Cybersecurity
Post-quantum: Why crypto agility is so important
Quantum computers are considered the next technological revolution. However, they pose a challenge for IT security: The transition to „post-quantum cryptography“.
09.10.2026
What is quantum computing?
Conventional computers work with bits, while quantum computers use “qubits”, which can exist in multiple states simultaneously. This opens up multidimensional possibilities and enormous computing power.
For now, quantum computers are still confined to laboratories and experimental environments. Test setups from the University of Stuttgart were already on display at AEB's annual internal TechSummit. Dr. Stephan Welte, director of the Quantum Network Node, and his PHD student Raphael Benz were on hand to answer questions and offer insights into the future. One thing is certain: For many applications, conventional computers will continue to be the better choice. In certain scenarios, however – such as optimization, simulation, and cryptography problems – quantum computers could demonstrate their decisive advantage. At the same time, they pose a major challenge for IT security professionals: Quantum computers will undermine many of the encryption methods in use today. Therefore, preparations for the transition to quantum-secure methods must begin now.
Security at AEB
Availability, confidentiality, integrity – these are AEB's top security objectives. We provide information on this in our Trust Center
How is IT security affected?
Much of today’s data security relies on cryptographic methods such as RSA. Their security is based on the difficulty of factoring very large integers into their prime factors. These integers are generated using so-called one-way functions. At present, there is no known classical computer capable of factoring a 4,000-bit number. That's going to change. Even the Discrete Logarithm Problem (DLP) would then no longer be able to protect digital signatures. With the quantum algorithms introduced in 1994, mathematical problems on which today's cryptographic methods are based will be solvable with the appropriate powerful quantum computer.
In short: Current HTTPS connections, VPN access, digital certificates, and key exchange methods are no longer secure in the quantum era.
Where do the risks lie?
Two scenarios from the „Cryptography and Quantum Computing“ market survey by KPMG and BSI illustrate the implications of "post-quantum".
- Confidentiality: For example, if highly confidential information – such as production processes – is sent using public-key cryptography and is decrypted by an attacker, that attacker could read the information unnoticed and quickly use copies to offer a cheaper competing product on the market.
- Authentication: For example, if an attacker manages to gain access to the private key of a root certificate authority, that attacker could issue any certificates as trustworthy. This would make attacks such as counterfeit access cards possible.
A particularly critical issue is the approach taken by attackers known as "store now, decrypt later". Attackers collect encrypted data today and store it for years. Once sufficiently powerful quantum computers become available, this data could potentially be decrypted later. The question, therefore, is not only what data needs to be protected today, but also what information should still be considered confidential in ten or twenty years.
Is the entire field of cryptography under threat?
No. Symmetric algorithms such as AES are considered relatively robust even in the quantum age. Although quantum algorithms can theoretically compromise their security, this can be offset by using longer key lengths. In addition, governments and companies around the world are working to implement post-quantum cryptography (PQC). Approaches include code-based, lattice-based, and hash-based cryptography.
How does AEB deal with the topic of security?
The question of when powerful quantum computers will become available is becoming increasingly secondary. What matters is migrating to quantum-safe cryptography in time. That is why AEB has already taken the steps in this direction, as security has been one of the cornerstones of the AEB Cloud and software development for many years.