Our research in cryptopgraphy focuses on the security analysis of symmetric cryptographic primitives. For this purpose, we apply and adapt existing mathematical frameworks to practical designs and design methods. We conduct basic and applied research and offer consulting services.
Current Research Topics
- Authenticated Encryption
Authenticated encryption is an important part in information security. Whenever two parties communicate over a network an authenticated encryption algorithm might be used to provide both privacy and authentication of the data. In most applications, there is not much value in keeping the data secret if they are not authenticated. Authentication of data is often of more value than their confidentiality.
While ciphers and hash functions receive a great deal of attention from the cryptographic community due to such high-profile competitions as NIST's AES and SHA-3 selections as well as ECRYPT's eSTREAM project, authenticate encryption schemes and message authentication codes have been arguably less popular among researchers. However, with the CAESAR project on track there is a growing need for fundamental and applied research to support the choice of a portfolio of new authenticated encryption algorithms that will be secure for the next decades.
- Cryptographic Hash Functions
Cryptographic hash functions play a fundamental role in modern information security. Already in 1976 Diffie and Hellman identified the need for a one-way hash function as a building block for a digital signature scheme. Today cryptographic hash functions are deployed in a large number of applications, protocols and cryptographic schemes. They are used for instance for digital signature, password protection, random number generation, key derivation, integrity protection, malicious code detection, message authentication, and many more.
In the last years, much progress has been made in the cryptanalysis of hash functions. Weaknesses have been shown for most of the commonly used hash functions like MD5 and SHA-1. As a consequence NIST has decided to organize a public competition in order to design a new hash function, leading to the selection of Keccak as SHA-3 in October 2012. However, with the cryptographic community joining forces in the SHA-3 competition, the SHA-2 family got considerably less attention in the last few years. Since NIST explicitly recommends both, SHA-2 and SHA-3, the cryptanalysis of SHA-2 and SHA-3 is of great interest to get a good view on their security margin.