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Grand Cru (cipher)

Grand Cru
Designers Johan Borst
First published 2000
Derived from Rijndael
Cipher detail
Key sizes 128 bits
Block sizes 128 bits
Structure Substitution-permutation network
Rounds 10

In cryptography, Grand Cru is a block cipher invented in 2000 by Johan Borst. It was submitted to the NESSIE project, but was not selected.

Grand Cru is a 10-round substitution-permutation network based largely on Rijndael (or AES).[1] It replaces a number of Rijndael's unkeyed operations with key-dependent ones, in a way consistent with the security purposes of each operation. The intent is to produce a cipher at least as secure as Rijndael, and perhaps much more secure. The block size and key size are both 128 bits, and the key schedule is the same as Rijndael's.

Grand Cru is designed on the principle of multiple layered security.[2][3] It is equivalent to a chain of 4 subciphers with independent keys, such that if 3 of the keys are known, the remaining cipher should still be secure.


  1. ^ Murphy, Sean; White, Juliette (2001-09-23). "Security Evaluation of NESSIE First Phase: 2.4.9 Grand Cru" (PDF). p. 26. Retrieved 2018-09-13.
  2. ^ Khan, Azhar Ali; Murtaza, Ghulam (2011-07-15). "Efficient Implementation of Grand Cru with TI C6x+ Processor". Retrieved 2018-09-13.
  3. ^ Ghulam Murtaza, Azhar Ali Khan, Syed Wasi Alam, Aqeel Farooqi (2011-04-09). "Fortification of AES with Dynamic Mix-Column Transformation". Retrieved 2018-09-13.