Improving the Security of Quantum Protocols via Commit-and-Open

Understand

We consider two-party quantum protocols starting with a transmission of some random BB84 qubits followed by classical messages.

• We show a general "compiler" improving the security of such protocols: if the original protocol is secure against an "almost honest" adversary, then the compiled protocol is secure against an arbitrary computationally bounded (quantum) adversary.
• The compilation preserves the number of qubits sent and the number of rounds up to a constant factor.
• The compiler also preserves security in the bounded-quantum-storage model (BQSM), so if the original protocol was BQSM-secure, the compiled protocol can only be broken by an adversary who has large quantum memory and large computing power.