Score:1

FF1 vs FF3 FPE Encryption

br flag

FF1 and FF3 both are Feistel-based FPE schemes with r=10 rounds and 8 rounds respectively. The other difference I got to know is that the FF1 considers the right half of the message bigger while FF3 considers the left half input to Feistel network bigger. Is there any other difference in the construction of FF1 and FF3?

fgrieu avatar
ng flag
I guess the question should be about FF1 and FF3-1, as defined in [draft SP 800-38G Rev. 1](https://doi.org/10.6028/NIST.SP.800-38Gr1-draft). An other useful reference will be [draft 1.1 of The FFX Mode of Operation for Format-Preserving Encryption](https://csrc.nist.gov/csrc/media/projects/block-cipher-techniques/documents/bcm/proposed-modes/ffx/ffx-spec.pdf).
Ben Mares avatar
mx flag
The original reference for FF3 (before FF3-1) is [BPS: a Format-Preserving Encryption Proposal](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.694.918&rep=rep1&type=pdf). I find it much more readable than the NIST document. (Unfortunately I can't answer your question myself since I haven't read these papers thoroughly enough.)
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