NTRU-like FHE schemes

To obtain a practical and applicable FHE scheme, one of the crucialsteps is taken by showing the construction of an FHE scheme from NTRU Encrypt, which is an old encryption scheme proposed by Hoffstein, Pipher, and Silvermanin in [Hoffstein et al. 1998]. Specifically, how to obtain a multi-key FHE from the NTRUEncrypt (called NTRU) was shown by [López-Alt et al. 2012]. NTRU encryption scheme is one of earliest attempts based on lattice problems. Compared with RSA and GGH cryptosystems, NTRU improves the efficiency significantly in both hardware and software implementations.