I am reposting a comment I just added to the topic, "Fwd: error in Sage" in the hopes that it will be more likely to be seen this way.
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 -- 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.
