Arbitrated Quantum Signature Scheme Research Articles

A Verifiable Arbitrated Quantum Signature Scheme Based on Controlled Quantum Teleportation

In this paper, we present a verifiable arbitrated quantum signature scheme based on controlled quantum teleportation. The five-qubit entangled state functions as a quantum channel. The proposed scheme uses mutually unbiased bases particles as decoy particles and performs unitary operations on these decoy particles, applying the functional values of symmetric bivariate polynomial. As such, eavesdropping detection and identity authentication can both be executed. The security analysis shows that our scheme can neither be disavowed by the signatory nor denied by the verifier, and it cannot be forged by any malicious attacker.

Offline Arbitrated Semi-Quantum Signature Scheme with Four-Particle Cluster State

The emergence of the semi-quantum concept makes it possible for people without quantum capabilities to communicate securely. An offline arbitrated semi-quantum signature scheme based on four-particle cluster states is put forward, in which two classical parties could complete the signature with the assistance of the quantum arbitrator. Different from the typical arbitrated quantum signature schemes, the arbitrator in our protocol acts as a relay station for delivering signature and no longer intervenes in the direct authentication of signature, leaving the signature receiver with full authentication rights. There is no additional direct communication between the signer and the receiver, which reduces the complexity of transmission. Besides, security analysis manifests that the proposed semi-quantum signature scheme is secure.

Arbitrated quantum signature scheme with quantum teleportation by using two three-qubit GHZ states

Arbitrated quantum signature (AQS) scheme based on quantum teleportation has better flexibility and practicability. In this paper, we propose an arbitrated quantum signature scheme with quantum teleportation by using two three-qubit GHZ states. It has been proved that a cluster state has a maximal persistence when compared with an entangled state, and it is also more robust against decoherence. To resist against Alice’s disavowals or Bob’s (outside attacker’s) repudiation, two secret quantum key strings are pre-shared and two random numbers are introduced. The security analysis results show that our AQS scheme can make sure about the impossibility of disavowals by the signer Alice and repudiations by the verifier Bob, and the impossibility of forgeries by any illegal attacker. In addition, the proposed scheme does not require the complex quantum measurement operation, only Bell state measurements, projective measurements and unitary operation are needed to recover the arbitrary two-qubit state, which is the message copy from the signer Alice to the verifier Bob, and that is an appealing advantage in the implementation of a practical quantum communication network.

Efficient arbitrated quantum signature scheme without entangled states

In the most arbitrated quantum signatures (AQSs), the signers and verifiers need to perform the quantum key distribution protocols or some other protocols to share secret keys before signing a signature. In some schemes, the entangle states, which are not easily implemented, have to be prepared and distributed among the partners. Based on single photon and one-way functions, a new AQS scheme without entangled states is proposed. In our scheme, the signer generates a quantum signature on the classical message with his/her private key and the one-way function. The arbitrator communicates with the signer through a classical unencrypted channel. The signer and verifier need not perform the key distribution protocol before signing a message. On the other hand, without entangled states, our scheme can reduce the complexity of implementation. Then, our scheme is more efficient than the similar schemes. At the same time, our scheme is secure against forgery attack and disavowal attack.

Security analysis and improvement of an arbitrated quantum signature scheme

We analyze the security of Jiang et al.’s arbitrated quantum signature scheme based on local indistinguishability of orthogonal product states. First, Jiang et al.’s scheme cannot resist against the forgery attack. Second, it is insecure against disavowal attack. Then, an improved arbitrated quantum signature scheme is proposed. The new scheme overcomes the security drawbacks of Jiang et al.’s scheme and it is secure against forgery attack and disavowal attack. What is more, it is more efficient than the old scheme. On the other hand, our quantum signature scheme is based on product states, which can be obtained straightforwardly, thus our scheme is easier to implement than the schemes using cluster states.

Arbitrated quantum signature scheme with quantum walk-based teleportation

Quantum walks can be applied for some quantum information processing tasks such as quantum search, element distinctness, state transfer and teleportation. In this paper, we present an arbitrated quantum signature scheme with quantum walk-based teleportation. The teleportation is used for the transmission of message copy from the signer Alice to the verifier Bob. The necessary entangled states for teleportation do not need to be prepared in advance in the initial phase and can be produced naturally via quantum walk in the signature phase. Furthermore, to resist against Bob’s existential forgery for Alice’s signature under known message attack in the previous arbitrated quantum signature proposals, we employ a random number and a public board in the verification phase. Security analyses show the suggested scheme is with impossibility of disavowal of Alice and Bob, impossibility of forgery of anyone. Discussions indicate that the scheme may not prevent the disavowal of Alice and we advance the potential improvements on it. Note that the proposed arbitrated quantum signature scheme may be feasible because quantum walks prove to be implemented in different physical systems and experiments.

Controlled SWAP attack and improved quantum encryption of arbitrated quantum signature schemes

The quantum one-time pad (QOTP) usually serves as the quantum encryption to encrypt quantum messages in arbitrated quantum signature (AQS) schemes. The original QOTP is a qubit-by-qubit encryption algorithm with message and encrypted signature always appearing in pair in AQS, which will lead to the vulnerability of the AQS scheme. By comparing the two quantum state pairs in AQS with the C-SWAP attack, it is possible for the attacker to obtain the signer’s key, which leads to the security weakness of AQS. Accordingly, we propose a new attack on AQS scheme for the first time. In order to deal with the attack on AQS scheme, QOTP must be replaced by an improved quantum encryption scheme. Based on QOTP with confusion, we proposed an improved quantum encryption scheme which can resist the attack in AQS scheme. Security analysis shows that the improved quantum encryption scheme works efficiently and securely.

Arbitrated quantum signature scheme based on quantum walks

<sec>Quantum signature is quantum counterpart of classical digital signature, which has been widely applied to modern communication, such as electronic payment, electronic voting and electronic medical, owing to its great implication in ensuring the authenticity and the integrity of the message and the non-repudiation. Arbitrated quantum signature (AQS) is an important and practical type of quantum signature. The AQS algorithm is a symmetric key cryptography-based quantum signature algorithm, and its implementation requires the trusted arbitrator to be directly involved. In this paper, employing the key-controlled chained CNOT (KCCC) operation as the appropriate encryption (decryption) algorithm, we suggest an AQS scheme based on teleportation of quantum walks with two coins on a four-vertex cycle, which is used to transfer the message copy from the sender to the receiver. In light of the model of teleportation of quantum walks, the sender encodes the message to be signed into her or his coin state, and the necessary entangled states can be created as a result of the conditional shift between the coin state and the position state. The measurements performed on the generated entangled states are the bases of signature production and message recovery. Then according to the classical measurement results from the sender, the receiver performs the appropriate local unitary operations (i.e., Pauli operations) on his own coin state to recover the original message and further verifies the validity of the completed signature by using the appropriate verification algorithms under the aid of the trustworthy arbitrator. </sec><sec>The suggested AQS scheme makes the following contributions: 1) the necessary entangled states for quantum teleportation of message copy do not need preparing in advance, and they can be produced automatically by the first step of quantum walks; 2) the scheme satisfies the features of non-repudiation, un-forgeability and non-disavowal due to the use of the KCCC operation; 3) the scheme may be achieved by linear optical elements such as beam splitters, wave plates, etc., because quantum walks have proven to be realizable in different physical systems and experiments.</sec><sec>Analysis and discussion show that the proposed AQS scheme possesses the impossibility of disavowals by the signer and the receiver and impossibility of forgeries by anyone. Comparisons reveal that the designed AQS protocol is favorable. Furthermore, it provides an idea by employing the quantum computing model into quantum communication protocols with a possible improvement with respect to its favorable properties, for example, the automatic generation of entangled states via the first step of quantum walks on different models. In the near future, we will further investigate the production of entanglement by quantum walks and its applications with some improvements in designing the quantum communication protocols.</sec>

Arbitrated quantum signature scheme with continuous-variable squeezed vacuum states**Project supported by the National Natural Science Foundation of China (Grant Nos. 61379153 and 61572529).

We propose an arbitrated quantum signature (AQS) scheme with continuous variable (CV) squeezed vacuum states, which requires three parties, i.e., the signer Alice, the verifier Bob and the arbitrator Charlie trusted by Alice and Bob, and three phases consisting of the initial phase, the signature phase and the verification phase. We evaluate and compare the original state and the teleported state by using the fidelity and the beam splitter (BS) strategy. The security is ensured by the CV-based quantum key distribution (CV-QKD) and quantum teleportation of squeezed states. Security analyses show that the generated signature can be neither disavowed by the signer and the receiver nor counterfeited by anyone with the shared keys. Furthermore, the scheme can also detect other manners of potential attack although they may be successful. Also, the integrality and authenticity of the transmitted messages can be guaranteed. Compared to the signature scheme of CV-based coherent states, our scheme has better encoding efficiency and performance. It is a potential high-speed quantum signature scheme with high repetition rate and detection efficiency which can be achieved by using the standard off-the-shelf components when compared to the discrete-variable (DV) quantum signature scheme.

Forgeable quantum messages in arbitrated quantum signature schemes

Recently, the concept on `forgeable quantum messages' in arbitrated quantum signature schemes was introduced by T. Kim et al. [Phys. Scr., 90, 025101 (2015)], and it has been shown that there always exists such a forgeable quantum message for every known arbitrated quantum signature scheme with four quantum encryption operators and the specific two rotation operators. We first extend the result to the case of any two unitary rotation operators, and then consider the forgeable quantum messages in the schemes with four quantum encryption operators and three or more rotation operators. We here present a necessary and sufficient condition for existence of a forgeable quantum message, and moreover, by employing the condition, show that there exists an arbitrated quantum signature scheme which contains no forgeable quantum message-signature pairs.

An Arbitrated Quantum Signature Scheme without Entanglement**Supported by the National Natural Science Foundation of China under Grant No. 61303039, Sichuan Youth Science and Technique Foundation No. 2017JQ0048, Fundamental Research Funds for the Central Universities (Nos.2682014CX095), CSC Scholarship, and EU ICT COST CryptoAction No. IC1306

Several quantum signature schemes are recently proposed to realize secure signatures of quantum or classical messages. Arbitrated quantum signature as one nontrivial scheme has attracted great interests because of its usefulness and efficiency. Unfortunately, previous schemes cannot against Trojan horse attack and DoS attack and lack of the unforgeability and the non-repudiation. In this paper, we propose an improved arbitrated quantum signature to address these secure issues with the honesty arbitrator. Our scheme takes use of qubit states not entanglements. More importantly, the qubit scheme can achieve the unforgeability and the non-repudiation. Our scheme is also secure for other known quantum attacks.

Network-based Arbitrated Quantum Signature Scheme with Graph State

Implementing an arbitrated quantum signature(QAS) through complex networks is an interesting cryptography technology in the literature. In this paper, we propose an arbitrated quantum signature for the multi-user-involved networks, whose topological structures are established by the encoded graph state. The determinative transmission of the shared keys, is enabled by the appropriate stabilizers performed on the graph state. The implementation of this scheme depends on the deterministic distribution of the multi-user-shared graph state on which the encoded message can be processed in signing and verifying phases. There are four parties involved, the signatory Alice, the verifier Bob, the arbitrator Trent and Dealer who assists the legal participants in the signature generation and verification. The security is guaranteed by the entanglement of the encoded graph state which is cooperatively prepared by legal participants in complex quantum networks.

High-Efficient Arbitrated Quantum Signature Scheme Based on Cluster States

The arbitrated quantum signature characteristics including the security and the efficiency are investigated and a new efficient and secure arbitrated quantum signature is proposed. It is shown that the proposed scheme exhibits an efficiency of 64 %. Furthermore, to gain a higher security, the decoy photons security checking is employed.

Security Analysis of an Arbitrated Quantum Signature Scheme with Bell States

Recently, to resist attacks using the anticommutativity of nontrivial Pauli operators, an arbitrated quantum signature scheme with Bell states (Int. J. Theor. Phys. 53(5), 1569–1579 2014) was proposed. The scheme randomly adds Hadamard operations to strengthen the quantum one-time pad encryption. Based on this, it claimed that the scheme could resist the receiver’s existential forgery and no party had chances to change the message without being discovered. This paper introduces two security issues of the scheme: It can’t resist the signer’s disavowal and the receiver’s existential forgery. Furthermore, we show that the scheme is still vulnerable to the receiver’s existential forgery even if the Hadamard operation in the encryption algorithm is replaced with any 2nd-order unitary operation.

Arbitrated quantum signature scheme based on cluster states

Cluster states can be exploited for some tasks such as topological one-way computation, quantum error correction, teleportation and dense coding. In this paper, we investigate and propose an arbitrated quantum signature scheme with cluster states. The cluster states are used for quantum key distribution and quantum signature. The proposed scheme can achieve an efficiency of 100 %. Finally, we also discuss its security against various attacks.

Arbitrated Quantum Signature Scheme with Continuous-Variable Coherent States

Motivated by the revealing features of the continuous-variable (CV) quantum cryptography, we suggest an arbitrated quantum signature (AQS) protocol with CV coherent states. It involves three participants, i.e., the signer Alice, the verifier Bob and the arbitrator Charlie who is trustworthy by Alice and Bob. Three phases initializing phase, signing phase and verifying phase are included in our protocol. The security of the signature scheme is guaranteed by the generation of the shared keys via the CV-based quantum key distribution (CV-QKD) and the implementation process of the CV-based quantum teleportation as well. Security analysis demonstrates that the signature can be neither forged by anyone nor disavowed by the receiver and signer. Moreover, the authenticity and integrality of the transmitted messages can be ensured. The paper shows that a potential high-speed quantum signature scheme with high detection efficiency and repetition rate can be realized when compared to the discrete-variable (DV) quantum signature scheme attributing to the well characteristics of CV-QKD.

A Novel Quantum Blind Signature Scheme with Four-particle GHZ States

In an arbitrated quantum signature scheme, the signer signs the message and the receiver verifies the signature’s validity with the assistance of the arbitrator. We present an arbitrated quantum blind signature scheme by using four-particle entangled Greenberger-Horne-Zeilinger (GHZ) states. By using the special relationship of four-particle GHZ states, we cannot only support the security of quantum signature, but also guarantee the anonymity of the message owner. It has a wide application to E-payment system, E-government, E-business, and etc.

Quantum signature scheme for known quantum messages

When we want to sign a quantum message that we create, we can use arbitrated quantum signature schemes which are possible to sign for not only known quantum messages but also unknown quantum messages. However, since the arbitrated quantum signature schemes need the help of a trusted arbitrator in each verification of the signature, it is known that the schemes are not convenient in practical use. If we consider only known quantum messages such as the above situation, there can exist a quantum signature scheme with more efficient structure. In this paper, we present a new quantum signature scheme for known quantum messages without the help of an arbitrator. Differing from arbitrated quantum signature schemes based on the quantum one-time pad with the symmetric key, since our scheme is based on quantum public-key cryptosystems, the validity of the signature can be verified by a receiver without the help of an arbitrator. Moreover, we show that our scheme provides the functions of quantum message integrity, user authentication and non-repudiation of the origin as in digital signature schemes.

Quantum messages with signatures forgeable in arbitrated quantum signature schemes

Even though a method to perfectly sign quantum messages has not been known, the arbitrated quantum signature scheme has been considered as one of the good candidates. However, its forgery problem has been an obstacle to the scheme becoming a successful method. In this paper, we consider one situation, which is slightly different from the forgery problem, that we use to check whether at least one quantum message with signature can be forged in a given scheme, although all the messages cannot be forged. If there are only a finite number of forgeable quantum messages in the scheme, then the scheme can be secured against the forgery attack by not sending forgeable quantum messages, and so our situation does not directly imply that we check whether the scheme is secure against the attack. However, if users run a given scheme without any consideration of forgeable quantum messages, then a sender might transmit such forgeable messages to a receiver and in such a case an attacker can forge the messages if the attacker knows them. Thus it is important and necessary to look into forgeable quantum messages. We show here that there always exists such a forgeable quantum message-signature pair for every known scheme with quantum encryption and rotation, and numerically show that there are no forgeable quantum message-signature pairs that exist in an arbitrated quantum signature scheme.

Arbitrated quantum signature scheme based on reusable key

An arbitrated quantum signature scheme without using entangled states is proposed. In the scheme, by employing a classical hash function and random numbers, the secret keys of signer and receiver can be reused. It is shown that the proposed scheme is secure against several well-known attacks. Specifically, it can stand against the receiver’s disavowal attack. Moreover, compared with previous relevant arbitrated quantum signature schemes, the scheme proposed has the advantage of less transmission complexity.