lecture focuses on the critical risks of implementing cryptographic primitives without expert guidance. For example, we will demonstrate how a simple timing attack can completely compromise the security of AES if effective countermeasures are not employed. To conclude, we will explore fundamental strategies to mitigate such vulnerabilities and strengthen the resilience of cryptographic implementations.
- Dozent*in: Maximilian Orlt