-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I have not been much for posting on the list until now (nothing much other than opinions to add, and there seem to be plenty of those to go around already), but Mr. Fairbrother's post demanded a response. Peter Fairbrother wrote:

I am developing a form of deniable encryption (as part of m-o-o-t) that works slightly differently and does not involve message-size increases - in fact it it decreases message size. ... The main implementation problems I have are coding time and that the only parser that works well enough is proprietary. If anyone else is working on something similar I would like to know. I'm probably not a cypherpunk, more a privacy avocate, but I do write code. ...

I am working on what I intend to be an industrial-strength, open-source grammar-based generation toolkit, which might fit the bill for the kind of thing he posted about (using grammars for privacy applications). I'm only concerned with generation right now and not parsing, but going in the other direction is on my list of desired features. Unfortunately, I have a real day job and am trying to get *something* good enough done in time to submit to CodeCon (which deadline is coming up soon, I think). The goals of the toolkit are to be highly reusable/usable in many contexts, high performance, and extremely flexible. I would be interested in knowing what kinds of features you envision being useful from a toolkit such as this for your purposes. The toolkit I'm building is in the form of a plain old library written in ANSI C, with as few environmental dependencies as possible. There are two main data structures: grammars (gram_t *), and grammar generators (gram_gen_t *). Grammars can be constructed by API calls or by handing a file or string containing eBNF to a function that knows how to turn eBNF into a gram_t. Grammar generators are built from grammars, and can have different generation strategies associated with them (random, breadth first, depth first). Generation itself happens by means of callbacks associated with terminals in the underlying grammar, so the grammar can really be about anything, not just text (e.g. you could write callbacks to generate musical tones, raw network traffic, geometric shapes ala shape grammars (http://www.shapegrammar.org/) etc.). I'm much fuzzier on how I would like the eventual parsing side of the house to work, but I'm experienced enough in this subject generally to build what I need when I finally figure out how I want it to work exactly. In an ideal world, you hand a gram_t to a third API that creates an acceptor for the grammar that is similarly insulated from how the actual raw tokens are presented (same kind of callback-driven fu I do for generators in the lexical analysis side of the house), but I was also thinking it would be really cool to do some sort of code generator instead (or use antlr or byacc or something). One principle that I intend to follow is to make it easy to use this toolkit to build up libraries of primitives that can be joined together, so that common uses can be accomodated with as little code on the part of the user as possible. For instance, although there is nothing specific in the core with regard to generating text (like e-mail), this is an obvious common usage (if only for debugging), so there will be primitives in the library that make it easy to "wire up" your grammar and get it to spit out text (I was thinking of some XML-based config language that you could use to associate dynamically-loaded primitives from some .so or .dll by name with terminals, etc.). If any of this jibes with the kind of things you're thinking about, I'd appreciate hearing from you; although I have a head full of ideas on what I'd like to do with it, it's always helpful to hear from people with other perspectives who are thinking about similar things. I find myself often working in a vacuum, late at night, with nothing to go on but my own feeling of what is useful. Perhaps it's time to delurk. In any event, if anyone besides Mr. Fairbrother has any ideas, opinions or encouragement, it would be most welcome (and yes, I am aware of Disappearing Cryptography - it was, along with shape grammars, the source of much of my inspiration). Pax, --A - -- attila % member, st.Alphonsos collective % unix,tcp/ip,security,hard bits attila@stalphonsos.com % gpg key http://stalphonsos.com/~attila/gpgkey.txt -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (OpenBSD) Comment: For info see http://www.gnupg.org iD8DBQE93TMCr88iLU/8u5wRArHRAJ9/thKhVhBUNdSRkopkDMYC0T3Z5gCgg2Dt AzHMmk+zVzJeE72cGa1Eyl8= =4TEf -----END PGP SIGNATURE-----