At PKC 2003 Paeng, Jung, and Ha proposed a lattice based public key cryptosystem(PJH). It is originated from GGH, and designed as a hybrid of GGH and NTRUEncrypt in order to reduce the key size. They claimed that PJH is secure against all possible attacks, especially against lattice attacks. However, in this paper, we present a key recovery attack, based on lattice theory, against PJH. The runn...
