I enjoy a wide interest in various topics related to cryptography and coding theory, mainly related to concrete applications. Current research topics include privacy preserving techniques (MPC/FHE, ZK-SNARKs/STARKs, DeFi, Blockchains), algorithms and computation, post-quantum security...

Academic article

• Navid Ghaedi Bardeh; Sondre Rønjom (2019). Practical attacks on reduced-round AES. (external link)
• Sondre Rønjom; Guang Gong; Tor Helleseth (2007). A survey of recent attacks on the filter generator. (external link)
• Sondre Rønjom; Tor Helleseth (2007). A new attack on the filter generator. (external link)
• Sondre Rønjom; Tor Helleseth (2007). Attacking the filter generator over GF(2^m). (external link)
• Navid Ghaedi Bardeh; Sondre Rønjom (2019). The Exchange Attack: How to Distinguish Six Rounds of AES with 2^88.2 Chosen Plaintexts. (external link)
• Sondre Rønsom; Håvard Raddum (2008). On the Number of Linearly Independent Equations Generated by XL. (external link)
• Guang Gong; Sondre Rønjom; Tor Helleseth et al. (2011). Fast discrete Fourier spectra attacks on stream ciphers. (external link)
• Sondre Rønjom; Tor Helleseth (2007). The linear vector space spanned by the nonlinear filter generator. (external link)
• Sondre Rønjom; Navid Ghaedi Bardeh; Tor Helleseth (2017). Yoyo tricks with AES. (external link)
• Sondre Rønjom; Guang Gong; Tor Helleseth (2007). On attacks on filtering generators using linear subspace structures. (external link)
• Christof Beierle; Patrick Felke; Gregor Leander et al. (2022). Decomposing Linear Layers. (external link)
• Lorenzo Grassi; Dmitry Khovratovich; Sondre Rønjom et al. (2022). The Legendre Symbol and the Modulo-2 Operator in Symmetric Schemes over Fⁿ <inf>p</inf>: Preimage Attack on Full Grendel. (external link)
• Simen Gaure; Stefanos Koffas; Stjepan Picek et al. (2025). L 2 · M = C2 LARGE LANGUAGE MODELS ARE COVERT CHANNELS. (external link)
• Sondre Rønjom (2017). Improving algebraic attacks on stream ciphers based on linear feedback shift register over \mathbb {F}_{2^k}. (external link)
• Lorenzo Grassi; Christian Rechberger; Sondre Rønjom (2017). A new structural-differential property of 5-round AES. (external link)

Conference lecture

• Sondre Rønjom; Carlos Cid (2010). Nonlinear Equivalence of Stream Ciphers. (external link)
• Sondre Rønjom; Gregor Leander; Brice Minaud (2015). A Generic Approach to Invariant Subspace Attacks: Cryptanalysis of Robin, iSCREAM and Zorro. (external link)

Doctoral thesis (PhD)

• Sondre Rønjom (2009). Cryptanalysis of ciphers over finite cyclic groups. (external link)

Professional article

• Anders Andersen; Tor Berre; Pål Ellingsen et al. (2019). Informasjonssikkerhet i høyere utdanning. (external link)

Lecture

• Anders Andersen; Tor Berre; Pål Ellingsen et al. (2019). Informasjonssikkerhet i høyere utdanning. (external link)

Academic book chapter

• Tor Helleseth; Michal Hojsik; Sondre Rønjom (2009). Algebraic Attacks on Filter and Combiner Generator. (external link)
• Tor Helleseth; Sondre Rønjom (2011). Simplifying algebraic attacks with univariate analysis. (external link)

See a complete overview of publications in Cristin.