Volume 10 - Issue 4
Identity-based Unidirectional Proxy Re-Encryption and Re-Signature in Standard Model: Lattice-based Constructions
- Priyanka Dutta
Institute of Cybersecurity and Cryptology School of Computing and Information Technology University of Wollongong Northfields Avenue, Wollongong NSW 2522, Australia
pdutta@uow.edu.au
- Willy Susilo
Institute of Cybersecurity and Cryptology School of Computing and Information Technology University of Wollongong Northfields Avenue, Wollongong NSW 2522, Australia
wsusilo@uow.edu.au
- Dung Hoang Duong
Institute of Cybersecurity and Cryptology School of Computing and Information Technology University of Wollongong Northfields Avenue, Wollongong NSW 2522, Australia
hduong@uow.edu.au
- Joonsang Baek
Institute of Cybersecurity and Cryptology School of Computing and Information Technology University of Wollongong Northfields Avenue, Wollongong NSW 2522, Australia
baek@uow.edu.au
- Partha Sarathi Roy
Institute of Cybersecurity and Cryptology School of Computing and Information Technology University of Wollongong Northfields Avenue, Wollongong NSW 2522, Australia
partha@uow.edu.au
Keywords: Learning with error, Small integer solution, Proxy Re-Encryption, Proxy Re-Signature
Abstract
Proxy re-encryption (PRE) securely enables the re-encryption of ciphertexts from one key to another,
without relying on trusted parties, i.e., it offers delegation of decryption rights. PRE allows a
semi-trusted third party termed as a “proxy” to securely divert encrypted files of a user (delegator)
to another user (delegatee) without revealing any information about the underlying files to the proxy.
Whereas, Proxy re-signature (PRS) allows a semi-trusted proxy to convert a signature of a user (delegatee)
into a signature of another user (delegator) on the same message, but the proxy cannot produce
new valid signature on new messages for either delegator or delegatee. To eliminate the necessity
of having a costly certificate verification process, Green and Ateniese [18] introduced an identitybased
PRE (IB-PRE) and Shao et al. [32] introduced an identity-based PRS (IB-PRS). The potential
applicability of IB-PRE and IB-PRS leads to intensive research from its first instantiations. Unfortunately,
till today, there is no unidirectional IB-PRE and IB-PRS secure in the standard model, which
can withstand quantum attack. In this paper, we provide, for the first time, concrete constructions
of unidirectional IB-PRE and IB-PRS which are secure in standard model based on the hardness of
learning with error problem and small integer solution problem, respectively. Our technique is to
use the novel trapdoor delegation technique of Micciancio and Peikert. The way we use trapdoor
delegation technique may prove useful for functionalities other than PRE and PRS as well.