Professor of Computer Science Valtteri Niemi has dedicated his professional career to cryptography and cybersecurity.
A mathematically gifted young man applied to university, believing that mathematics had already yielded all its secrets. He soon discovered otherwise, and in 1989 Valtteri Niemi defended his doctoral thesis in theoretical computer science at the University of Turku's Department of Mathematics.
In his own words, Niemi's career has taken him from theory to practice and back again. His studies in mathematics led him to explore formal languages, that is, strings of symbols joined together according to defined rules. This area gave him a strong grounding and sparked his interest in cryptography, which is the study of encrypting or otherwise concealing meaning.
Since then, Niemi's career has centered on cryptography. It provides methods for securing communication over mobile networks and enables authentication in online banking. Cryptography protects information by rendering it unreadable to outsiders.
Groundbreaking work to safeguard mobile networks
Niemi pursued both research and teaching, first as an associate professor at the University of Vaasa's Department of Mathematics and Statistics from 1993 to 1997, and later as a professor of mathematics at the University of Helsinki from 2012 to 2015. He has served as a professor of computer science at the University of Helsinki since 2015.
Between his academic appointments, Niemi worked on practical information security applications at the Nokia Corporation. Over 15 years he developed and assessed a wide range of solutions, focusing particularly on the security, cryptography and privacy of mobile phone networks. He contributed significantly to the development of security standards for 3G and 4G networks and chaired the security working group of the standardisation organisation 3GPP from 2003 to 2009.
"Standardisation plays a vital role in safeguarding the information security of mobile networks. Because phones are made by different manufacturers and function entirely independently, we rely on strict, uniform standards to protect data," he says.
"The challenge in securing radio traffic lies in not only preventing eavesdropping, but also shielding user identities and location details. Standardisation helps minimise opportunities for outsiders to monitor communications."
Niemi's work at Nokia resulted in a number of patents that became essential to mobile phone standards. Over his career, he has contributed to over 50 patent families and patents.
"Two of the patents later featured in the 2009 patent dispute between Nokia and Apple when Nokia filed a lawsuit initially based on 10 patents."
At the University of Helsinki, Niemi has developed cybersecurity and cryptography teaching, supervised theses, and led the Secure Systems research group on information security and networks.
A cat-and-mouse game of information security
As a discipline, information security has continued to fascinate Niemi, inspiring over 100 scholarly publications as fresh challenges keep arising.
"We close one gap, and another appears."
Cryptographic systems began to be studied openly in the 1970s, and the advent of the internet heightened the civilian need to protect telecommunications.
"Current protection methods aren't based on keeping the method itself secret. Only a small element is concealed: much like a key to a lock that only a specific person holds.
"The overall principle can be public as long as the essential secret is safeguarded."
In research, some work to build security, algorithms and protocols, which others attempt to compromise. Research must balance both defence and offence.
Currently, information security is under pressure from AI-driven hoaxes, such as social engineering and phishing, in which attackers pose as reliable organisations, such as banks or government authorities.
"Hoaxes are becoming increasingly sophisticated and harder to detect."
Finding the sweet spot between security and usability
Many of the challenges in information security have, in theory, been solved long ago. In practice, however, implementing these solutions can be slow and complicated.
"Although we have several theoretical approaches to securing information, practical solutions must also make people's lives easier. The aim is to minimise costs, while maximising both usability and security.
"Passwords, for instance, remain widely used. And I can't be the only one frustrated by two-step authentication, which always has me scrambling for my phone. The ideal balance between security and usability has yet to be found."
What might it look like?
"It would require some kind of agent on the user's side. Crucially, the agent would need to be genuinely acting for the user, not for, say, the major mobile-device manufacturers. It could guide people on what they should and shouldn't do, keeping a watchful eye on their behalf."
Professor Niemi delivered his farewell lecture at the University of Helsinki on 31 October 2025. What will he do when he retires?
"I'm still involved in a few research projects, and there's an ongoing funding call as well, focusing on topics such as the information security of 6G technology," Niemi explains.
Outside of work, he plans to spend time woodworking (pressure-treated wood only) and golfing.
