Paper 2021/440

Two modifications for Loidreau's code-based cryptosystem

Wenshuo Guo and Fangwei Fu


This paper presents two modifications for Loidreau’s code-based cryptosystem. Loidreau’s cryptosystem is a rank metric code-based cryptosystem constructed by using Gabidulin codes in the McEliece setting. Recently a polynomial-time key recovery attack was proposed to break Loidreau’s cryptosystem in some cases. To prevent this attack, we propose the use of subcodes to disguise the secret codes in Modification I. In Modification II, we choose a random matrix of low column rank over F q to mix with the secret matrix. According to our analysis, these two modifications can both resist the existing structural attacks. Additionally, we adopt the systematic generator matrix of the public code to make a reduction in the public-key size.

Available format(s)
Public-key cryptography
Publication info
Published elsewhere. Minor revision.
public-key cryptography
Contact author(s)
ws_guo @ mail nankai edu cn
2021-04-17: last of 2 revisions
2021-04-06: received
See all versions
Short URL
Creative Commons Attribution


      author = {Wenshuo Guo and Fangwei Fu},
      title = {Two modifications for Loidreau's code-based cryptosystem},
      howpublished = {Cryptology ePrint Archive, Paper 2021/440},
      year = {2021},
      note = {\url{}},
      url = {}
Note: In order to protect the privacy of readers, does not use cookies or embedded third party content.