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In cryptography, MESH is a block cipher designed in 2002 by Jorge Nakahara, Jr., Vincent Rijmen, Bart Preneel, and Joos Vandewalle. MESH is based directly on IDEA and uses the same basic operations.

Designers Nakahara, Rijmen, Preneel, Vandewalle
First published 2002
Derived from IDEA
Cipher detail
Key sizes 128, 192, or 256 bits
Block sizes 64, 96, or 128 bits
Structure Lai-Massey scheme
Rounds 8.5, 10.5, or 12.5
Best public cryptanalysis
2 rounds can be broken using 128, 161, or 225 known plaintexts

MESH is actually a family of 3 variant ciphers with block sizes of 64, 96, and 128 bits. [1]The key size is twice the block size. The number of rounds is 8.5, 10.5, or 12.5, depending on the block size. The algorithm uses a Lai-Massey scheme based on IDEA's, but with a larger round structure, or "MA-box". MESH also has a more complex key schedule than IDEA, intended to prevent weak keys and other insecure patterns in subkeys.


  • J. Nakahara, Jr; V. Rijmen; B. Preneel; J. Vandewalle (2002). "The MESH Block Ciphers" (PDF/PostScript). Retrieved 8 February 2007.
  • J. Nakahara Jr.; B. Preneel & J. Vandewalle (2003). "The Biryukov-Demirci Attack on IDEA and MESH Ciphers" (PDF/PostScript). Retrieved 4 October 2007.
  1. ^ The MESH Block Ciphers. Austria. p. 2.