Cryptography

Cryptographic methods are the backbone of the digital society: They protect personal data, secure communication infrastructures, and ensure the integrity of critical processes. At Fraunhofer SIT, we cover the entire spectrum of cryptographic research—from basic research and novel encryption paradigms to practical security analysis of deployed protocols and systems. Examples of application areas for our work in this field include IT security in healthcare, bioinformatics, and local government.

Future-Proof Cryptography

With the advent of powerful quantum computers, many of the cryptographic methods used today are on the verge of becoming obsolete. We develop and analyze post-quantum cryptography based on mathematically intractable problems—in particular, lattice-based cryptography, which can withstand quantum attacks.

In addition, our researchers are also working on QKD (Quantum Key Distribution) in particularly security-critical areas to secure the exchange of cryptographic keys using quantum physics. The actual data, however, is protected using conventional encryption methods.

Another area of focus is homomorphic encryption: it enables computations to be performed directly on encrypted data without ever processing it in plaintext. For the healthcare sector, this technology brings about important fundamental changes: clinical analyses, AI-supported diagnostics, and epidemiological evaluations can thus be performed without patient data ever having to leave its secure encrypted state—neither at the processing site nor in the cloud environment. Our research investigates how these methods can be applied efficiently and practically, for example in medical image processing or bioinformatics.

Crypto-Agility

To keep cryptographic methods up-to-date and secure, they must be regularly adapted and updated. To implement this as easily and quickly as possible, the need to replace cryptographic methods should be taken into account right from the outset when setting up systems. This approach is called crypto-agility. Our researchers provide practical guidance on how organizations can become crypto-agile or securely migrate their data sets.

Security Analyses of Cryptographic Protocols

Mathematically sound cryptography offers no absolute protection if protocols are incorrectly specified or implemented. We systematically analyze the security of cryptographic protocols in real-world use: from encrypted email communication and TLS to specialized communication standards in the healthcare sector.

In addition to office IT, medical facilities have another, often overlooked vulnerability: the medical technology communication protocols themselves. Widely used standards such as DICOM and HL7, as well as their implementations, contain security vulnerabilities that we systematically investigate in production environments using custom-developed vulnerability scanning tools. In practice, data transmitted via these protocols is still mostly unencrypted today. That is why we apply insights from the analysis of general cryptographic protocols to develop recommendations for improving standards and implementations.