Research on new cryptographic mechanisms to protect against the threat of quantum computers has attracted great interest, especially due to the impact that this new technologies will have on the security of cyber-operations. After the widely tested and implemented Quantum Key Distribution (QKD) protocol for the generation of symmetric encryption keys, other protocols are being explored, such as Quantum Digital Signatures (QDS). Their classic analogues based on asymmetric cryptography will be vulnerable to Shor's quantum algorithm. Given the applicability that QDS could have in multi-domain operations, in this work we have analyzed and implemented a quantum-safe QDS protocol in a simulated environment provided with real QKD-generated keys. First, we recreated a basic three-user scenario composed of one signer and two verifiers, and later generalized by increasing the number of users by simulating a scheme with one signer and multiple verifiers. Our simulation also allows one participating user to be malicious, thus playing with the number of attack vectors and the breaking points of the forwarding chain. In addition, a use case is presented in which the QDS protocol is performed to confirm orders along the command chain, demonstrating its applicability. This paper was originally presented at the NATO Science and Technology Organization Symposium (ICMCIS) organized by the Information Systems Technology (IST) Panel, IST-200RSY — the ICMCIS, held in Skopje, North Macedonia, 16–17 May 2023.
Research on new cryptographic mechanisms to protect against the threat of quantum computers has attracted great interest, especially due to the impact that this new technologies will have on the security of cyber-operations. After the widely tested and implemented Quantum Key Distribution (QKD) protocol for the generation of symmetric encryption keys, other protocols are being explored, such as Quantum Digital Signatures (QDS). Their classic analogues based on asymmetric cryptography will be vulnerable to Shor's quantum algorithm. Given the applicability that QDS could have in multi-domain operations, in this work we have analyzed and implemented a quantum-safe QDS protocol in a simulated environment provided with real QKD-generated keys. First, we recreated a basic three-user scenario composed of one signer and two verifiers, and later generalized by increasing the number of users by simulating a scheme with one signer and multiple verifiers. Our simulation also allows one participating user to be malicious, thus playing with the number of attack vectors and the breaking points of the forwarding chain. In addition, a use case is presented in which the QDS protocol is performed to confirm orders along the command chain, demonstrating its applicability. This paper was originally presented at the NATO Science and Technology Organization Symposium (ICMCIS) organized by the Information Systems Technology (IST) Panel, IST-200RSY — the ICMCIS, held in Skopje, North Macedonia, 16–17 May 2023.
With the quantum computational paradigm rapidly developing across the world, new vulnerabilities on currently deployed cryptography protocols are to be taken in consideration. A possible answer to said vulnerabilities is using quantum technologies on cryptography. For a quantum-assisted cryptography protocol, key pairs can be generated via quantum state measurements. This protocol is known as quantum key distribution, of extended use for providing security against any algorithm-based attack to the keys. Ensured the key protection against eavesdroppers, a QKD-assisted protocol can focus its security analysis on party behaviour. Depending on the protocol rules and steps to follow, users can attempt attacks on it with the purpose of causing disagreement or misunderstanding between parties. In this work, we present a simulation environment for a hybrid, quantum-assisted digital signature (QDS) protocol. The configurations available for the simulated network as well as the digital signature protocol make it possible to design specific communication scenarios, such as attacks on the message integrity, forging and repudiation attempts or noisy communication across the quantum channels.
Asymmetric cryptography plays a critical role in the security, authenticity and sustainability of widely used electronic documents on a level comparable to the security and authenticity of a traditional paper documents in transport and logistics. However, security of the majority of the asymmetric cryptographic techniques currently in use, including those used to confirm the validity of electronic documents, will be compromised due to the forthcoming development of quantum computers. The concept of a quantum computer is no longer just a theory. The race for supremacy in quantum technology is on among countries since it is the most drastic technology in the world. On a large enough quantum computer, an attacker can easily generate fake digital signatures by applying Shor’s algorithm. Digital communications and electronic transactions could be devoid of the guarantee of authenticity and non-repudiation if this vulnerability is not addressed. Post-quantum cryptography strives to provide useful techniques that are resistant to attacks utilizing quantum computers in order to address the threat to existing asymmetric cryptography. In this research, we examine the current post-quantum digital signature algorithms used to confirm the validity of an electronic document in addition to comprehending the utilization of digital signing. Overall, we conclude that in order to define the next generation of electronic documents and to address the quantum threat, it is crucial to standardize a quantum-resistant digital signature scheme.
The quantum digital signature (QDS) has attracted much attention as it ensures the nonrepudiation, unforgeability, and transferability of signature messages based on information-theoretic security. Amiri et al. ( Phys. Rev. A 93 032325 ) proposed the first practical QDS protocol based on orthogonal coding, which has realized information-theoretic security and become the mainstream paradigm in QDS research. The procedure of QDS involves two essential stages, the one is the distribution stage, in which Alice-Bob and Alice-Charlie individually utilize the three-intensity decoy-state quantum key distribution protocol but without error correction or privacy amplification, namely, key-generation protocol, to generate correlated bit strings, the other is the messaging stage, in which Alice transmits signature messages to the two recipients. However, previous theoretical and experimental studies both overlooked the modulation errors that may be introduced in the state preparation process due to the imperfections in modulator devices. Under the traditional framework of GLLP analysis method, these errors will significantly reduce the actual signature rates. Therefore, we propose a state-preparation-error tolerant QDS and use parameter analysis to characterize the state preparation error to make the simulation analysis more realistic. In addition, we analyze the signature rates of the present scheme by using the three-intensity decoy-state method. Compared with previous QDS protocols, our protocol almost shows no performance degradation under practical state preparation errors and exhibits a maximum transmission distance around 180 km. Furthermore, state preparation errors do not have a significant influence on the bit error rate induced by normal communication between the legitimate users or the one produced by an eavesdropper. These results prove that the method proposed in this paper has excellent robustness against state preparation errors and it can achieve much higher signature rates and signature distances than other standard methods. Besides, signature rates are basically unchanged under different total pulse numbers, which shows that our protocol also has good robustness against the finite-size effect. Additionally, in the key generation process, our method is only required to prepare three quantum states, which will reduce the difficulty of experiment realizations. Furthermore, the proposed method can also be combined with the measurement-device-independent QDS protocol and the twin-field QDS protocol to further increase the security level of QDS protocol. Therefore, our work will provide an important reference value for realizing the practical application of QDS in the future.
The exponential development in Quantum Computing is becoming a threat to the existing asymmetric cryptographic algorithms like RSA (Rivest, Shamir, Adleman). A threat to these public key cryptographic algorithms is a threat to the entire Internet itself, as algorithms like RSA are the basic building blocks of existing secure Internet communication. Thus, a new area of quantum cryptography emerged, that lead to the development of Post-Quantum Cryptography (PQC) algorithms and Quantum-safe Internet protocol Quantum Key Distribution (QKD). These systems, which are generally known as Quantum Cryptographic Systems, have many practical limitations that make them complex and expensive to be implemented or even experimented with, in a real-life scenario. Therefore, to develop new protocols and analyze the feasibility of the existing protocols in a cost-effective manner, we need efficient simulation frameworks. So, in this paper, we are profiling some of the recent Quantum Cryptographic based networks and Quantum Key Distribution (QKD) simulation frameworks and conducting a systematic and thorough analysis of the implementation and functionalities of these experimental platforms, with an aim to build a universal quantum testbed in the future.
Guaranteeing nonrepudiation, unforgeability as well as transferability of a signature is one of the most vital safeguards in today's e-commerce era. Based on fundamental laws of quantum physics, quantum digital signature (QDS) aims to provide information-theoretic security for this cryptographic task. However, up to date, the previously proposed QDS protocols are impractical due to various challenging problems and most importantly, the requirement of authenticated (secure) quantum channels between participants. Here, we present the first quantum digital signature protocol that removes the assumption of authenticated quantum channels while remaining secure against the collective attacks. Besides, our QDS protocol can be practically implemented over more than 100 km under current mature technology as used in quantum key distribution.
As the digital front becomes our new frontier, and digital data becomes increasingly vulnerable to highly sophisticated cyber attacks, conventional encryption approaches may no longer be sufficient to withstand a quantum attack. The focus of this work is to deploy a simulation of the BB84 protocol, one of the first Quantum Key Distribution (QKD) protocols developed by Charles Bennett and Gilles Brassard in 1984. The simulation involves two communicating parties, Alice and Bob, with Bob creating a secret keys generated cryptographically and sending it reliably over to Alice using quantum bits, or qubits. By leveraging quantum mechanics, this protocol ensures that any interception can be identified, thus bolstering both the integrity and confidentiality of the key exchange through scientists' understanding of superposition and the no-cloning principle. In the simulation, the potential of quantum communication to achieve secure key distribution over an insecure channel is demonstrated. Differently from traditional encryption protocols, QKD guarantees security not on computational but on physical basis. The aim of this paper is to show the feasibility and robustness of the BB84 protocol for actual cryptographic applications. This models the protocol between Alice and Bob, which paves the way for quantum-proof encryption systems and is a relevant step towards next generation cyber security.