I've been following this thread and like the idea. I may be naïve or completely wrong, but all this sounds quite easy to solve in a design document and with pure javascript, although probably not very performant. Just take jens' structure proposal and modify openpgp.js a little bit, put the stuff into a validate_doc_update function, add the allowed public keys to a design doc (easy with a couchapp), et voilà: you get a completely replicable and transparent signature checker ;-)
If I find the time tomorrow, I'll take a shot on a proof of concept. The building blocks are there already... Cheers, Bernhard Am Mittwoch, 4. Juli 2012 schrieb Albin Stigö : > Sounds interesting.. I think I will take this to the developers mailing > list and see if I will be able to generate some interest in the idea.. > > Albin > > onsdag den 4. juli 2012 skrev Jan Bot : > > > Hi, > > > > This would really be a great feature: I'm using CouchDB to manage grid > > compute jobs and having the ability to sign a document using a private > key > > and check it server side with the public key could really make couchdb > part > > of the grid infrastructure. > > > > Cheers, > > > > Jan > > > > On Wed, Jul 4, 2012 at 11:17 AM, Albin Stigö > > <[email protected]<javascript:;> > <javascript:;>> > > wrote: > > > > > Hi, > > > > > > Jens, thanks for the link. Did you ever finish the app where you were > > > using these techniques? > > > > > > First I naively thought that it would be enough to hash the body of > > > what you are going to PUT/POST and then sign that hash and include the > > > signature as a custom http header. I guess this would work for > > > verifying the data on the first post but you would not be able to > > > verify the signature later if couchdb does any parsing of the > > > transported data. > > > > > > What you are suggesting using a canonical representation of of JSON > > > seems like a much better idea it also apparently what oauth uses. > > > > > > I guess this would require some hacking on couchdb. It would be really > > > neat to have a _keys database much like the _users and for for > > > documents to have a _signature field. What do you thin..? > > > > > > --Albin > > > > > > > > > > > > On Wed, Jul 4, 2012 at 3:07 AM, Jens Alfke > > > <[email protected]<javascript:;> > <javascript:;>> > > wrote: > > > > > > > > On Jul 3, 2012, at 10:01 AM, Jim Klo wrote: > > > > > > > >> Yes, and as a matter of fact, i just got digital signature > validation > > > using OpenPGP within a map function working a few minutes ago! > > > >> Here's a link to the relevant code: > > > > > > https://github.com/jimklo/TheCollector/blob/master/dataservices/thecollector-resources/views/lib/sig_utils.js > > > > > > > > As far as I can tell, this code uses a data schema where the signed > > > contents are wrapped in some kind of OpenPGP encoding: > > > > > > > >> var msg_list = > > > openpgp.read_message(doc.digital_signature.signature); > > > >> for (var i=0; i<msg_list.length; i++) { > > > >> isValid |= msg_list[i].verifySignature(); > > > >> } > > > > > > > > It looks like msg_list is the actual document payload, which has to > be > > > decoded using openpgp.read_message. > > > > > > > > This is IMHO not a very good solution because it hides the document > > > contents away — for example, all the map functions and any app logic > that > > > uses documents will have to know to call read_message, which will also > > make > > > them slower. > > > > > > > > The schema I implemented (see my previous message) doesn't alter the > > > basic document format. The signature is in a nested object but applies > to > > > the entire document contents (minus the signature itself of course). > > > There's no need to change any code that reads documents; the only time > > you > > > have to know about the signature scheme is while verifying the > signature. > > > It's even possible to have multiple signatures on a document. > > > > > > > > —Jens > > > > > > -- Bernhard Gschwantner Unser Wein G&U OG Kirchengasse 13/7, 1070 Wien mobil: +43 (6991) 971 32 96 tel: +43 (1) 971 32 95 e-mail: [email protected] twitter: @bernharduw <http://twitter.com/bernharduw> web: www.unserwein.at
