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Blockchain Architecture, Components and Considerations
Published in Shaun Aghili, The Auditor's Guide to Blockchain Technology, 2023
Aafreen Fathima Altaf Hussain, Temitope Ipentan, Mahakpreet Singh, Grace Moyo Adeyemi
Asymmetric cryptography is also known as public-key cryptography. The revolutionary idea of cryptography was introduced by Whitfield Diffie and Martin Hellman in the 1970s. Diffie and Hellman maintained that there might be possibilities to develop a cryptosystem in which there are two different keys. A public key is used for the encryption of the plaintext, while a private key is used for the decryption of the ciphertext to plain text [73]. In this technique, the sender (Alice) encrypts the secret message with the receiver’s (Bob’s) public key and the receiver decrypts the message with his private key. The public key can be known to everyone, but the private key is only known to the receiver and needs to be protected. The keys are certified using digital signatures. Asymmetric cryptography is convenient and offers greater security, as long as the private key remains intact. The Diffie-Hellman exchange key is one of the most popular methods of key distribution [58].
Single Photon Devices
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Hamza A. Abudayyeh, Boaz Lubotzky, Ronen Rapaport
Key distribution is a way to securely transfer information between two or more parties (traditionally named Alice and Bob) by sharing cryptographic keys. In conventional key distribution methods, the key security relies on the strength of mathematical problems and the assumptions limiting the capabilities of the attacker. QKD addresses these weaknesses, by providing a provably secure cryptographic building block of single photons to share cryptographic keys. The security is based on the fact that measuring a quantum system disturbs the system, which is a fundamental characteristic of quantum mechanics. This promises that the intervention of an eavesdropper (called Eve) will leave traces that can be detected by Alice or Bob, and by using a certain protocol, one can prevent leakage of information and maintain security. However, the picture we presented is true only if the photon pulse encoding the bit contains no more than a single photon. If there is more than one photon encoding the bit, the eavesdropper can potentially detect just one photon without changing the remaining photon(s), and therefore the eavesdropping can be disguised as a loss. This attack is called photon number splitting (PNS) attack.
Key Establishment Protocols
Published in Alfred J. Menezes, Paul C. van Oorschot, Scott A. Vanstone, Handbook of Applied Cryptography, 2018
Alfred J. Menezes, Paul C. van Oorschot, Scott A. Vanstone
Diffie-Hellman key agreement provided the first practical solution to the key distribution problem, allowing two parties, never having met in advance or shared keying material, to establish a shared secret by exchanging messages over an open channel. The security rests on the intractability of the Diffie-Hellman problem and the related problem of computing discrete logarithms (§ 3.6). The basic version (Protocol 12.47) provides protection in the form of secrecy of the resulting key from passive adversaries (eavesdroppers), but not from active adversaries capable of intercepting, modifying, or injecting messages. Neither party has assurances of the source identity of the incoming message or the identity of the party which may know the resulting key, i.e., entity authentication or key authentication.
MAKA: Multi-Factor Authentication and Key Agreement Scheme for LoRa-Based Smart Grid Communication Services
Published in IETE Journal of Research, 2023
Prarthana J. Mehta, Balu L. Parne, Sankita J. Patel
The key distribution schemes are broadly categorised into two types: The first one is Public Key Infrastructure (PKI)-based key distribution scheme and the second is a symmetric key distribution scheme. In the first approach, to generate the certificates a trusted third party is involved and to authenticate each other communicating entities verify the validity of the certificates. In symmetric key-based approach, a similar secret key is shared among communicating entities and authentication is carried out by challenge-response-based authentication scheme [3]. The computation required for verification of the certificate and ever-growing size of Certificate Revocation List (CRL) are two practical issues for SG technology to incorporate PKI-based key management scheme. Moreover, if similar keys are used by all the SMs, then it will be risky to communicate securely. If an adversary succeeds to get the shared key then communication security between a service provider and the smart meter will be at risk. To solve these weaknesses it is possible to assign a unique private key to every smart meter along with the unique device identity. However, an intruder may try to get access to the secret keys of the SMs by attacking the smart meter device. Hence, it is important to protect the device identity and carry out mutual authentication between SMs and SPs. So, here a novel scheme is proposed that introduces the identity-based crypto-system to maintain the anonymity of the SM and offers secure key sharing and communication between communicating parties.