Policy-Controlled Signature from NTRU Lattice

Abstract

Policy-controlled signature (PCS) was introduced by Pairat Thorncharoensri et al. at ICICS 2009, and improved at Computer Standards & Interfaces 2017. In this type of digital signature, signer can sign a message with some policies. Any verifier who does not satisfies the policies cannot verify the message. They also extended the notion of policy-controlled signature, and called it "universal policy-controlled signature". In their extended notion, they improve the flexibility of the PCS scheme by allowing a third party to equip the signature with policy, rather than the signer. In this work, we use the recent techniques in lattice to construct policy- controlled based signature from NTRU lattice. In particular, we adapt Léo Ducas et al.'s encryption and signature protocol on lattice (ASIACRYPT 2014), and combine them with Pairat Thorncharoensri et al.'s work to satisfy the properties of policy-controlled signature. Our contribution is developing the first quantum- resistant schema based on the policy-controlled signature.