Page 37 - Cyber Defense eMagazine September 2025

P. 37

Shor’s Algorithm

Why are cybersecurity professionals so scared of quantum threats? The reason traces back to the Shor
Algorithm. In 1994, Peter Shor, an American theoretical computer scientist, discovered an algorithm. The
purpose of this algorithm was to accelerate the factoring of large numbers.

This development was a problem.

Computers that are commonly used today are hard-pressed to factor huge numbers. This is why modern
encryption systems work. Cybercriminals are unable to break down huge combinations into prime
components. On the other hand, the Shor algorithm can do this easily, provided it does so on a quantum
computer. This algorithm can break asymmetric encryptions that are popularly used today.

The lesson from the Shor algorithm is clear: start preparing today for quantum threats.

What are Quantum Threats

Today, we are using high-performance computer systems to get our work done. However, in
technological terms, these are still ‘classical’ computers from a quantum perspective. The high-
performance computing prevalent today will soon evolve into quantum computing. Such computation
leverages the frameworks of quantum mechanics to solve complex problems. While classical computers
use bits, quantum computing works with qubits. The framework leverages different quantum phenomena
to work on multiple possibilities simultaneously.
Complex calculations, the backbone of encryption, can thus be solved quickly.

Why does quantum computing present a cyber risk?

Traditional or classical computers cannot process information quickly. But quantum computers can. This
fact means existing encryption methods can be cracked easily. Your organization might pride itself on
using robust encryption and following encryption best practices. But, enter quantum computing, and
critical digital information won’t be safe anymore.

Here are some of the risks of quantum computing, or to be specific, quantum threats:

• Obsolescence of Public Encryption

Some of the common types of encryption we use today include RSA (Rivest-Shamir-Adleman), ECC
(Elliptic Curve Cryptography), and DH (Diffie-Hellman Key Exchange). The first two are asymmetric types
of encryption. The third is a useful fillip to the first to establish secure communication, with secure key
exchange. RSA relies on very large integers, and ECC, on very hard-to-solve math problems. As can be
imagined, these cannot be solved with traditional computing. However, the time is not far when public-
key encryption methods will be rendered obsolete via quantum computing.

32 33 34 35 36 37 38 39 40 41 42