Cryptography — The cornerstone of cybersecurity

Interview with Niklas Johansson, PhD, and Research Manager at Sectra Communications

Wanting to keep information secret and inaccessible to others is nothing new—cryptography is something we have used since ancient times. The reason is simple: if sensitive information falls into the wrong hands, it can have serious consequences.

Cryptography is something we use—and rely on—every day. For example, through electronic IDs, we can authenticate ourselves and carry out tasks that would otherwise require our physical presence—such as paying for parking or applying for a bank loan.

Why do we trust the cryptography that we use daily?

Cryptography is based on encryption algorithms, which provide the “recipe” for how to make the information unreadable for others but still retrievable for the intended recipient.

The security of today’s encryption algorithms is based on mathematical problems that we assume are difficult to solve. If the mathematical problem is difficult to solve, the encryption is difficult to break. However, there is no definitive proof that these problems are truly hard to solve—it is something we need to trust.

“There’s no security without trust, and that also applies to encryption algorithms. Trust in an encryption algorithm is built over time – as more people attempt and fail to find a simple solution to the problem, the confidence in the algorithm grows.” explains Niklas Johansson, PhD, and Research Manager at Sectra Communications.


quantum technology


One simple solution would cause security to fail

The security is compromised if a single person finds a simple solution. This occurred in the 1990s, when the mathematician Peter Shor found that a sufficiently advanced quantum computer would break most of the popular methods for authentication and exchanging cryptographic keys.

The natural way forward to address this issue, is to develop new algorithms assumed to remain difficult for a quantum computer to solve, and much progress has already been made in this area. However, trust must be built anew for these algorithms. There are also other ways to avoid the threat from quantum computers.

There’re already solutions that are secure, even if the adversary has access to a sufficiently good quantum computer. The challenge here is that they´re not suitable for all cases.

Niklas Johansson

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