Disputas - Master of Science in Technology/Engineering Anders Tungeland Gjerdrum

Master of Science Anders Tungeland Gjerdrum will Friday October 30th at 12:30 PM publically defend his thesis for the PhD degree in Science.

Title of the thesis:

"Diggi: A Distributed Serverless Runtime for Developing Trusted Cloud Services"

Popular scientific abstract:

"The Cloud offers the convenience of outsourcing storage and processing power to a public shared environment. Physical infrastructure is managed by the cloud provider, allowing hosted applications to be deployed without any upfront investment. The cloud simplifies all aspects of hosting, ranging from software updates, failure management, and growth. Serverless is a natural continuation of this trend which narrow the scope of deployed software down to individual “functions”. Such “functions” are automatically deployed based on platform engagement and billed per unit of usage. Software hosted in a public cloud require that sensitive data such as user identifiable information be protected from unauthorized access. However, this model assumes that the underlying infrastructure can be trusted. Physical attacks on server hardware conducted by an unfaithful employee may compromise the integrity and privacy of hosted software entirely.  

Dedicated hardware modules such as a Trusted Execution Environment (TEE) mitigate attacks by enabling separate secure application environments, protected from inspection by the untrusted underlying system. Intel SGX introduces one such system implementing support for hosting secure software (enclaves) on hardware found in most Intel-based CPUs released after 2015. The correct behavior of this software may be verified remotely through program attestation. 

SGX is designed to protect software from multiple techniques employed by an attacker to attempt to compromise its security. This leads to a complicated hardware design which may impact the capability and responsiveness/performance of software within.  

This thesis presents the design and implementation of Diggi; an efficient trusted cloud function runtime implemented in SGX. Diggi enables the development of secure applications, composed of multiple persistent and accountable cloud functions which may be jointly authenticated through co-attestation. We demonstrate that the design of Diggi is practical, and additionally, that it reduces the overhead of SGX compared with standard runtime execution techniques. We further demonstrate the applicability of Diggi by implementing two pseudo-real application workloads demonstrating a database management system and a machine learning inference pipeline on top of the Diggi runtime."

The thesis is published in Munin and is available at: https://hdl.handle.net/10037/19607



  • Professor Dag Johansen, Department of Computer Science, UiT (main supervisor)
  • Principal research scientist Robbert Van Renesse, Cornell University, USA
  • Researcher Håvard D. Johansen, Department of Computer Science, UiT



Evaluation committee:

  • Senior Lecturer Hamed Haddadi, Dyson School of Design Engineering, The Faculty of Engineering, Imperial College London, United Kingdom (first opponent)
  • Associate Professor Leander Nikolaus Jehl, Department of Electrical Engineering and Computer Science, Faculty of Science and Technology, University of Stavanger (second opponent)
  • Professor Randi Karlsen, Department of Computer Science, UiT (internal member and leader of the committee)

Reserve member : Associate Professor Dilip K. Prasad, Department of Computer Science, UiT.

Both opponents will participate remotely to the defence.

Leader of the public defense:
The leader of the public defense is Professor Arne O. Smalås, Dean, Faculty of Science and Technology, UiT.

Opposition ex auditorio:
If you have any questions for the candidate during the public defence, please send an e-mail to the leader of the public defence. They will announce the questions during the defence.


Trial lecture:

The trial lecture is held Friday October 30th at 10:15 AM in the same auditorium.

Title of the trial lecture: «TEEs for Blockchain»



The defense and trial lecture will be streamed via Mediasite: https://mediasite.uit.no/Mediasite/Catalog/Full/6cb328eda8874e179db699cefb6ec7bc21


UiT follows the national guidelines regarding infection control. A maximum of 20 people are allowed in the auditorium during the defence, as long as everybody keeps a distance of 1 meter at all times.

Få utskriftsvennlig versjon ved å trykke på denne
Når: 30. oktober 2020 kl. 12.30–15.30
Hvor: Auditorium 1.022, Teknologibygget
Studiested: Digitalt, Tromsø
Målgruppe: ansatte, Studenter, gjester / eksterne, inviterte
Kontakt: Marie-Josée Haglund Halsør