arXiv subjects

Yeong Cherng Liang

Publications and source records attributed to Yeong Cherng Liang.

3 recordsLinked to original sources

arXiv2004

Quantum Cryptography: Security Criteria Reexamined

We find that the generally accepted security criteria are flawed for a whole class of protocols for quantum cryptography. This is so because a standard assumption of the security analysis, namely that the so-called square-root measurement is optimal for eavesdropping purposes, is not true in general. There are rather large parameter regimes in which the optimal measurement extracts substantially more information than the square-root measurement.

quant-ph↗

arXiv2003

How well can you know the edge of a quantum pyramid?

The methods of quantum cryptography enable one to have perfectly secure communication lines, whereby the laws of quantum physics protect the privacy of the data exchanged. Each quantum-cryptography scheme has its own security criteria that need to be met in a practical implementation. We find, however, that the generally accepted criteria are flawed for a whole class of such schemes.

quant-ph↗

arXiv2003

Tomographic Quantum Cryptography

We present a protocol for quantum cryptography in which the data obtained for mismatched bases are used in full for the purpose of quantum state tomography. Eavesdropping on the quantum channel is seriously impeded by requiring that the outcome of the tomography is consistent with unbiased noise in the channel. We study the incoherent eavesdropping attacks that are still permissible and establish under which conditions a secure cryptographic key can be generated. The whole analysis is carried out for channels that transmit quantum systems of any finite dimension.

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