A Lattice-Based Public-Key Cryptosystem

In 1998, Cai and Cusick proposed a lattice-based public-key cryptosystem based on the similar ideas of the Ajtai-Dwork cryptosystem, but with much less data expansion. However, they didn't give any security proof. In our paper, we present an efficient ciphertext-only attack which runs in polynomial time against the cryptosystem to recover the message, so the Cai-Cusick lattice-based public-key cryptosystem is not secure. We also present two chosen-ciphertext attacks to get a similar private key which acts as the real private key.

• Type: Conference
• Year: 1998
• Where: SACRYPT
• Authors: Jin-yi Cai, Thomas W. Cusick
• Keywords: Ajtai-Dwork Cryptosystem, Cryptology, Lattice-based Public-key Cryptosystem, Private Key, SACRYPT 1998