What Is PostQuantum Cryptography?
What Is PostQuantum Cryptography?
Advancements in technology mean that more and more business processes are becoming digitalized every day. For this reason, businesses need secure technology that protects private data from prying eyes and criminals. Postquantum cryptography provides such protection through a combination of mathematical concepts, rule sets, and algorithms.
Postquantum cryptography (PQC) is also known as quantumresistant cryptography, and the main goal is to develop a secure system that operates with existing network and communication protocols. It is also important that the system is shielded against both quantum and classical computers as well. In turn, these systems ensure that their personal information and other information, such as communications, business processes, and transactions remain protected against unauthorized persons. What Does Quantum Represent?
In the early 1990s, scientists discovered that light is made of the smallest quant of energy, known as photons, giving rise to the quantum theory of light. In the same manner, one of the most wellknown experiments in science is the doubleslit experiment, where an individual points a beam at a plate with two parallel slits. Light passes through the apparatus, where it can be observed on a screen, and the photons create alternating bands of light and darkness called interference fringes. Interference fringes occur when two sets of waves overlap. If one wave crests onto another wave, constructive interference results. On the other hand, if a wave combines with a trough, destructive interference (darkness) results. Sometimes, only one photon passes through the apparatus, meaning that it passed through both slits at once.
Notably, a photon is found when the two waves constructively interfere. It would be difficult to find a photon in the region of destructive interference. Likewise, a case wave function collapse occurs during an experimental measurement. In fact, a collapse can arise whenever quantum systems interact or event spontaneously.
How Does Quantum Computing Work?
Postquantum provides the next generation of information security. It has sparked the development of a portfolio of cybersecurity tools while securing many multiparty computing systems. Quantum computing, on the other hand, helps computers overcome the many hurdles of traditional computing.
Quantum systems can exist in two independent states at once. Under these circumstances, particles interact on the smallest scale. Even though these particles follow the rules of physics, they often act in ways that seemingly contradict the rules as people traditionally know them to be. From another perspective, it is also possible that some of the rules are less applicable and more counterintuitive than scientists once thought.
The smallest unit of data in quantum computing is a qubit, not a bit. A qubit is like the spin of a magnetic field. Additionally, a qubit can be a pair of one or two states (0 or 1), although, unlike a bit, it is not just an on or off switch. At the quantum level, a qubit can be proportional to both states, a phenomenon also known as a “superposition.” Sometimes, it can be accurate at any position between 0 and 1.
Superposition is the amount of data that can be stored exponentially as the number of qubits increases. In general, one million values can be stored in a group of twenty qubits at once. However, quantum computing requires knowledge of further concepts, especially quantum complication, which allows dissimilar traditional computers to process data sequentially, and quantum computers to process data simultaneously.
Differences Between Algorithms and QuantumSafe Algorithms

Algorithms
An algorithm is a set of instructions given to complete a specific task. In computer programming, algorithms are frequently written as functions. For example, a video viewing application may include a library of functions that each use a custom algorithm to change the format or edit the video.

QuantumSafe Algorithms
These algorithms are based on different areas of mathematics. For example, it is thought that hashbased cryptography provides the most secure algorithms for digital signatures. These quantumsafe algorithms will be very easy to implement into different processes, devices, and networks. Postquantum algorithms, on the other hand, are practical for almost everything.
Approaches To Deploying PQC Algorithms
Much attention has been given to quantumresistant algorithms, particularly as the PostQuantum Cryptography competition of the National Institute of Standard and Technology (NIST) enters its last phase and IBM has announced its plan to build a 1,000qubit quantum computer by 2023.
The NIST has indicated that quantum computer design relies on new scientific concepts and that present, postquantum algorithms are developing different mathematical tools to resist quantum attacks, which is helpful for everyone, especially designers and analysts.
From Traditional to PQC Algorithms
Many organizations are working to create postquantum algorithms computers before massive scale quantum computers break the publickey algorithms. Many assume that both PQC and traditional algorithms will be used once people begin to trust the PQC algorithms and apply their security protocols.
Organizations should also keep in mind that upgrading Public Key Infrastructures (PKI) schemes will be very timeconsuming and that existing security rules must also be upgraded, which will be very timeconsuming as well.
Approaches To Migrating to PQC Algorithms
Two approaches may be used to migrate technology from publickey encryption algorithms to PQC algorithms:
 Two Certificates
Each certificate uses its own signature and public key. One certificate uses the traditional algorithms, while the other uses the PQC algorithms.
 One Certificate
On the other hand, with the onecertificate approach, there is a sequence of PQC and traditional keys, as well as a sequence of PQC and traditional signatures.
Both approaches require a set of rules that combine traditional and PQC algorithms for not only security purposes but also authentication purposes.
Key Derivation Function (KDF) should be used by both Internet Protocol Security (IPSec) and Transport Layer Security (TLS) to process the shared confidential information between the two inputs[SS=KDF(SSt,SSPQC)].
Likewise, the same or the double encapsulation should be used by the S/MIME for security and the parallel signatures for authentication.
What Are Challenges Faced in Developing PostQuantum Security Algorithms?
 Because postquantum cryptography is more complicated than other algorithms, a revolutionary, rather than evolutionary, approach is beneficial. Despite the advantages posed by postquantum security algorithms, there are important challenges that will impact the effectiveness of this technology. Size of the Keys
One of the main challenges has to do with the size of the keys]. Present signatures and encryption algorithms have keys merely a hundred or thousand bits long. Some of the suggested postquantum algorithm keys will be tens of kilobytes, and even up to a megabyte, in size, meaning that these keys must be stocked efficiently.
Public keys used in public key infrastructure or stored in devices provide more price bandwidth and memory. Because bandwidth requirements are likely to increase the use of these strategies, there will be large encryption text.

Processing & Computing
Similarly, the second major challenge has to do with the Internet of Things (IOT) devices, which have low processing and computing power. IOT devices are incredibly prevalent, so it is important that these devices are best equipped to handle quantum attacks.

Security Attacks
Finally, the third major challenge has to do with the security of new algorithms, particularly when it comes to classical and quantum attacks. Put simply, the mathematical computing behind the new algorithms has yet to be mastered, and how to secure suggested algorithms remains an open question at this time.