Cryptography entails the science and the method of securing confidential information/data against the adversary by utilizing decryption and encryption techniques according to appropriate procedures and rules. Cryptography aims at protecting data from unauthorized users. Cryptography falls under two categories: symmetric key cryptography, or secret key cryptography, and asymmetric key cryptography, or public key cryptography (Panhwar et al., 2019). In symmetric key encryption, the same key gets utilized among decryption and encryption techniques. The advantage of such an algorithm entails low computing power and remains fast during the encryption procedure (Panhwar et al., 2019). The symmetric key encryption algorithm separates into two modes: stream and block cipher. In block cipher, all the data get divided into blocks and chunks, and data is based on block size, and the key is offered for data encryption (Sowmiya & Prabavathi, 2019). In contrast, in stream cipher, the data is separated into bits, including 0101010101, and gets randomized after the application of the encryption rule (Panhwar et al., 2019).
On the other hand, in the asymmetric key encryption method, various keys get used for decryption and encryption processes. The first key remains public and gets distributed publicly, while the second key remains private, and the users keep them confidential (Panhwar et al., 2019). According to Santoso et al. (2020), Knowing the used private key remains challenging. The benefits of asymmetric key encryption include enhanced security because keys are utilized differently for decryption and encryption procedures. The utilized keys are more extended than symmetric key encryption algorithms. However, it leads to lower operating speed. (Kekunnaya et al., 2019).
Symmetric key distribution and Asymmetric key distribution
Asymmetric key distribution includes an algorithm that ensures the generated key does not become symmetric and the authoritative power remains in the unique server. It ensures that no certificate is legitimately signed without the unique server signature. Moreover, it entails a particular scheme for distributing and generating unequal shares through a Trusted Dealer to every registered peer available in the system. It ensures that no transaction gets completed without the combination of one compulsory share from the special server (Sonalker, 2002).
Symmetric key distribution includes delivering a key to two users needing to exchange data without permitting others to view the key because symmetry encryption requires two users to share a similar key which others must not access to exchange data/information. The sender distributes keys by choosing the key and delivering it to the receiver. A trusted party can choose the key and deliver it physically to the receiver and the sender. If the receiver and the sender have utilized the key, one user can transmit the new key to another, encrypted utilizing the old key. In addition, if the receiver and the sender each possess an encrypted link to the third party, the third party can deliver the key to the encrypted connection to the receiver and the sender (Yashaswini, 2015)
BB84 quantum key distribution protocol security analysis and discussion
The QKD, or the quantum key distribution, starts a secret key-sharing routine between two distant users (Alice and Bob) in the presence of Eve, the eavesdropper. The BB84-QKD remains a central point of quantum information technology. Different QKD protocols have emerged since the ancient BB84 protocol, including high dimensional quantum key distribution, which possesses a high capacity for encoding various bits on one photon and robust tolerance to channel noise (Wang et al., 2022). According to Mafu et al. (2022), the BB84 quantum key distribution protocols belong to the P&M or prepare and measure protocols. The protocol tends to leverage the no-cloning theorem, making the states of duplicating quantum impossible.
As a result, it prevents the eavesdropper from copying the quantum states, wiretapping the quantum communication channels, developing a key, and delivering the original states to the receiver. The protocol’s security depends on the quantum measurement guideline stating that quantum system measurement makes it collapse into the operator’s eigenstate corresponding to the measurement. Hence, eavesdropper learning activities such as carrying out measurements or transmitting information will be detected. The protocol gets implemented via quantum and classical stages (Mafu et al., 2022). Notes that the particular benefit of quantum cryptography entails its capacity to guarantee security, and past research has shown unconditional security of the BB84 QKD system (Zhang & Mao, 2020)
According to Sun & Huang (2022), depending on the general communication framework, the QKD system can get subdivided into a detector, decoder, channel, encoder, and source. The security requirement of every module for a decoy-state BB84 protocol includes Alice in the source and encoder, quantum channel, and Bob, the decoder and the detector. The source provides the needed optical pulse, weak coherent pulses, or single photon pulse for BB84 with various intensities. For instance, Alice, the encoder, changes the random classical bit, including the essential bit and information bit, into a quantum state performed by a modulator which remains the encoder module section that should be protected to eliminate the existence of Eve, the eavesdropper.
Eve should not possess any information concerning the random number used by Alice. The encoded quantum state must align with the standard quantum states according to the BB84 protocol, and no information or data should leak from the channel side. Alice’s quantum state is transmitted to Bob in the quantum channel, and the quantum channel should have lower noise and loss to enhance the practical QKD system performance (Sun & Huang, 2022). Moreover, Bob, the decoder, should measure the optical pulse from a quantum channel and change the quantum state into classical bits, including the basis and information bits. The encoder, Bob, should change the classical bits into quantum states for and back. The detector will absorb the photon, register the SPDS click, and ensure that no active electrical or optical signal is leaked to Eve and that the detector’s clicks are registered Bob (Sun & Huang, 2022).
Bibliography
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Mafu, M., Sekga, C., & Senekane, M. (2022). Security of Bennerr-Brassard 1984 Quantum-Key Distribution Under a Collective-Rotation Noise Channel. Photonics, 9(941). https://doi.org/10.3390/photonics9120941
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