Non-Destructive Zero-Knowledge Proofs on Quantum States, and Multi-Party Generation of Authorized Hidden GHZ States
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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.
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