184 research outputs found
Distributed Relay Protocol for Probabilistic Information-Theoretic Security in a Randomly-Compromised Network
We introduce a simple, practical approach with probabilistic
information-theoretic security to mitigate one of quantum key distribution's
major limitations: the short maximum transmission distance (~200 km) possible
with present day technology. Our scheme uses classical secret sharing
techniques to allow secure transmission over long distances through a network
containing randomly-distributed compromised nodes. The protocol provides
arbitrarily high confidence in the security of the protocol, with modest
scaling of resource costs with improvement of the security parameter. Although
some types of failure are undetectable, users can take preemptive measures to
make the probability of such failures arbitrarily small.Comment: 12 pages, 2 figures; added proof of verification sub-protocol, minor
correction
Quantum protocols for anonymous voting and surveying
We describe quantum protocols for voting and surveying. A key feature of our
schemes is the use of entangled states to ensure that the votes are anonymous
and to allow the votes to be tallied. The entanglement is distributed over
separated sites; the physical inaccessibility of any one site is sufficient to
guarantee the anonymity of the votes. The security of these protocols with
respect to various kinds of attack is discussed. We also discuss classical
schemes and show that our quantum voting protocol represents a N-fold reduction
in computational complexity, where N is the number of voters.Comment: 8 pages. V2 includes the modifications made for the published versio
Multiparty Delegated Quantum Computing
Quantum computing has seen tremendous progress in the past years. However,
due to limitations in scalability of quantum technologies, it seems that we are
far from constructing universal quantum computers for everyday users. A more
feasible solution is the delegation of computation to powerful quantum servers
on the network. This solution was proposed in previous studies of Blind Quantum
Computation, with guarantees for both the secrecy of the input and of the
computation being performed. In this work, we further develop this idea of
computing over encrypted data, to propose a multiparty delegated quantum
computing protocol in the measurement-based quantum computing framework.Comment: 22 page
Non-Destructive Zero-Knowledge Proofs on Quantum States, and Multi-Party Generation of Authorized Hidden GHZ States
Due to the special no-cloning principle, quantum states appear to be very
useful in cryptography. But this very same property also has drawbacks: when
receiving a quantum state, it is nearly impossible for the receiver to
efficiently check non-trivial properties on that state without destroying it.
In this work, we initiate the study of Non-Destructive Zero-Knowledge Proofs
on Quantum States. Our method binds a quantum state to a classical encryption
of that quantum state. That way, the receiver can obtain guarantees on the
quantum state by asking to the sender to prove properties directly on the
classical encryption. This method is therefore non-destructive, and it is
possible to verify a very large class of properties. For instance, we can force
the sender to send different categories of states depending on whether they
know a classical password or not. Moreover, we can also provide guarantees to
the sender: for example, we can ensure that the receiver will never learn
whether the sender knows the password or not.
We also extend this method to the multi-party setting. We show how it can
prove useful to distribute a GHZ state between different parties, in such a way
that only parties knowing a secret can be part of this GHZ. Moreover, the
identity of the parties that are part of the GHZ remains hidden to any
malicious party. A direct application would be to allow a server to create a
secret sharing of a qubit between unknown parties, authorized for example by a
third party Certification Authority.
Finally, we provide simpler "blind" versions of the protocols that could
prove useful in Anonymous Transmission or Quantum Onion Routing, and we
explicit a cryptographic function required in our protocols based on the
Learning With Errors hardness problem.Comment: 50 page
Classically Verifiable NIZK for QMA with Preprocessing
We propose three constructions of classically verifiable non-interactive zero-knowledge proofs and arguments (CV-NIZK) for QMA in various preprocessing models.
1. We construct a CV-NIZK for QMA in the quantum secret parameter model where a trusted setup sends a quantum proving key to the prover and a classical verification key to the verifier. It is information theoretically sound and zero-knowledge.
2. Assuming the quantum hardness of the learning with errors problem, we construct a CV-NIZK for QMA in a model where a trusted party generates a CRS and the verifier sends an instance-independent quantum message to the prover as preprocessing. This model is the same as one considered in the recent work by Coladangelo, Vidick, and Zhang (CRYPTO \u2720). Our construction has the so-called dual-mode property, which means that there are two computationally indistinguishable modes of generating CRS, and we have information theoretical soundness in one mode and information theoretical zero-knowledge property in the other. This answers an open problem left by Coladangelo et al, which is to achieve either of soundness or zero-knowledge information theoretically. To the best of our knowledge, ours is the first dual-mode NIZK for QMA in any kind of model.
3. We construct a CV-NIZK for QMA with quantum preprocessing in the quantum random oracle model. This quantum preprocessing is the one where the verifier sends a random Pauli-basis states to the prover. Our construction uses the Fiat-Shamir transformation. The quantum preprocessing can be replaced with the setup that distributes Bell pairs among the prover and the verifier, and therefore we solve the open problem by Broadbent and Grilo (FOCS \u2720) about the possibility of NIZK for QMA in the shared Bell pair model via the Fiat-Shamir transformation
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