Abstract Standard post-quantum cryptography signatures can verify authenticity but inevitably compromise confidentiality by exposing message digests to the public channel—a critical vulnerability for low-entropy or high-security messages. To overcome this, we propose a Confidential Integrity Verification framework that functionally operates as a secure two-party equality test (Quantum Private Comparison). This framework verifies the integrity of shared messages without revealing their digests. Unlike classical and quantum authenticated encryption schemes, our protocol requires no pre-shared symmetric keys; it leverages post-quantum cryptography solely for authenticating the initial entanglement purification. The message equality comparison itself achieves information-theoretic confidentiality via quantum state teleportation. We demonstrate that even under realistic noisy channels, the authentication error probability can be suppressed below 10 −9 with only 194 entangled pairs. This resource efficiency, combined with intrinsic immunity to ‘harvest now, decrypt later’ attacks on the digest, provides an end-to-end, quantum-resistant solution ideal for verifying privacy-sensitive information in quantum networks, such as data post-processing in quantum key distribution.
Abstract Standard post-quantum cryptography signatures can verify authenticity but inevitably compromise confidentiality by exposing message digests to the public channel—a critical vulnerability for low-entropy or high-security messages. To overcome this, we propose a Confidential Integrity Verification framework that functionally operates as a secure two-party equality test (Quantum Private Comparison). This framework verifies the integrity of shared messages without revealing their digests. Unlike classical and quantum authenticated encryption schemes, our protocol requires no pre-shared symmetric keys; it leverages post-quantum cryptography solely for authenticating the initial entanglement purification. The message equality comparison itself achieves information-theoretic confidentiality via quantum state teleportation. We demonstrate that even under realistic noisy channels, the authentication error probability can be suppressed below 10 −9 with only 194 entangled pairs. This resource efficiency, combined with intrinsic immunity to ‘harvest now, decrypt later’ attacks on the digest, provides an end-to-end, quantum-resistant solution ideal for verifying privacy-sensitive information in quantum networks, such as data post-processing in quantum key distribution.
The phenomenal progress in quantum technologies over the past decades has laid the groundwork for the construction of quantum networks, which will channel the power of quantum theory to guarantee secure and efficient communication, computation, and much more. This thesis studies the notion of trust in quantum networks. In our information age, protecting the security or anonymity of data is a key requirement. We investigate certain protocols that are fundamental to the operation and applications of quantum networks, and propose ways to test and analyse their security, in spite of adversarial intervention. Our focus is on practical methods of verifying the untrusted components, which could be incorporated into realistic networks in the near future. To begin, we propose a protocol for authenticated communication of quantum messages, by verifying the entanglement required for quantum teleportation in an experimentally feasible way. We model the performance of our scheme in the presence of noise. Furthermore, we explore such an authenticated teleportation in the one-sided device-independent scenario, where some devices used for verification may be corrupted. We derive error-tolerant self- testing bounds and extend our results to a realistic experimental setting, demonstrating the compatibility of our protocol with state-of-the-art technology. We then study anonymity, an essential feature for communication across networks. Combining the power of classical and quantum subroutines, we build a practical protocol for anonymous communication of quantum messages, without the need to trust the players in our network, their computational power, or the entanglement they share. We end by considering the verification of graph states distributed across a network of possibly dishonest players, applying our scheme to specific graph states that are central to quantum communication and computation schemes.
Quantum cryptography is a well-stated field within quantum applications where quantum information is used to set secure communications, authentication, and secret keys. Now used in quantum devices with those purposes, particularly Quantum Key Distribution (QKD), which proposes a secret key between two parties free of effective eavesdropping, at least at a higher level than classical cryptography. The best-known quantum protocol to securely share a secret key is the BB84 one. Other protocols have been proposed as adaptations of it. Most of them are based on the quantum indeterminacy for non-orthogonal quantum states. Their security is commonly based on the large length of the key. In the current work, a BB84-like procedure for QKD based on double quantum teleportation allows the sharing of the key statement using several parties. Thus, the quantum bits of information are assembled among three parties via entanglement, instead of travelling through a unique quantum channel as in the traditional protocol. Asymmetry in the double teleportation plus post-measurement retains the secrecy in the process. Despite requiring more complex control and resources, the procedure dramatically reduces the probability of success for an eavesdropper under individual attacks, because of the ignorance of the processing times in the procedure. Quantum Bit Error Rate remains in the acceptable threshold and it becomes configurable. The article depicts the double quantum teleportation procedure, the associated control to introduce the QKD scheme, the analysis of individual attacks performed by an eavesdropper, and a brief comparison with other protocols.
Abstract Ensuring the long-term security and accessibility of digital resources is a critical challenge for libraries and archives. Traditional cryptographic methods, including RSA and elliptic curve schemes, are threatened by advances in quantum computing, which could compromise the confidentiality and authenticity of stored data. To address this, we present a Post-Quantum Digital Preservation and Secure File Sharing Framework that safeguards archival materials while enabling controlled user access. The framework integrates three core components: (i) a key encapsulation mechanism (KEM) for secure session key distribution; (ii) AES-GCM for efficient and file encryption; and (iii) digital signatures for authenticity verification. A dual-application design supports both repository operators and end-users: Repository operators encrypt, sign, and package digital assets into bundles, while users verify signatures, decrypt files, and restore content through a dedicated receiver GUI. Although the prototype employs X25519 and Ed25519 as placeholders, its architecture is fully compatible with NIST-standardized post-quantum algorithms such as Kyber (KEM) and Dilithium (signatures). By combining preservation with secure file sharing, the framework ensures confidentiality, authenticity, integrity, and resistance to quantum-era threats, offering a practical and forward-looking solution for Digital repositories.
Using the highly entangled six-qubit genuine state we present a quantum private comparison(QPC)protocol, which enables two users to compare the equality of two bits of their secrets in every round comparison with the assistance of a semi-honest third party(TP). The proposed protocol needs neither unitary operations nor quantum entanglement swapping technology, both of which may consume expensive quantum devices. Single particle measurements and Bell-basis measurements, which are easy to implement with current technologies, are employed by two users and TP in the proposed protocol, respectively. The proposed protocol can withstand all kinds of outside attacks and participant attacks. Moreover, none of information about the two users’ private secrets and the comparison result is leaked out to TP.
Abstract Using the highly entangled six-qubit genuine state we present a quantum private comparison (QPC) protocol, which enables two users to compare the equality of two bits of their secrets in every round comparison with the assistance of a semi-honest third party (TP). The proposed protocol needs neither unitary operations nor quantum entanglement swapping technology, both of which may consume expensive quantum devices. Single particle measurements and Bell-basis measurements, which are easy to implement with current technologies, are employed by two users and TP in the proposed protocol, respectively. The proposed protocol can withstand all kinds of outside attacks and participant attacks. Moreover, none of information about the two users' private secrets and the comparison result is leaked out to TP.
The emergence of quantum computing poses a significant security threat to the current classical cryptography system since it has the potential to outperform the current classical computer in some specific tasks due to its unique principle of operation. This necessitates finding a method that is resistant to quantum computers to securely transfer information. This research addresses these challenges by proposing a novel method combining quantum key distribution (QKD), specifically the E91 protocol, with the classical encryption-authentication protocol ChaCha20-Poly1305, and concealing information within another message through steganography to securely transfer audio messages. A shared secret key is created between the communicating parties using E91 QKD, which exploits the stellar protection of quantum entanglement against eavesdropping. The shared key is hashed through the SHA–3 hash function to generate a fixed-length, high-entropy symmetric key. The audio message is hidden inside another audio signal through steganography. The steganographic signal is encrypted using ChaCha20-Poly1305 AEAD in order to provide another layer of obfuscation as well as a means to verify integrity. Through rigorous experiments, we validated the robustness of the proposed methodology in both classical and quantum attacks. The processing of secret audio signals of varying duration (00:01:32 to 00:01:36) exhibits consistent encryption results. The encrypted stego audios show high randomness, with an average entropy of 15.9984, an average correlation of 1 . 4627 × 1 0 − 5 , an average UACI of 49.9977%, and an average NSCR of 99.9985%. We demonstrated the safety of the shared key using the CHSH inequality test, where in the presence of an eavesdropper, the CHSH value is much less than 2 2 . In addition, the integrity of the secret audio is also validated through the verification of the authenticator tag generated during the encryption process. Our research offers a novel framework for secure audio transmission, combining classical encryption and authentication methods with QKD to enhance confidentiality, integrity, and resilience against eavesdropping and tampering, ensuring robust end-to-end security.