Format preserving encryption has three modes FE1( FFX) , FE2(VAES) , FE3(BPS) . All of them are based on Feistel Networks .Can somebody explain how they differ from each other ?

  • $\begingroup$ It's even worse, FFX contains several different modes plus a bunch of parameters. $\endgroup$ – CodesInChaos Nov 8 '13 at 13:26

Ff1,2,3 are basically inspired by LubyRack off constructions . At the core they differ in their round functions and key scheduling

FF1 supports greater range of lengths and a tweak

FF2 generates subkey for each iteration to thwart any side channel attacks

FF3 has tweaks is split and used in rounding function, also the reverse the sub-strings of given input string while using in round function,

Both FF1,FF2 has 10 rounds FF3 has only 8 rounds

Read more at NIST's 800 38 G draft

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  • $\begingroup$ How do you decide which mode to use? $\endgroup$ – erotavlas Apr 30 '15 at 20:07
  • $\begingroup$ depends you need to pick on your requirements. you need greater range of lengths of formats or performance etc. $\endgroup$ – sashank May 1 '15 at 16:38
  • $\begingroup$ It would be nice to know also the patent constraint on using these. HP holds patent for FF1 sub-components. I guess the use in commercial software is somehow limited. I don't know how - contacting HP to learn more. Will let you know. $\endgroup$ – Dusan Klinec Jul 31 '16 at 8:31
  • $\begingroup$ if you want a non-patented solution , check this github.com/cisco/libfnr , not a standard though , Disclaimer: am the co-author of this scheme $\endgroup$ – sashank Aug 1 '16 at 4:07

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