Most practical applications use hybrid encryption to deal with large plaintext messages since the efficiency of the public key encryption algorithm is low. As a main part of hybrid encryption schemes, Key Encapsulation Mechanism (KEM) allows a sender to generate a random session key and distribute it to recipient. In some communication scenario, one-to-group model is of importance. In this pape...

Previous de nitions of designated con rmer signatures in the literature are incomplete, and the proposed security de nitions fail to capture key security properties, such as unforgeability against malicious con rmers and non-transferability. We propose new de nitions. Previous schemes rely on the random oracle model or set-up assumptions, or are secure with respect to relaxed security de nition...

Designated verifier signature schemes allow a signer to convince only the designated verifier that a signed message is authentic. We define attack models on the unforgeability property of such schemes and analyze relationships among the models. We show that the no-message model, where an adversary is given only public keys, is equivalent to the model, where an adversary has also oracle access t...

The University of British Columbia Hospital program was designed to augment existing provincial capacity for hip and knee replacement. The patient-surgeon relationship was maintained throughout the entire care pathway and "ring-fenced" capacity (i.e., designated hospital ward bed and operating room capacity that is geographically remote from the emergency intake of patients) minimized the risk ...

It has been a long-standing challenge to produce air-stable few- or monolayer samples of phosphorene because thin phosphorene films degrade rapidly in ambient conditions. Here we demonstrate a new highly controllable method for fabricating high quality, air-stable phosphorene films with a designated number of layers ranging from a few down to monolayer. Our approach involves the use of oxygen p...

In a proxy signature scheme, a user delegates his/her signing capability to another user in such a way that the latter can sign messages on behalf of the former. In this paper, we first propose a provably secure proxy signature scheme, which is based on a two-party Schnorr signature scheme. Then, we extend this basic scheme into designated-verifier proxy signatures (DVPS). More specifically, we...

Multi-Designated Verifier Signatures (MDVS) are privacy-oriented signatures that can only be verified by a set of users specified by the signer. We propose two new generic constructions of MDVS from variants of existing cryptographic schemes, which are ring signature from anonymous subset and multi-chameleon hash. We first devise a single add-on protocol which enables many existing identity-bas...

We give a generic construction for universal designated-verifier signature schemes from a large class, C, of signature schemes. The resulting schemes are efficient and have two important properties. Firstly, they are provably DV-unforgeable, non-transferable and also non-delegatable. Secondly, the signer and the designated verifier can independently choose their cryptographic settings. We also ...