Hi, I have also just encountered the incorrect sign for BooleanFunction walsh_hadamard_transform(). In addition, I would like to point out that the documentation at http://doc.sagemath.org/html/en/reference/cryptography/sage/crypto/boolean_function.html agrees with the usual definition and not with the current implementation, and the doctest on that page does not check for correct sign. Finally, the sign on the Walsh Hadamard transform affects the definition of the dual, self-dual bent functions, etc. In particular, the function $x_1 x_2$ is self dual under the usual definition http://www.inderscienceonline.com/doi/abs/10.1504/IJICoT.2010.032864 but not when when the current implementation is used. Clearly the current sign is a bug, rather than just a difference in convention. All the best, Paul
On Tuesday, 30 December 2014 18:18:47 UTC+11, William wrote: > > ---------- Forwarded message ---------- > From: Aneta Buraczyńska <an.bura...@gmail.com <javascript:>> > Date: Mon, Dec 29, 2014 at 11:03 PM > Subject: error in Sage > To: William Stein <wst...@gmail.com <javascript:>> > > > Dear Mr William Stein, > > I am writing with request for contact to Sage creators or reading my > problem. In module sage.crypto.boolean_function there is a function: > walsh_hadamard_transform(). I think this function gives wrong results. > For instance for function f defined by truth table (1, 0, 0, 0, 0, 1, > 1, 1) sage gives vector (0, 0, 0, 0, -4, 4, 4, 4) as a result, but the > correct value is (0, 0, 0, 0, 4, -4, -4, -4). All functions that I > verified have in sage error result due to incorrect signs. On appendix > I send a document with the calculations showing my statement. > > I will be grateful for help in this problem. > > Yours Sincerely, > > Aneta Buraczyńska > > > > > -- > William Stein > Professor of Mathematics > University of Washington > http://wstein.org > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
