Recently, Zhao et al. proposed a semi-quantum bi-signature (SQBS) scheme based on W states with two quantum signers and just one classical verifier. In this study, we highlight three security issues with Zhao et al.'s SQBS scheme. In Zhao et al.'s SQBS protocol, an insider attacker can perform an impersonation attack in the verification phase and an impersonation attack in the signature phase to capture the private key. In addition, an eavesdropper can perform a man-in-the-middle attack to obtain all of the signer's secret information. All of the above three attacks can pass the eavesdropping check. Without considering these security issues, the SQBS protocol could fail to ensure the signer's secret information.
Recently, Zhao et al. proposed a semi-quantum bi-signature (SQBS) scheme based on W states with two quantum signers and just one classical verifier. In this study, we highlight three security issues with Zhao et al.'s SQBS scheme. In Zhao et al.'s SQBS protocol, an insider attacker can perform an impersonation attack in the verification phase and an impersonation attack in the signature phase to capture the private key. In addition, an eavesdropper can perform a man-in-the-middle attack to obtain all of the signer's secret information. All of the above three attacks can pass the eavesdropping check. Without considering these security issues, the SQBS protocol could fail to ensure the signer's secret information.
Currently, quantum signature protocols assume that all participants in the protocol (signers, verifiers, and arbitrators) should exhibit quantum capabilities. If quantum devices are lacking, the quantum signature protocol cannot be implemented. However, quantum devices are not widely used, and not all users can own quantum devices. Boyer et al. first proposed the concept of the semi-quantum environment. Zhao et al. proposed a semi-quantum signature protocol with double signers based on the W state. Yang et al. discovered that in the semi-quantum signature protocol with double signers developed by Zhao et al., an internal attacker could launch an impersonation attack during the verification and signature stages to capture the private key and use it to impersonate the user’s identity. In addition, the eavesdropper can obtain all the secret information of the signers by performing a man-in-the-middle attack. All three attack modes can pass the eavesdropping check. Hence, if these security problems are not solved, the signature of the semi-quantum signature protocol with double signers proposed by Zhao et al. cannot be completed safely. Therefore, based on Bell states, a new semi-quantum signature protocol of double signers was developed in this study. The proposed protocol not only resists impersonation attacks and man-in-the-middle attacks but also resists other common attack modes.
Due to the rapid advancement of quantum computers, there has been a furious race for quantum technologies in academia and industry. Quantum cryptography is an important tool for achieving security services during quantum communication. Designated verifier signature, a variant of quantum cryptography, is very useful in applications like the Internet of Things (IoT) and auctions. An identity-based quantum-designated verifier signature (QDVS) scheme is suggested in this work. Our protocol features security attributes like eavesdropping, non-repudiation, designated verification, and hiding sources attacks. Additionally, it is protected from attacks on forgery, inter-resending, and impersonation. The proposed scheme benefits from the traditional designated verifier signature schemes. In the proposed scheme, the signer encrypts a message with his or her private key, and the designated verifier validates the accompanying QDVS using the signer’s public key, which is the signer’s name or email address, which makes the quantum signature system’s key management simpler. It uses an entangled state while signing and verifying the signature; however, the verifier is not required to compare quantum states. A detailed comparison analysis with other similar schemes provides more security for the proposed scheme. Furthermore, the proposed scheme’s effectiveness and feasibility are validated using quantum simulations.
In recent years, identity-based quantum signature protocols have received much attention due to their unique advantages. Based on Bell states, we propose an efficient identity-based quantum signature scheme. In our scheme, the signer’s private key is generated from their identity information. The signer uses the private key and secret parameters to generate a signature for the verifier. The verifier, who possesses the identity information of the signer, can authenticate the signature. Our proposed scheme ensures signature non-forgeability and non-repudiation. In addition, the protocol does not require the preparation of long-term quantum memory or the performance of quantum swap tests, making it more efficient than previous schemes.
A recent paper proposed a semi-quantum secret sharing (SQSS) scheme based on Bell states [A. Yin et al., Mod. Phys. Lett. B. https://doi.org/10.1142/S0217984917501500 ]. This protocol was presumed that only the sender has the quantum power and all participants perform classical operations. However, we find this protocol is not that secure as it is expected. We can utilize the intercept-resend method to attack this scheme. Then, we give an improvement strategy based on semi-quantum key distribution, which ensures that the new scheme resists the attack we have proposed.
Semi-quantum signature (SQS) schemes aim to enable quantum signature functionality in scenarios where only a subset of participants possess full quantum capabilities, thereby improving practical deployability while preserving quantum security advantages. Within this framework, we present a practical SQS protocol based on Bell states. The protocol is designed so that only the signer requires full quantum capability, significantly alleviating the quantum burden on the remaining participants. To strengthen security in semi-quantum environments, we incorporate an improved eavesdropping-detection mechanism that more effectively detects tampering. Compared with many existing schemes, which do not explicitly consider tampering of already generated signatures in their unforgeability analyses, the proposed protocol is designed to remain secure in the presence of such tampering.
Abstract Designated verifier signature (DVS) schemes can be applied in many scenes, such as E-voting and E-bidding use DVS attributes to protect the secret of participants. Most traditional DVS schemes are vulnerable to quantum computer attacks. Then, an identity-based semi-trusted third-party quantum DVS (STQDVS) scheme is proposed, which is safe for quantum means of attack. In new STQDVS scheme, the third participant prepares entangled Bell states and allocates them to the signer and the designated verifier (DV). The signer uses the identity information as her public key and the measurement results of corresponding quantum sequences as her private key to generate the signature. The DV applies the identity information as his public key and the measurement results of corresponding quantum sequences as her private key to verify the signature. Non-transferability and hidden origin are guaranteed by the fact that the DV can generate the same signature as the signatory by means of a simulated signature step. Security analysis has shown that attacks such as forgery, inter-resending, and impersonation are ineffective for the proposed scheme and that even third-party cannot forge signatures. On the other hand, the whole process of the scheme does not require any quantum key distribution protocols, quantum one-way functions, and quantum state exchange tests, which makes the STQDVS scheme relatively simple and more efficient than similar schemes.