Quantum and Post-Quantum Cryptography

Recent years have prompted research into

quantum computers. Quantum computers have been the subject of controversy due

to their abilities to solve complex mathematical phenomena that have been

primarily developed as the basis of information encryption .Given that these

large quantum computers are built, they shall inevitably compromise the key

cryptosystem that is currently in use. This would jeopardize the

confidentiality presently enjoyed by digital communication and internet users

worldwide. The primary objective of post-quantum cryptography is to create

cryptographic systems that can interoperate with existing communication

protocols. This paper shall look into common cryptographic topics and reflect

the effect of post cryptographic quantum computing on common information

encryption.

Quantum key distribution

Quantum key distribution is indeed a

successful application to cryptography, quantum information that utilizes the quantum

mechanics theory to secure data (Quantum.ukzn.ac.za.). Quantum key

distribution generates a random key between two points over an insecure

network. Quantum key distribution is founded the superposition principle and

the Heisenberg’s principle. A one- time

pad encryption scheme is created and implemented using the securely distributed

quantum key. A great protocol of quantum

key distribution is the “BB84” protocol in which single qubits are

chosen randomly from {???, ???, ???, ???} states and sent. For QKD

the key used for encryption should only be used once. This removes the chances

of prediction from an eavesdropper or from the sender/receiver. Hence Quantum

key distribution guarantees integrity over an insecure channel unlike in

post-quantum cryptography whose key algorithms’ security rely on tough

mathematical problems and the capability of a quantum computer, one that ideally

runs Shor’s algorithm, to solve them these problems.

Symmetric cryptography & Symmetric key

management systems and protocols

Cryptography

involves the process of making messages non-readable by encypting them with

different algorithms. Cryptographic algorithms are grouped into two types of

encryption: symmetric and asymmetric encryption.In Symmetric encryption a

single key is used for the encryption and decryption proccess.

A crucial problem that

lies in symmetric key cryptography is the distribution of the secret key. The

key distribution must happen secretly. However key sharing can happen in one

some ways; a trusted third party could get involved in sharing the key with the

recipient. Alternatively, the sender can physically deliver the key to the

receiver. If the sender and reciever have previously used a key, they can

communicate the new key through encryption using the old key. Nonetheless this

option of distribution is hazardous because of the fact that an eavesdropper

can gain access to the old key and acquire the new key by intercepting

communication of the new key

Hash functions

A cryptographic hash

function receives a message as input and produces what is known as a message

digest of predetermined fixed length. One property of a cryptographic hash

function is that the digest from the hash function for any given message is impossible

to compute for those with a given hash. Another property of the cryptographic functions

have is uniqueness There are collisions of hash functions put the probability

is low 1?e/(?k(k?1)/2N). However with the development of quantum computers, it

is very likely that using the hash value, the initial message could be computed

and derived successfully. This would in a high magnitude compromise the

integrity of information passed over an insecure channel. Other practical

applications that use hash functions such as digital signatures and

authentication also face an integrity threat following the development

post-quantum cryptography.

Public key

cryptography

Public key

cryptography also known as asymmetric encryption uses two non-identical for

communication. The two keys involved are a public and a public key. Each of

these two keys have different roles; the public key encrypts the message while

the private key decrypts the message. Private keys can however not be computed

from public keys. Public keys are therefore shared hence allowing users a

convenient content encryption platform. Given that the public keys have to be

shared for decryption and encryption to take place , they are therefore stored within

digital certificates to facilitate structured and secure sharing among

communicators. Users, therefore, have them at their disposal for encryption

during information sharing. However, only the users of private keys can decrypt

the information.

Shor’s algorithm

Shor’s

algorithm was developed by a mathematician known as Peter Shor. His innovation

brought about a quantum algorithm for integer factorization. All it takes is one post cryptography quantum

machine with enough qubits to solve quantum gates for 0((log N) 2(log log N) (log log log N)). For this reason, therefore, these quantum computers can

break public key cryptography which is based on Shor’s algorithm. The public key encryption is pegged on a

principle huge numbers are computationally impractical. This phenomenon is however only valid for

classic computers. The development of quantum computers withstanding, software

developers need to reach common ground with mechatronic engineers in developing

computing systems that shall not compromise the integrity of information

reliance and computing.