Eavesdropping in Semiquantum Key Distribution Protocol
This addresses security vulnerabilities in quantum key distribution for cryptographic applications, but it is incremental as it builds on existing protocols.
The paper tackles the problem of eavesdropping in a semiquantum key distribution protocol by proposing a two-way strategy that listens to the channel in both directions, resulting in Eve extracting more information than with a one-way approach under the same disturbance level.
In semiquantum key-distribution (Boyer et al.) Alice has the same capability as in BB84 protocol, but Bob can measure and prepare qubits only in $\{|0\rangle, |1\rangle\}$ basis and reflect any other qubit. We study an eavesdropping strategy on this scheme that listens to the channel in both the directions. With the same level of disturbance induced in the channel, Eve can extract more information using our two-way strategy than what can be obtained by the direct application of one-way eavesdropping in BB84.