Paper 2020/056

AKCN-E8: Compact and Flexible KEM from Ideal Lattice

Zhengzhong JIn and Yunlei Zhao


A remarkable breakthrough in mathematics in recent years is the proof of the long-standing conjecture: sphere packing (i.e., packing unit balls) in the $E_8$ lattice is optimal in the sense of the best density \cite{V17} for sphere packing in $\mathbb{R}^8$. In this work, based on the $E_8$ lattice code, we design a mechanism for asymmetric key consensus from noise (AKCN), referred to as AKCN-E8, for error correction and key consensus. As a direct application of the AKCN-E8 code, we present highly practical key encapsulation mechanism (KEM) from the ideal lattice based on the ring learning with errors (RLWE) problem. Compared to the RLWE-based NewHope-KEM \cite{newhope-NIST}, which is a variant of NewHope-Usenix \cite{newhope15} and is now a promising candidate in the second round of NIST post-quantum cryptography (PQC) standardization competition, our AKCN-E8-KEM has the following advantages: * The size of shared-key is doubled.. * More compact ciphertexts, at the same or even higher security level. * More flexible parameter selection for tradeoffs among security, ciphertext size and error probability.

Available format(s)
Cryptographic protocols
Publication info
Preprint. MINOR revision.
post-quantum cryptographylatticeKEM
Contact author(s)
ylzhao @ fudan edu cn
2020-01-22: last of 2 revisions
2020-01-21: received
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      author = {Zhengzhong JIn and Yunlei Zhao},
      title = {{AKCN}-E8: Compact and Flexible {KEM}  from Ideal Lattice},
      howpublished = {Cryptology ePrint Archive, Paper 2020/056},
      year = {2020},
      note = {\url{}},
      url = {}
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