Paper 2017/667

High-speed key encapsulation from NTRU

Andreas Hülsing, Joost Rijneveld, John M. Schanck, and Peter Schwabe


This paper presents software demonstrating that the 20-year-old NTRU cryptosystem is competitive with more recent lattice-based cryptosystems in terms of speed, key size, and ciphertext size. We present a slightly simplified version of textbook NTRU, select parameters for this encryption scheme that target the 128-bit post-quantum security level, construct a KEM that is CCA2-secure in the quantum random oracle model, and present highly optimized software targeting Intel CPUs with the AVX2 vector instruction set. This software takes only 307914 cycles for the generation of a keypair, 48646 for encapsulation, and 67338 for decapsulation. It is, to the best of our knowledge, the first NTRU software with full protection against timing attacks.

Available format(s)
Publication info
A major revision of an IACR publication in CHES 2017
Post-quantum cryptolattice-based cryptoNTRUCCA2-secure KEMQROMAVX2
Contact author(s)
authors-ntrukem @ joostrijneveld nl
2017-08-29: last of 2 revisions
2017-07-05: received
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      author = {Andreas Hülsing and Joost Rijneveld and John M.  Schanck and Peter Schwabe},
      title = {High-speed key encapsulation from NTRU},
      howpublished = {Cryptology ePrint Archive, Paper 2017/667},
      year = {2017},
      note = {\url{}},
      url = {}
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