About InfiniQuant

Max Planck Institute for the Science of Light

InfiniQuant is a team, hosted within the Quantum Information Processing group of Christoph Marquardt at the Max Planck Institute for the Science of Light in Erlangen, Germany. The group is part of Gerd Leuchs’ division and focuses on fundamental research, whereas InfiniQuant investigates possible applications for quantum communication scenarios.  InfiniQuant’s team is currently lead by scientists Imran Khan and Christoph Marquardt.

Quantum Communication

Quantum communication is the transfer of information using the resources of quantum mechanics. While many different protocols exist, the most prominent one is quantum key distribution (QKD), which provides a way to exchange secret keys in an information-theoretically provable secure way.

Quantum Cryptography


Immune against Quantum Computers

Security provided by the laws of physics

Future-proof and long-term security
Will a quantum computer break the security of QKD? No - the security proofs that are behind QKD assume that an eavesdropper has the full power of quantum mechanics. This includes the eavesdropper having access to a quantum computer and all its future possible operations. As such QKD systems remain secure, even with the advent of a quantum computer.
What makes Quantum Key Distribution so secure? As the name suggests, keys are distributed, not messages. As such, QKD protocols make sure that the key exchange was not eavesdropped at the time of the exchange. This is done by exchanging quantum states that, when eavesdropped, leave a signature of the eavesdropper which is detectable by the legitimate communication partners. The laws of quantum mechanics (which are deeply rooted in physics and related to fundamental concepts like causality) render this form of key exchange using quantum resources provably secure.
Is QKD secure against future attacks? Yes - classical cryptography can be eavesdropped during transmission, recorded and decrypted later, once more sophisticated means are available. This cannot be done for QKD, since attacks on the key distribution have to be performed during the actual distribution in order to be able to decrypt any messages later on. As long as the laws of physics don’t change, QKD remains secure, even against future attacks of more powerful classical computers or novel quantum computers.

Compatible with existing infrastructure

Steadily decreasing implementation cost

Requires dedicated hardware
Is QKD compatible with existing telecom infrastructure? Yes - the technology investigated at InfiniQuant is based on coherent telecommunication technology that has a long history and is developed to the highest industry standards. We adapt this technology to suit the requirements of QKD, while maintaining compatibility to the existing telecom infrastructure.
Why is QKD then not deployed everywhere already? QKD requires dedicated hardware, which is still of considerable cost but decreasing each year by continued research and development. As such, QKD is currently recommended for high-security applications. Although future developments in quantum computation might require a widescale deployment of QKD to ensure a secure network architecture.
Why use hardware based crypto when there is software? For software-based cryptography no security guarantee can be given as the required proofs remain elusive until today. In contrast, QKD provides the highest level of security and is especially suited for long term security.

Works in conjunction with classical crypto
Will QKD replace classical cryptography? No. In fact, classical cryptography is needed for QKD protocols. During the post-processing stage an authenticated classical channel is required, which can for example be implemented via the Wegman-Carter authentication scheme. Once a key is distributed, the one-time pad can be used for encryption and decryption. Both classical schemes can be proven information-theoretically secure. In contrast, most other classical cryptographic primitives rely on assumptions about computational complexity. This means that they work only if the attacker does not have sufficient computing power to crack a mathematically hard (but not uncrackable) problem. QKD instead is based on the laws of quantum mechanics and its security can be proven in an information-theoretic manner.