Paper 2020/455
Cryptanalysis of LEDAcrypt
Daniel Apon, Ray Perlner, Angela Robinson, and Paolo Santini
Abstract
We report on the concrete cryptanalysis of LEDAcrypt, a 2nd Round candidate in NIST's Post-Quantum Cryptography standardization process and one of 17 encryption schemes that remain as candidates for near-term standardization. LEDAcrypt consists of a public-key encryption scheme built from the McEliece paradigm and a key-encapsulation mechanism (KEM) built from the Niederreiter paradigm, both using a quasi-cyclic low-density parity-check (QC-LDPC) code. In this work, we identify a large class of extremely weak keys and provide an algorithm to recover them. For example, we demonstrate how to recover 1 in $2^{47.72}$ of LEDAcrypt's keys using only $2^{18.72}$ guesses at the 256-bit security level. This is a major, practical break of LEDAcrypt. Further, we demonstrate a continuum of progressively less weak keys (from extremely weak keys up to all keys) that can be recovered in substantially less work than previously known. This demonstrates that the imperfection of LEDAcrypt is fundamental to the system's design.
Note: Fixed a few typos
Metadata
- Available format(s)
-
PDF
- Category
- Public-key cryptography
- Publication info
- Preprint. MINOR revision.
- Keywords
- NIST PQCLEDAcryptMcElieceQC-LDPCCryptanalysis
- Contact author(s)
-
daniel apon @ nist gov
ray perlner @ nist gov
angela robinson @ nist gov
p santini @ pm univpm it - History
- 2020-04-20: last of 2 revisions
- 2020-04-20: received
- See all versions
- Short URL
- https://ia.cr/2020/455
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2020/455,
author = {Daniel Apon and Ray Perlner and Angela Robinson and Paolo Santini},
title = {Cryptanalysis of {LEDAcrypt}},
howpublished = {Cryptology {ePrint} Archive, Paper 2020/455},
year = {2020},
url = {https://eprint.iacr.org/2020/455}
}
