• Cloud-assisted Asynchronous Key Transport with Post-Quantum Security 

      Davies, Gareth Thomas; Galteland, Herman; Gjøsteen, Kristian; Jiang, Yao (Peer reviewed; Journal article, 2020)
      In cloud-based outsourced storage systems, many users wish to securely store their files for later retrieval, and additionally to share them with other users. These retrieving users may not be online at the point of the ...
    • Definitions for Plaintext-Existence Hiding in Cloud Storage 

      Boyd, Colin Alexander; Davies, Gareth Thomas; Gjøsteen, Kristian; Raddum, Håvard; Toorani, Mohsen (ARES 2018;Article No. 41, Chapter, 2018)
      Cloud storage services use deduplication for saving bandwidth and storage. An adversary can exploit side-channel information in several attack scenarios when deduplication takes place at the client side, leaking information ...
    • Exploring Libraries for Homomorphic Encryption 

      Lokanath, Ashmitha (Master thesis, 2018)
      Fully homomorphic encryption (FHE) is a very modern encryption technique which allows any number of efficient computations to be carried out on the encrypted data without having access to the secret key. FHE schemes can ...
    • Fast and Secure Updatable Encryption 

      Boyd, Colin Alexander; Davies, Gareth Thomas; Gjøsteen, Kristian; Jiang, Yao (Peer reviewed; Journal article, 2020)
      Updatable encryption allows a client to outsource ciphertexts to some untrusted server and periodically rotate the encryption key. The server can update ciphertexts from an old key to a new key with the help of an update ...
    • Oblivious RAM in practice 

      Thoresen, Olav Sortland (Master thesis, 2019)
      Målet med denne masteroppgaven er å studere ytelsen til nåværende Oblivious RAM (ORAM) løsninger og undersøke hvor praktiske de er i et skylagrings-scenario. For å gjøre dette ble tre ORAM løsninger (ObliviStore, CURIOUS ...
    • 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, ...
    • Secure data sharing in the cloud 

      Gran, Eivind Nordal (Master thesis, 2019)
      Sikkerhet innen skydeling er et viktig tema i verden i dag. Sikker- hetssystemet i de vanligste løsningene for skydeling krever at brukeren stoler på leverandøren av skytjenesten for å beskytte den opplastede dataen. En ...
    • Security notions for cloud storage and deduplication 

      Boyd, Colin Alexander; Davies, Gareth Thomas; Gjøsteen, Kristian; Raddum, Håvard; Toorani, Mohsen (Journal article; Peer reviewed, 2018)
      Cloud storage is in widespread use by individuals and enterprises but introduces a wide array of attack vectors. A basic step for users is to encrypt their data, yet it is not obvious what security properties are required ...
    • Side channels in deduplication: trade-offs between leakage and efficiency 

      Armknecht, Frederik; Boyd, Colin Alexander; Davies, Gareth Thomas; Gjøsteen, Kristian; Toorani, Mohsen (Chapter, 2017)
      Deduplication removes redundant copies of files or data blocks stored on the cloud. Clientside deduplication, where the client only uploads the file upon the request of the server, provides major storage and bandwidth ...