In distributed systems, entities perform the predefined tasks distributively and have to communicate quite frequently. Confidentiality is the primary security requirement in such systems. There should be some secure mechanism whereby a pair of entities can securely communicate with each other. In most of the applications of distributed systems, computational and communication resources are limited and any such mechanism that ensures security of data under transmission should consider these computational and communicational constraints. Symmetric key cryptography emerges as one of the effective mechanisms to secure the data in distributed systems. The security of a symmetric key mechanism purely depends on the secrecy of the session key. In this paper, we have proposed a protocol for the sharing of session key between communicating entities securely. The proposed protocol secures the session through asymmetric key mechanism and once the session key is securely shared, the entities can communicate through the shared session key.
In distributed systems, entities perform the predefined tasks distributively and have to communicate quite frequently. Confidentiality is the primary security requirement in such systems. There should be some secure mechanism whereby a pair of entities can securely communicate with each other. In most of the applications of distributed systems, computational and communication resources are limited and any such mechanism that ensures security of data under transmission should consider these computational and communicational constraints. Symmetric key cryptography emerges as one of the effective mechanisms to secure the data in distributed systems. The security of a symmetric key mechanism purely depends on the secrecy of the session key. In this paper, we have proposed a protocol for the sharing of session key between communicating entities securely. The proposed protocol secures the session through asymmetric key mechanism and once the session key is securely shared, the entities can communicate through the shared session key.
Asymmetric group key agreement allows a group of users to negotiate a public encryption key that corresponds to several decryption keys, and each decryption key can only be computed by one group member. This novel notion ensures the confidentiality of communication among group members and allows any external entity to send messages to the group. However, the existing authenticated asymmetric group key agreement protocols are designed in identity-based cryptosystem or certificateless public key cryptosystem, which are not widely deployed. In this paper, we propose an efficient authenticated asymmetric group key agreement protocol. The protocol captures the security of secrecy, known-key security, key-compromise impersonation, unknown key-share and key control while being resistant to active attacks. The security of our protocol is reduced to the k-BDHE problem.
According to modern cybersecurity, the concept of public key cryptography or asymmetric cryptography is one of the basics. Public key cryptography uses two keys: A private key is kept in secret and a public key is distributed publicly. Traditionally, symmetric cryptography uses a single key for everything from encryption to decoding, while quantum methods operate differently. Digital signatures, key exchange data channels, and even secure communication have been made possible thanks to the paradigm shift in cryptography. This chapter highlights the emergence of the rudimentary concepts, computational rules, and relevant advantages of using public key cryptography. It is paramount that this technology is deployed to ensure the integrity, confidentiality, and authenticity of digital communications.
The security of traditional cryptographic schemes is based on mathematical puzzles that cannot be cracked by current computers. However, the rapid development of quantum computers has the potential to greatly reduce the time and resources required to crack these encryption schemes. Although true quantum supremacy may still be years away, it is imperative to adopt anti-quantum algorithms proactively. This preemptive approach aims to thwart "catch first, decrypt later" attacks, wherein attackers intercept and store encrypted data with the intent of decrypting it once quantum computing becomes sufficiently advanced. This threat is particularly critical for protocols like Secure Shell (SSH), which is widely used for secure communication over unsecured networks. In this paper, we propose an innovative approach to enhance the security of public-key distribution within the SSH protocol. Our method integrates quantum-resistant algorithms to ensure that even with the advent of quantum computing, the confidentiality and integrity of SSH sessions are maintained. We emphasize the importance of using cryptographic protocols that operate over open channels, which, while not necessarily confidential, must be authenticated to prevent tampering. In such scenarios, attackers may be able to intercept and even extract information, but they should not be able to alter the data.
Private key cryptography suffers from a major weakness - it requires sharing of a secret key between two parties. An intruder can copy the secret key as it is being exchanged, thereby severely compromising the security of the system. Thus a private key cryptographic system depends entirely on secrecy of the key. Public key cryptography does not have a key distribution problem but its security relies on the fact that determining the factors of a number that is the product of two very large prime numbers is not computationally feasible. It has been shown that a quantum computer can solve the prime factors of very large numbers in polynomial time which would otherwise take millions of years. Public key cryptography will therefore become insecure if quantum computing becomes a reality. Quantum cryptography, originally presented in BB84 protocol, avoids all these issues by encrypting the shared key using a series of photons. In this paper a key distribution protocol based on the concepts of BB84 is proposed It provides an additional layer of security by sending the key data bits twice; during the second transmission the original key bits or their complements are randomly chosen for transmission. The sender informs the receiver about the orientation of the key bits during the second round of transmission only after the data has been sent out.
In conventional security mechanism, security services based on symmetric key cryptography assume keys to be distributed prior to secure communications. The core function of exchanging and sharing a secret key between two endpoints are the secure key management methodology which is one of the most critical elements need to be more concerned when integrating cryptographic functions into the system. In case the key management mechanisms is weak can lead to the vulnerability holes or a potentially fatal outsider attacks as the harmful effects to the system. Since, there is still no standardized architecture or protocol that can provide cross application symmetric key management services. Therefore, this paper approaches a secure key management model and its custom protocols to build Thailand quantum trusted network with offers simultaneous quantum key distribution to multiple user overtime. Consequently, the proposed technique has also overcome the limitation of quantum point-to-point key sharing. Based on the discussion of key management security requirement, deal with generic key management concepts and designing the new custom protocols to close the possibility loopholes, to offers reliability and convenience of use, as well as to introduce a secure and efficient key management technique for quantum cryptography network in Thailand where any communication services can take place.
Privacy-preserving data-sharing mechanisms traditionally rely on data anonymization techniques, which aim to dissociate individual records from their corresponding data subjects in order to transform sensitive information into a form that minimizes the risk of re-identification. In parallel, trust-broker models have emerged as an additional layer of protection, whereby authorized data providers disclose controlled contact information that enables potential data users to request access under predefined conditions determined by the data owner. In contemporary data-sharing environments, cryptography remains a fundamental pillar for ensuring confidentiality and integrity during data exchange. Cryptographic protection typically involves two operations: an encryption process, in which the sender transforms plaintext into ciphertext that is unintelligible to unauthorized entities, and a decryption process, in which only the intended recipient restores the ciphertext to its original form. Both operations rely on a cryptographic algorithm paired with one or more secret keys. Symmetric-key cryptography employs a single shared key for both encryption and decryption. In contrast, asymmetric cryptography uses a mathematically linked pair of keys, where one key is used for encryption and the other for decryption. When the encryption key is publicly available while the corresponding decryption key remains private, only the legitimate recipient holding the private key is capable of recovering the plaintext. This cryptographic structure forms the basis for securing data confidentiality against unauthorized access in both classical and quantum-aware communication systems.