Quantum computers pose a potential threat to traditional cryptography. Cryptography will need to adapt, but how agile is our digital security?
2025 is primarily the year of AI agents, but also a bit of quantum computers. Important technological breakthroughs are opening the door for quantum computers that are sufficiently reliable and scalable for real work. The academic world estimates that the first “usable” quantum computers are only a few years away from us.
Enthusiasm around quantum computers is accompanied by caution. Quantum computers can be a powerful weapon if they fall into the wrong hands. Digital security must therefore brace itself now. The key lies in migrating today’s cryptography to quantum-resistant standards. That’s easier said than done, we learn from Dr. Kristof Verslype, cryptographer at Smals Research, during Cybersec.
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Cryptography in (Post-)Quantum Times: Fast Cheetah or Slow Sloth?
Cute Babies
Cryptography plays an invisible yet indispensable role in the digital fabric of society. Every piece of technology, from physical hardware to digital services, is equipped with cryptography to secure data. Encryption is literally the lock on the door: data is converted into text unreadable to humans and secured with a secret cryptographic key.
Today’s common encryption standards, especially those based on RSA and elliptic curves, have proven reliable for decades. That threatens to change. “Encryption keys that are unbreakable for traditional computers could be cracked by powerful quantum computers in just a few hours. Now quantum computers are still cute babies, but they will grow up to be dangerous warriors. Without secure cryptography, our society collapses,” warns Verslype.
This is no longer a future problem. Organizations must be aware today that their data will not be safe forever. Verslype: “Attackers could already intercept encrypted communication and later decrypt it with a quantum computer. Communication is the most critical application area for quantum-resistant cryptography”.
Fortunately, the sector is not standing still. The American NIST has been working for years on the search for post-quantum cryptographic standards. That this is not self-evident became clear in 2022 when SIKE, one of the finalists for such a ‘quantum-safe’ protocol, was cracked by a ten-year-old Intel PC, which woke up everyone in the security world.
Quantum computers are still cute babies now, but will grow up to be dangerous warriors.
Dr. Kristof Verslype, cryptographer Smals Research
Crypto Migrations: not a One-Time Shot
Over the years, new encryption standards have been adopted multiple times. DES, for example, made way for AES at the beginning of this century, which is less vulnerable to the quantum threat in the short term. Verslype looks back: “The previous crypto migrations were slow, cumbersome, and expensive. It takes an average of five to fifteen years to fully migrate. New standards are constantly being developed because there must be alternatives when a standard is cracked. ‘Quantum-ready’ is not a one-time shot“, says Verslype.
Verslype advocates biting the bullet and preparing now for the step towards quantum-resistant cryptography, if necessary in multiple steps, as the German agency for digital security proposes. BSI advocates a hybrid approach where contemporary and post-quantum cryptography are used together until post-quantum cryptography is reliable.
“This leads to more migrations and more complexity”, Verslype believes. “Cryptography is an asset that needs to be managed. In practice, this is barely done. We must accept that standards have a lifecycle and act accordingly to manage them in a mature way”.
Insight, Policy, and Agility
Verslype identifies three steps that lead to what he describes as crypto maturity: the ability to quickly transfer systems to newer standards. “The first step is insight into what you use. Create an inventory of what form of cryptography is applied where and for what purpose. That brings you to step 2, where you determine a policy on what to use and what not to use anymore.”
“The inventory also helps you respond faster to vulnerabilities, or to demonstrate compliance”, Verslype continues. “However, you must constantly keep the inventory and your policies up-to-date. Start with your most important assets and consolidate what you already have. Initially, this may require a lot of manual work, but in the long term, you can automate the process”.
Next, it’s a matter of migrating the cryptographic mechanisms that no longer suffice to newer standards. Building in flexibility or “crypto agility” facilitates migration without affecting the availability of systems: a crucial criterion for Verslype.
“End-users place great importance on availability. You must be able to add, remove, or modify cryptographic functions in real-time and at runtime. The migration can also lead to performance issues: so thoroughly test first if your infrastructure can handle it.”
Sepia
Verslype illustrates with an example from their own stable. Sepia is a system for sending and electronically signing documents, developed by Smals. Verslype shows a visual representation of how Sepia’s architecture, which is already live today, offers a level of crypto agility. Among other things, the cryptographic keys are stored in a centralized system.
Our end-users are often slower to adopt new standards, and overly strict rules could make the services practically inaccessible. Therefore, good management of crypto policies, including potential exceptions, is necessary.”
“Crypto resilience implies centralization and automation. Building in resilience costs money, but saves you more in the long run. It can go hand in hand with cost efficiency”, says Verslype.
5 Levels
Those who hoped for a ready-made guide to becoming “crypto-agile” will be disappointed by Verslype. “There is no official roadmap yet. Agility is a gradual process, with many hurdles and challenges. Smals embraced cryptography at an early stage, but there’s still a long way to go for us too. Being crypto agile is harder than being quantum ready”.
The CAMM model (Cryptographic Agility Maturity Model), developed in 2023 by the University of Darmstadt, comes closest to a roadmap. It distinguishes five levels of crypto resilience. If you’re at level “zero”, it’s quite hopeless. “Migration is not even possible due to hardware or software limitations, for example”, says Verslype.
The model builds further from level one to level four. The lower you are on the ladder, the more difficult the migration will be and the more preparatory work will be required. Only from level three onwards does the migration proceed in a safe and efficient manner. Level four is the highest distinction and implies “rapid migration at an organizational level”, according to Verslype.
Being crypto agile is harder than being quantum ready.
Dr. Kristof Verslype, cryptographer Smals Research
Cheetah
At the end of his presentation, Verslype primarily wants to encourage the audience to take action. “The path towards cryptographic agility is a long journey. We’re still at the beginning, but it will pay off in the long run. With crypto agility, you’re laying the foundation today to be ready for cryptographic challenges in the future.”
Verslype concludes with a comparison from the animal kingdom: “Crypto-agile systems are like a cheetah: fast, flexible, and agile. I can only urge everyone to embrace it and become like a cheetah.”
This editorial contribution was created in collaboration with Smals.