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Unbounded Leakage-Resilience and Intrusion-Detection in a Quantum World

Authors:
Alper Cakan , Carnegie Mellon University
Vipul Goyal , NTT Research & Carnegie Mellon University
Chen-Da Liu-Zhang , Lucerne University of Applied Sciences and Arts & Web3 Foundatio
Joao Ribeiro , Instituto de Telecomunicações and Departamento de Matemática, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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Conference: TCC 2024
Abstract: Can an adversary hack into our computer and steal sensitive data such as cryptographic keys? This question is almost as old as the Internet and significant effort has been spent on designing mechanisms to prevent and detect hacking attacks. Once quantum computers arrive, will the situation remain the same or can we hope to live in a better world? We first consider ubiquitous side-channel attacks, which aim to leak side information on secret system components, studied in the leakage-resilient cryptography literature. Classical leakage-resilient cryptography must necessarily impose restrictions on the type of leakage one aims to protect against. As a notable example, the most well-studied leakage model is that of bounded leakage, where it is assumed that an adversary learns at most l bits of leakage on secret components, for some leakage bound l. Although this leakage bound is necessary, many real-world side-channel attacks cannot be captured by bounded leakage. In this work, we design cryptographic schemes that provide guarantees against arbitrary side-channel attacks: • Using techniques from unclonable quantum cryptography, we design several basic leakage- resilient primitives, such as public- and private-key encryption, (weak) pseudorandom func- tions, digital signatures and quantum money schemes which remain secure under (polyno- mially) unbounded classical leakage. In particular, this leakage can be much longer than the (quantum) secret being leaked upon. In our view, leakage is the result of observations of quantities such as power consumption and hence is most naturally viewed as classi- cal information. Notably, the leakage-resilience of our schemes holds even in the stronger “LOCC leakage” model where the adversary can obtain adaptive leakage for (polynomially) unbounded number of rounds. • What if the adversary simply breaks into our system to steal our secret keys, rather than mounting only a side-channel attack? What if the adversary can even tamper with the data arbitrarily, for example to cover its tracks? We initiate the study of intrusion- detection in the quantum setting, where one would like to detect if security has been compromised even in the face of an arbitrary intruder attack which can leak and tamper with classical as well as quantum data. We design cryptographic schemes supporting intrusion detection for a host of primitives such as public- and private-key encryption, digital signature, functional encryption, program obfuscation and software protection. Our schemes are based on techniques from cryptography with secure key leasing and certified deletion
BibTeX
@inproceedings{tcc-2024-34789,
  title={Unbounded Leakage-Resilience and Intrusion-Detection in a Quantum World},
  publisher={Springer-Verlag},
  author={Alper Cakan and Vipul Goyal and Chen-Da Liu-Zhang and Joao Ribeiro},
  year=2024
}