Cryptographic Protocols under Quantum Attacks

TL;DR

This thesis investigates the security of cryptographic protocols in the quantum setting, addressing unique challenges and opportunities posed by quantum effects to ensure protocol robustness against quantum adversaries.

Contribution

It provides a comprehensive analysis of classical and quantum cryptographic security proofs, highlighting new techniques to adapt classical proofs to quantum environments.

Findings

Classical proof techniques often fail in quantum settings.

Quantum properties can be exploited to strengthen cryptographic security.

The work identifies conditions under which protocols remain secure against quantum attacks.

Abstract

The realm of this thesis is cryptographic protocol theory in the quantum world. We study the security of quantum and classical protocols against adversaries that are assumed to exploit quantum effects to their advantage. Security in the quantum world means that quantum computation does not jeopardize the assumption, underlying the protocol construction. But moreover, we encounter additional setbacks in the security proofs, which are mostly due to the fact that some well-known classical proof techniques are forbidden by certain properties of a quantum environment. Interestingly, we can exploit some of the very same properties to the benefit of quantum cryptography. Thus, this work lies right at the heart of the conflict between highly potential effects but likewise rather demanding conditions in the quantum world.