Hi vpv, you can certainly post-process the first option to get an equation system in the plaintext and key variables alone. You'll need an appropriate term ordering where each layer's head term is bigger than the previous layer's head term. You'll also replace the S-Box equations by direct equations which is just the Gröbner basis with this variable order + 'lex'. Finally, you compute the normal form of each layer w.r.t. the last layer.
As for the direct generation: * I'd be very happy if you'd share your code! I would like to make sure that it fits into the current framework/is compatible and reuses the existing machinery. Are you doing that? * I'd guess it should be fairly straight forward (for someone knowing the code of mq.SR) to add what you want: (a) make some type checks more relaxed & user-friendly and (b) add support for 'variable encryption' by replacing sr.sub_bytes with a function returning equations. * In the upcoming version of Sage (3.1.2) mq.SR generates equation systems in PolyBoRi if asked to. * If we're going to support direct representation of ciphertext bits in plaintext and key variables we should also support GF(2^n) as base field not only GF(2), i.e. BES style equations. This will be slightly more involving. Cheers, Martin -- name: Martin Albrecht _pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99 _www: http://www.informatik.uni-bremen.de/~malb _jab: [EMAIL PROTECTED] --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
