Measurement-device-independent quantum digital signatures

Abstract

Digital signatures play an important role in software distribution, modern communication, and financial transactions, where it is important to detect forgery and tampering. Signatures are a cryptographic technique for validating the authenticity and integrity of messages, software, or digital documents. The security of currently used classical schemes relies on computational assumptions. Quantum digital signatures (QDS), on the other hand, provide information-theoretic security based on the laws of quantum physics. Recent work on QDS Amiri et al., Phys. Rev. A 93, 032325 (2016); Yin, Fu, and Zeng-Bing, Phys. Rev. A 93, 032316 (2016) shows that such schemes do not require trusted quantum channels and are unconditionally secure against general coherent attacks. However, in practical QDS, just as in quantum key distribution (QKD), the detectors can be subjected to side-channel attacks, which can make the actual implementations insecure. Motivated by the idea of measurementdevice-independent quantum key distribution (MDI-QKD), we present a measurement-device-independent QDS (MDI-QDS) scheme, which is secure against all detector side-channel attacks. Based on the rapid development of practical MDI-QKD, our MDI-QDS protocol could also be experimentally implemented, since it requires a similar experimental setup.

Experimental Demonstration of High-Rate Measurement-Device-Independent Quantum Key Distribution over Asymmetric Channels

“…In MDI quantum digital signature (QDS) [39,40,46], there exists a sufficiently large signature length which makes the protocol secure, if the condition…”

Multi-bit quantum digital signature based on temporal quantum ghost imaging

“…It is worth giving a comparison between the proposed mutli-bit QDS protocol and previous protocols when they are applied to sign long massages. Previous QDS protocols [15][16][17][18][19][20][21][22][23] focused on the single-bit signature. For a long message in practical applications, it should be signed bit by bit since these QDS protocols are based on the raw keys generated by QKD for each bit.…”

“…If both of the noise factors in the two ghost images, defined as the inverse of signal-to-noise ratio, are lower than the acceptance threshold T h B accept , Bob will accept the message and forwards it to Charlie through the classical channel. The noise factor here is similar to the concept of mismatch in previous QDS [15][16][17][18][19][20][21][22][23] where Bob checks Alice's raw keys to decide whether he accepts the message or not.…”

“…In real applications, the increasing noise factor is attributed to the perturbation by the eavesdropping in the distribution stage and the malicious forging in the messaging stage. Actually, the noise factor can be treated as the mismatch of signature elements in the traditional QDS [15][16][17][18][19][20][21][22][23]. On the other hand, Bob has an acceptance threshold T h B accept .…”

“…Such breakthroughs motivated several notable advances in experimental demonstrations of QDS [14], where the transmission distance has been remarkably extended by utilizing phase-encoded states [15][16][17] and polarization-encoded states [18][19][20] in recent years. Additionally, several pro- * zwei@tsinghua.edu.cn posals have been implemented for improving the security of QDS, such as measurement-device-independent (MDI) QDS [21,22], which is immune to detector side-channel attacks, and passive decoy-state QDS for circumventing the leakage of the signal and decoy information to attackers [23]. However, those QDS protocols were dealing with the case of one-bit signature and the iterations of the procedure would be considerable for longer messages, limiting the feasibility in practical applications.…”