Cryptography and quantum computing

Present situation worldwide and in Switzerland

Secure cryptographic methods are essential to protect sensitive information and communication links. Common methods today are based on prime decomposition and the calculation of discrete logarithms. They include in particular the widespread Rivest-Shamir-Adleman (RSA) protocol, used for example to create digital signatures, or the Diffie- Hellman protocol, used to generate a shared key to protect a communication link. Significant progress in quantum computing presents a challenge for these methods, as quantum computers are highly efficient at mastering prime decomposition and calculating discrete logarithms.

There are fundamentally two approaches to averting the threat posed by quantum computers: post-quantum cryptography (PQC) and quantum key distribution (QKD). PQC is a collective term for cryptographic methods whose security rests on mathematical problems that quantum computers are not able to solve significantly faster than conventional computers. QKD enables the secure exchange of a key. Its security relies on physical laws governing the state of photons. In this context, the processing power and capabilities of (quantum) computers are irrelevant.

Implications for Switzerland

Despite the technological leadership of ID Quantique in the QKD market and the research leadership of various notable research groups and companies (a.o. the ETH Zurich and IBM Research – Zurich), the significance for Swiss research and for the Swiss economy is currently still rather low. However, it is likely to increase considerably over the next five years. It is therefore important to maintain and consolidate technological leadership.