Explaining Quantum Computing (and Why the Mainframe Is Ready for It)
Jim Zell, Distinguished Engineer and VP of U.S. Core Enterprise & zCloud Practice at Kyndryl, explains the basics of quantum computing and the mainframe's role in securing data against quantum threats
In Season 10, Episode 5 of the TV show “Bones,” forensic anthropologist Dr. Temperance Brennan wanted to open a speech she was going to make with a joke, so she runs her idea by her FBI partner, Special Agent Seeley Booth. It goes like this:
“Erwin Schrödinger gets pulled over by the police for speeding. The officer says, ‘What’s in the trunk?’ Schrödinger says, ‘A cat.’ The officer says, ‘Well, I need to see.’ So, the police officer opens the trunk. He says, ‘This cat is dead.’ Schrödinger says, ‘Well, it is now.’”.
Isn’t that a comedic masterpiece?
The joke, of course, falls flat—at least for anyone unfamiliar with Erwin Schrödinger and quantum mechanics. Schrödinger was an Austrian theoretical physicist and one of the founders of quantum mechanics. He is best known for his “Schrödinger’s cat” thought experiment, which imagines a cat sealed in a box that is simultaneously alive and dead until someone opens the box and observes it. The scenario was designed to illustrate quantum superposition: the idea that a system can exist in multiple states at once until it is measured—or, in the case of Brennan’s joke, until the trunk is opened.
With Opportunity, Comes Risk
As absurd as that sounds, the paradox captures a real principle at the heart of quantum physics—and, by extension, quantum computing. Just as Schrödinger’s cat can exist in a superposition of states until measured, a quantum bit, or qubit, can exist as both 0 and 1 simultaneously.
That counterintuitive property is what makes quantum computers fundamentally different from the classical machines we use today. This fundamental difference is key to a technology that represents great opportunity for businesses, but also risk.
IBM has positioned its mainframe to address these challenges. However, to understand how the mainframe is prepared for the risks of the quantum era, we must understand the principles of quantum computing. What follows is a clear, easy-to-understand explanation of quantum, the advantages it promises and the business impact that executives should already have on their radar.
A Fundamental Difference
Classical computers range from the laptops we use for everyday tasks, to the mainframes we use for mission-critical workloads, to the supercomputers capable of performing trillions of floating-point operations per second (FLOPS). Despite the vast differences in how these computers are used, they all store and process information the same way, using bits that exist in one of two states: on or off (1 or 0).
Quantum computers are fundamentally different from classical computers. Instead of storing information as bits (0 or 1), they use quantum bits, or qubits. The key difference is that a qubit is not limited to just 0 or just 1. They can exist as 0, as 1, or in a combination of both at the same time. This property is called superposition.
Explaining why this happens belongs to a physics course, but the idea can be illustrated by the famous double-slit experiment. When light passes through two narrow slits and hits a screen, you might expect to see two bright spots corresponding to the two openings. Instead, you see a pattern of multiple light and dark stripes.
This happens because light behaves like a wave. As the waves pass through each slit, they overlap and interfere with each other. Where the waves reinforce each other, you see bright bands. Where they cancel each other out, you see darkness. The pattern on the wall is the result of this interference.
What makes the experiment even more surprising is that light also behaves like a particle. It exhibits both particle-like and wave-like properties. This wave-particle duality is one of the foundations of quantum mechanics and helps us understand how something can exist in multiple states at once.
Why Does This Matter?
Quantum computers harness two key principles of quantum mechanics: superposition and entanglement.
Superposition allows qubits to represent multiple possible states simultaneously. Instead of checking solutions one at a time like a classical computer, a quantum computer can explore many possibilities at once.
Entanglement is another remarkable phenomenon. When qubits become entangled, the state of one qubit is directly correlated with the state of another, even if they are separated by large distances. Changing one immediately affects the other. This deep connection allows quantum computers to coordinate information in ways classical systems cannot.
Together, superposition and entanglement enable quantum computers to solve certain types of problems far more efficiently than classical machines. These include simulating complex molecules, optimizing large logistical systems and factoring very large numbers used in cryptography.
Quantum computers are not simply faster versions of classical computers—they compute in a fundamentally different way.
Business Impact
Quantum computing presents a dual business reality: significant opportunity on one hand and meaningful risk on the other. First, we’ll explore the transformative advantages quantum technologies may unlock. Then, we’ll examine the challenges they introduce
Transformative Advantages
The broad functional capabilities of quantum computing can be grouped into four main categories: computational acceleration, complex system simulation and modeling, secure information capabilities and ultra-precise measurement.
Each industry will have its own set of applications, often extending well beyond these four categories. For example, in the financial industry, computational acceleration enables use cases such as portfolio optimization, asset allocation modeling, credit exposure analysis and option pricing. Other impacted areas are supply chain optimization, manufacturing production scheduling, power grid distribution optimization, GPS navigation and acceleration of machine learning and AI.
The business impact of quantum computing is imminent, making it critical to engage with this technology now—early adoption can provide a competitive edge before the advantages become widespread. For instance, the Swiss pharma company, Roche, partnered with Cambridge Quantum Computing in 2021 to focus on applying quantum chemistry algorithms to Alzheimer’s disease research, studying molecular interactions that are difficult for classical computers to perform.
In 2024, Toyota partnered with Xanadu, a leader in quantum computing, to advance materials science simulations that could lead to better sensors, electronics and other car components. Just this year, Cisco and Qunnect built a quantum network using New York fiber optic cables.
Quantum Challenges
Business growth is what we all strive for, and quantum can create new opportunities and revenue streams for companies across all business sectors. However, how to do this is not exactly clear.
Quantum technology is immature, and many will find it difficult to come up with solid, actionable use cases. Plus, talent is quite scarce. The same could be said of other unreliable, niche-oriented, initially ignored innovations like the internet, smartphones, cloud computing, AI and machine learning, 3D printing, GPS and blockchain.
It’s not like you can go out and purchase a quantum computer and start testing. Access is limited, and at present, owning one is prohibitively expensive. Just as AI can render current business models obsolete—think chatbots and virtual assistance replacing call centers, and AI design tools for apparel furniture, architecture, marketing or any writing task—Quantum has the same potential.
Security and Data Privacy at Risk
Perhaps the most impactful challenge is cybersecurity and data privacy. Those algorithms we have relied on for a long time will become less useful once quantum computers become ubiquitous. To explain this, you must understand that most of today’s encryption uses algorithms you have likely heard about, like RSA, Elliptic Curve Cryptography (ECC), and Diffie-Hellman.
Current encryption is based on the difficulty of factoring large numbers or solving discrete logarithms. These algorithms would take a classical computer at least millions of years to crack RSA-2048 encryption. RSA encryption is used for encrypting pretty much everything we see and touch daily. Currently, it is effectively unbreakable.
To crack the most advanced encryption we have today, you still need an algorithm and a more advanced quantum computer than is currently available. The quantum computers are coming, and the algorithms to do just this were developed in the 90’s.
Algorithms to factorize large integers efficiently and for searching unsorted databases or solving optimization problems were developed by Peter Shore and Lov Grover. Shor is a mathematician and quantum scientist who developed Shor’s algorithm for factoring large numbers on a quantum computer. Grover is a computer scientist who invented Grover’s algorithm for quantum search acceleration.
Why the Threat Is Now
The problem isn’t what we will do when someone develops algorithms that a quantum computer can exploit. The problem businesses need to consider is this: What happens if you have data stolen today that is decrypted later, when those algorithms are put in use on a quantum computer? That is what everyone calls the quantum problem—data stolen quietly today and decrypted, say, 10 years from now.
In this “harvest now, decrypt later” model, envision quantum brute force attacks or cryptanalytical attacks on already-harvested data. The unbreakable encryption today could be broken by a quantum computer in days, maybe hours. Now imagine what this means for private communications, medical records, intellectual property, financial data or military satellite communications that are stolen today.
The Mainframe’s Reaction
What would be helpful for this potential disaster would be the ability to use different algorithms that would prevent my data from being quantum decrypted, a quantum-safe algorithm. Well, those are available now.
Certain Microsoft environments now include post-quantum cryptography APIs; some Cisco routers and switches offer quantum-safe secure boot and firmware validation. And then, there is the mainframe.
IBM’s mainframes process a staggering number of financial transactions daily—approximately 87% of all credit card transactions globally—and handle massive volumes of non-financial data such as healthcare records, government workflows and enterprise logistics. The IBM z16 was the first mainframe system protected by quantum-safe technology across multiple layers of firmware. This means that z16 firmware and the secure boot process are protected against some quantum attacks out of the box.
To help protect clients’ sensitive data, IBM introduced the Crypto Express8S card. It is a hardware security module (HSM) that allows applications to get access to the quantum-safe algorithms. IBM Crypto Express8 will be useful for application modernization and for building new applications. The card allows clients to leverage both quantum-safe and classical cryptography. The same technology is also on the z17.
Secure Boot is the mechanism that verifies the integrity of code being loaded, before it’s allowed to execute. The secure boot process includes checking code for the proper signature by an approved signer. The z16 also uses a quantum-safe mechanism that leverages a dual-signing scheme which includes both quantum-safe and classical crypto algorithms. The dual-signing scheme helps ensure the authenticity of the firmware that is launched on the system. This helps defend against ransomware attacks that attempt to inject malware into the bootup process.
Advice for CIOs
Treat quantum as a strategic planning item. Start by taking inventory of critical systems and sensitive data, identifying where you have potential “harvest now, decrypt later” vulnerabilities.
Prioritize and assess your current crypto stack and map out where you should integrate quantum safe. Add another work stream to engage your vendors and understand their capability. Build a migration road map. Lastly, stay ahead of this.