A symmetric LWE-based Multi-Recipient Cryptosystem

TL;DR

This paper introduces a post-quantum symmetric cryptosystem based on LWE that allows a sender to encrypt multiple messages for different recipients in a single broadcast, ensuring security and privacy.

Contribution

It presents a novel multi-recipient symmetric encryption scheme based on LWE, suitable for noisy data like images, with security proofs and practical application example.

Findings

Secure multi-recipient encryption scheme based on LWE

Encryption of multiple images demonstrated

Recipient privacy maintained in broadcast setting

Abstract

This article describes a post-quantum multirecipient symmetric cryptosystem whose security is based on the hardness of the LWE problem. In this scheme a single sender encrypts multiple messages for multiple recipients generating a single ciphertext which is broadcast to the recipients. Each recipient decrypts the ciphertext with her secret key to recover the message intended for her. In this process, the recipient cannot efficiently extract any information about the other messages. This scheme is intended for messages like images and sound that can tolerate a small amount of noise. This article introduces the scheme and establishes its security based on the LWE problem. Further, an example is given to demonstrate the application of this scheme for encrypting multiple images.