Paper 2019/040
NTTRU: Truly Fast NTRU Using NTT
Vadim Lyubashevsky and Gregor Seiler
Abstract
We present NTTRU -- an IND-CCA2 secure NTRU-based key encapsulation scheme that uses the number theoretic transform (NTT) over the cyclotomic ring $Z_{7681}[X]/(X^{768}-X^{384}+1)$ and produces public keys and ciphertexts of approximately $1.25$ KB at the $128$-bit security level. The number of cycles on a Skylake CPU of our constant-time AVX2 implementation of the scheme for key generation, encapsulation and decapsulation is approximately $6.4$K, $6.1$K, and $7.9$K, which is more than 30X, 5X, and 8X faster than these respective procedures in the NTRU schemes that were submitted to the NIST post-quantum standardization process. These running times are also, by a large margin, smaller than those for all the other schemes in the NIST process. We also give a simple transformation that allows one to provably deal with small decryption errors in OW-CPA encryption schemes (such as NTRU) when using them to construct an IND-CCA2 key encapsulation.
Metadata
- Available format(s)
- Category
- Public-key cryptography
- Publication info
- Published by the IACR in TCHES 2019
- Keywords
- NTRULattice CryptographyAVX2NTT
- Contact author(s)
- vadim lyubash @ gmail com,gseiler @ inf ethz ch
- History
- 2020-02-09: last of 4 revisions
- 2019-01-17: received
- See all versions
- Short URL
- https://ia.cr/2019/040
- License
-
CC BY