New Stream Cipher Designs

Volume 4986 of the series Lecture Notes in Computer Science pp 140-151

Decim v2

  • Côme BerbainAffiliated withOrange Labs
  • , Olivier BilletAffiliated withOrange Labs
  • , Anne CanteautAffiliated withINRIA Rocquencourt
  • , Nicolas CourtoisAffiliated withUniversity College of London
  • , Blandine DebraizeAffiliated withGemaltoUniversité de Versailles
  • , Henri GilbertAffiliated withOrange Labs
  • , Louis GoubinAffiliated withGemaltoUniversité de Versailles
  • , Aline GougetAffiliated withGemalto
  • , Louis GranboulanAffiliated withEADS
    • , Cédric LauradouxAffiliated withINRIA Rocquencourt
    • , Marine MinierAffiliated withINSA Lyon
    • , Thomas PorninAffiliated withCryptolog International
    • , Hervé SibertAffiliated withNXP Semiconductors

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In this paper, we present Decim v2, a stream cipher hardware-oriented selected for the Phase 3 of the ECRYPT stream cipher project eSTREAM. As required by the initial call for hardware-oriented stream cipher contribution, Decim v2 manages 80-bit secret keys and 64-bit public initialization vectors. The design of Decim v2 combines two filtering mechanisms: a nonlinear Boolean filter over a LFSR, followed by an irregular decimation mechanism called the ABSG. Since designers have been invited to demonstrate flexibility of their design by proposing variants that take 128-bit keys, we also present a 128-bit security version of Decim called Decim-128.