Fail-stop protocol
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Round 1 generate the state
on n qubits and send the kth qubit to the kth player keeping one part
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Generate the state
on n qubits, an equal superposition of the numbers between 1 and 
.Distribute the n qubits between all the players
- Receive the quantum messages from all players and wait for the next communication round, thus forcing the adversary to choose which messages were passed.
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Round 2: Measure (in the standard base) all
qubits received in round I. Select the player with the highest leader value
(ties broken arbitrarily) as the "leader" of the round. Measure the
leader’s coin in the standard base.
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Set the output of the QuantumCoinFlip protocol:
= measurement outcome of the leader’s coin.
