Paper 2014/421

FNR : Arbitrary length small domain block cipher proposal

Sashank Dara and Scott Fluhrer


We propose a practical flexible (or arbitrary) length small domain block cipher, FNR encryption scheme. FNR denotes Flexible Naor and Reingold. It can cipher small domain data formats like IPv4, Port numbers, MAC Addresses, Credit card numbers, any random short strings while preserving their input length. In addition to the classic Feistel networks, Naor and Reingold propose usage of Pair-wise independent permutation (PwIP) functions based on Galois Field GF(2n). Instead we propose usage of random NXN Invertible matrices in GF(2).

Note: Camera Print version of the paper sent to conference

Available format(s)
Secret-key cryptography
Publication info
Published elsewhere. MINOR revision.Fourth International Conference on Security, Privacy, and Applied Cryptography Engineering (SPACE 2014) Defence Institute of Advanced Technology, Pune, India, 18th - 22nd October 2014
block ciphers
Contact author(s)
sadara @ cisco com
2014-07-26: last of 5 revisions
2014-06-06: received
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Creative Commons Attribution


      author = {Sashank Dara and Scott Fluhrer},
      title = {FNR : Arbitrary length small domain block cipher proposal},
      howpublished = {Cryptology ePrint Archive, Paper 2014/421},
      year = {2014},
      note = {\url{}},
      url = {}
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