Now showing items 21-40 of 58

    • Formal verification of the Norwegian Internet Voting Protocol 

      Slågedal, Solvei (Master thesis, 2018)
      In this paper we look at the formalization and verification of several security components of the cryptosystem underlying The Norwegian Internet Voting Protocol. The focus will be on vote submission and B-Integrity.
    • Fully Homomorphic Encryption 

      Sperre, Harald Elias Bjerke (Master thesis, 2017)
      In this paper we consider fully homomorphic encryption based on the learning with errors problem. We present the problem as introduced by Oded Regev in 2009 and explain a simple public key cryptosystem based on it. We show ...
    • Fully Homomorphic Encryption 

      Galteland, Herman (Master thesis, 2015)
      I 2009 presenterte Craig Gentry det første krypteringssystemet som klarte å utføre vilkårlig mange homomorfe operasjoner, og i prosessen lagde han også en framgangsmåte på hvordan man konstruerer et slikt system. I denne ...
    • Fully homomorphic encryption with applications to electronic voting 

      Strand, Martin (Doctoral theses at NTNU;2018:33, Doctoral thesis, 2018)
    • Hardness of Lattice Based Cryptography 

      Tunge, Thor (Master thesis, 2018)
      In this thesis we will discuss hard computational problems in lattice theory and relate them to cryptographic constructions. Many of these problems enjoy average-case hardness which makes them attractive for cryptography. ...
    • Hash Proof Based Encryption Schemes in EasyCrypt 

      Solberg, Morten Rotvold (Master thesis, 2018)
      We describe the basics of the proof-assistant \EasyCrypt{} and explain how to use \EasyCrypt{} to model encryption schemes and game-based security proofs. Furthermore, we analyze a generic encryption scheme by Cramer and ...
    • Highly Efficient Key Exchange Protocols with Optimal Tightness 

      Cohn-Gordon, Katriel; Cremers, Cas; Gjøsteen, Kristian; Jacobsen, Håkon; Jager, Tibor (Journal article; Peer reviewed, 2019)
      In this paper we give nearly tight reductions for modern implicitly authenticated Diffie-Hellman protocols in the style of the Signal and Noise protocols, which are extremely simple and efficient. Unlike previous approaches, ...
    • Identity Protection, Secrecy and Authentication in Protocols with compromised Agents 

      Båtstrand, Anders Lindholm (Master thesis, 2009)
      The design of security protocols is given an increasing level of academic interest, as an increasing number of important tasks are done over the Internet. Among the fields being researched is formal methods for modeling ...
    • Improving on the Number Field Sieve 

      Ørke, Per Kristian (Master thesis, 2015)
      We look at efficient methods for computing logarithms in finite fields of any type. To achieve this, we first develop methods for factoring integers and computing discrete logarithms in fields of prime order using algebraic ...
    • Improving the Norwegian Internet Voting Protocol 

      Øberg, Marianne Wiik (Master thesis, 2011)
      We have in this thesis looked at possible improvements with respect to security for the Norwegian Internet voting protocol. We have made a new protocol with independent secret keys, where all the encryptions of the votes ...
    • Index Calculus Attacks on Hyperelliptic Curves 

      Rasmussen, Lars Lone (Master thesis, 2009)
      Hyperelliptic curves could be considered against elliptic curves for cryptography by virtue of using smaller fields and therefore being faster, but they have several weaknesses. Index calculus attacks are effective against ...
    • Isogeny Based Cryptography 

      Strand, Trym (Master thesis, 2019)
      Vi undersøker hvor brukbart tre forskjellige kryposystem er in en post-kvantum verden. Rostovtsev-Stolbunov offentlig nøkkel protokollen, som bruker isogenyer mellom elliptiske kurver, viser seg å være usikre mot ...
    • Malicious cryptography 

      Galteland, Herman (Doctoral theses at NTNU;2020:116, Doctoral thesis, 2020)
    • Malware, Encryption, and Rerandomization - Everything is Under Attack 

      Galteland, Herman; Gjøsteen, Kristian (Journal article; Peer reviewed, 2017)
      A malware author constructing malware wishes to infect a specific location in the network. The author will then infect n initial nodes with n different variations of his malicious code. The malware continues to infect ...
    • Masteroppgave i kryptografi 

      Sigfusdottir, Gudrun (Master thesis, 2015)
      In this paper we look at the use of bootstrapping and squashing in order to make an encryption scheme fully homomorphic. The focus will be on what this is and how it can be used. The main focus will be on how this is applied ...
    • Mixnets and Verifiable Shuffling 

      Damsgård, Åshild Bryn (Master thesis, 2018)
      In this thesis we consider different mix network protocols. First, we discuss a protocol called cMix. We describe the concept of verifiable shuffling, that enable mixnodes to prove that they operate correctly according to ...
    • Modelling Oblivious Transfer in EasyCrypt 

      Furuberg, Mikkel Langtangen (Master thesis, 2018)
      We describe how to construct an oblivious transfer protocol which security is based on subset membership problems and smooth projective hash functions. A specific protocol based on the two-message oblivious transfer protocols ...
    • Multivariate Quadratic Cryptosystems 

      Milne, Simon Alexander (Master thesis, 2019)
      Vi beskriver egenskapene til multivariate ligningssystemer, og både egenskapene til Grøbnerbaser, og hvordan man beregner dem. Videre beskriver vi to multivariate kvadratiske kryptosystemer, kryptosystemet Matsumoto-Imai ...
    • Number Field Sieve 

      Spaans, Ruben Grønning (Master thesis, 2013)
      The Number Field Sieve (NFS) is the fastest known general method for factoring integers having more than 120 digits. In this thesis we will will study the algebraic number theory that lies behind the algorithm, describe ...
    • Offline Assisted Group Key Exchange 

      Boyd, Colin Alexander; Davies, Gareth Thomas; Gjøsteen, Kristian; Jiang, Yao (Journal article; Peer reviewed, 2018)
      We design a group key exchange protocol with forward secrecy where most of the participants remain offline until they wish to compute the key. This is well suited to a cloud storage environment where users are often offline, ...