Gleeok: A Family of Low-Latency PRFs and its Applications to Authenticated Encryption


  • Ravi Anand University of Hyogo, Kobe, Japan
  • Subhadeep Banik University of Lugano, Lugano, Switzerland
  • Andrea Caforio EPFL, Lausanne, Switzerland
  • Tatsuya Ishikawa University of Hyogo, Kobe, Japan
  • Takanori Isobe University of Hyogo, Kobe, Japan
  • Fukang Liu Tokyo Institute of Technology, Tokyo, Japan
  • Kazuhiko Minematsu NEC, Kawasaki, Japan; Yokohama National University, Yokohama, Japan
  • Mostafizar Rahman University of Hyogo, Kobe, Japan
  • Kosei Sakamoto Mitsubishi Electric Corporation, Kamakura, Japan



Ultra-low latency, Pseudorandom function, Authenticated encryption, Short input, Memory encryption, Beyond 5G (B5G)


In this paper, we propose a new family of low-latency pseudorandom functions (PRFs), dubbed Gleeok.
Gleeok utilizes three 128-bit branches to achieve a 256-bit key size while maintaining low latency. The first two branches are specifically designed to defend against statistical attacks, especially for differential attacks, while the third branch provides resilience against algebraic attacks. This unique design enables Gleeok to offer ultralow latency while supporting 256-bit keys, setting it apart from existing ciphers dedicated to low-latency requirements. In addition, we propose wide-block variants having three 256-bit branches. We also present an application of Gleeok to short-input authenticated encryption which is crucial for memory encryption and various realtime communication applications. Furthermore, we present comprehensive hardware implementation results that establish the capabilities of Gleeok and demonstrate its competitiveness against related schemes in the literature. In particular, Gleeok achieves a minimum latency of roughly 360 ps with the NanGate 15 nm cell library and is thus on par with related low-latency schemes that only feature 128-bit keys while maintaining minimal overhead when equipped in an authenticated mode of operation.




How to Cite

Anand, R., Banik, S., Caforio, A., Ishikawa, T., Isobe, T., Liu, F., … Sakamoto, K. (2024). Gleeok: A Family of Low-Latency PRFs and its Applications to Authenticated Encryption. IACR Transactions on Cryptographic Hardware and Embedded Systems, 2024(2), 545–587.