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WebDSign: abstract

WebDSign: thrust the Web by trust

A French summary exists: résumé en français.

This document describes an approach which offers a way for the Web user to obtain various informations about an online document:

WeBDsign transforms data published on the grafitti-wall-Web into rock-solid information. It derives authentication of documents into authentication of information (thanks to ooper for this one!).

The proposed logic does no check itself any document, it only produce certificates and seals (they are common task) and gather informations about published seals (which certificate created it? to which document is it attached? where are the emitted opinions/critics?...), sent by the tools used by their authors to create them. A browser extension will inform the user, for example, about how people he trusts judged whatever he is reading.

The goal is to convey "real life" trust on the Web, thanks to seals describing and protecting information. WebDSign does not create confidence or trust by itself, it simply let anyone will be able to create a seal. Each seal establishes one or more of its author's statement about a given published information, therefore each seal expresses a relation established between its author and the information sealed:

Project status

As of the beginning of 2008, WebDSign is (since 2002) a set of concepts and a few snippets of code.


Don't miss our slides.

Some benefits

The proposed method:


WebDSign was exposed and discussed at Cambrian House

Cambrian House, Home of Crowdsourcing


A 'atom', here, is a chunk of information published on the Web (i.e. storable into a correct (valid) XML node).

Each is meant to be quoted, if possible in full form. That's because no one wants distorted quotes, no one wants to be quoted off-context (you say "I agree with John when he says that the sun shines" and people quote John saying "The sky is green" then your sentence truncated to "I agree with John". Ouch!). Therefore each and every WebDSign atom is coherent, it is an 'atom', created and sealed by its author. Each atom can be of any length and can quote other atoms, or (for non-repudiation purposes, therefore in order to forbid the criticized author to withdraw his words) even integrate a copy of some of them. The easy (and 'default') way is to seal while publishing is to seal the whole document (web page). All the necessary signature functions are done by the authoring tool: the author selects an atom (by highlighting it, as usually done) then clicks a 'seal' button (he has to have his certificate on the machine and to type, once per session, his passphrase), he then can express wether he wants to only sign or to give an opinion about it, certify it...

A certificate (short for 'digital certificate') is a digital piece of information enabling someone to be identified and somewhat described.

A certification authority signs certificates, injecting into them some dematerialized trust.

A seal (short for 'digital seal', used here as a replacement for digital signature) offers here an efficient way to express that a given identified person (she uses a certificate in order to seal) expresses some opinion about an information (for example "I'm the author" or "this is true") in a way that, thanks to some cryptography, anyone can be quite sure that this person (not anyone else) sealed this particular information (which was not tampered with).


From an authors standpoint: in order to publish trustworthy information on the Web you have to let the reader be pretty sure that you wrote it and that the document he reads is exactly what you wrote. You may also want to be able to prove that you was the first to publish it. Moreover you may want to show who agrees or certifies the information, and anyone expressing such a comment (from a mundane comment à la weblog all the way up to database-powered scientists' peer-review) may want to publish it for any interested party.

WebDSign can deliver all those insurances. To do so it specifies conventions and tools enabling any atom of data (text, images ...) to be published, for example by a Web or RDF server, along with meta information which seal it in order to convey all those warranties.

Any browser will be able to interpret, check and (upon successful checking) present any sealed information as such, for example by displaying it on a graphic box using colors revealing the type (statement: origin, agreement...) and author of the seal. The reader may then obtain some related information (who guarantees the seal author identity...).

Any real human can obtain a well-signed certificate (right now: a PGP-GPG key), right now and for free. It can be used, through WebDSign tools in order to create a seal and then to publish it.

Any seal can be accepted by the information publisher and therefore published on his site, along with the information. Any visitor will obtain it.

Some information publishers may not want to publish, along their own documents, seals about it created by others in order to criticize, for instance because they may express 'I disagree' or 'This information is false'. Therefore any seal can also be published on a seal-publishing server, for all browsers to use it (as a layer) in order to present those seals when appropriate, i.e. when reading the sealed information.

Any action (seal creation, exploration, publication configuration...) needed to create or maintain a seal will be performed through a standard document authoring tool or browser.

Any Web user can configure his browser in order to ignore some sealers (certification authorities, particular certificates).

A user may configure that only his own seals are to be taken into account when calculating the score of a sealed document. He may also let it take into account people he respects and trusts (let's call them 'friends') seals. And even their friend's ones. Some will want to use coefficients, upon the 'distance' in this chain of trust, or for given individuals, or with respect to the topic. Or ignore any seal produced by somebody only criticizing him (or his friends). Some may want to give confidence to seals of people working in a given university, political party, whatever (and their friends... or not). Some may edit official lists of trustable certificates, for you to adopt (or not). There will be a standard and sound configuration, inherited from existing 'web of trust' models, and everyone will be able to tweak it, even on-the-fly (you read something cool, you search other documents by this author, coolness is at max, you configure your trust to him at a fairly high level. Some of your friends, who decided to give trust to whoever you trust, will automatically trust him/her, maybe a in a somewhat lesser extent because they want some damping/decay during such inheritance).

A user also can enable people he trusts to filter the Web for him: he will be warned upon access to a not or badly appreciated one. His browsing experience is somewhat 'layered' by other's.


To do so we will use XML-Signature (RFC 3275), which uses OpenPGP and X.509.

The existing virtues (or pitfalls) of the underlying schemes will be available:

Moreover, using existing and open (publicly available) approaches leads to a development benefiting from existing code and certificates.

Misc technical considerations

An adequate Web browser will:

Any atom can have multiple seals, even overlapping. Any seal producer can seal the very same atom multiple times. He can use expirable seals and also instantly revoke a seal (it will not be restorable afterwards).


Here are some descriptions and ugly-but-commented pseudo-snapshots, presented for each 'role': 'author', 'evaluator' (emitting opinions), 'reader' (browsing the Web). Any WebDSign user can freely embrace any role at any moment.


The authoring tool let him save a document which is automatically sealed in order to sign it (claiming "I'm the author") and to preserve its integrity. Clicking on a menu item or button seals the currently selected zone(s) of the document. The authoring tool, while uploading on the website (for publication), communicates to the WebDSign central site various informations about the seals and publications URLs. Each seal has an ID, calculated at creation time (without involving the central database).


(He is a 'reader' then...) He wants to comment the document displayed or selected. He selects the corresponding seal or, if there is no seal, creates one (a dedicated type dubbed "I saw this"), then chooses a WebDSign browser extension button or menu item launching the function "Create an opinion", then sees a WebDSign window or frame containing: If he doesn't provide any material the seal is not created.

This describes the standard opinion 'template', other ones may be created by every user by copying an existing template then adding fields to it. An opinion template for texts, for example, may also ask whether the contents are exhaustive (covering all pertinent material), accurate (clear, articulated...) and brief (concise).


A 'reader' is a WebDSign user who is just browsing (and may instantly become an author or evaluator).

Here are a 'reader' browser's potential way to display seals. An ideal extension will offer many customizable ways to do it.

Any WebDSign-ready browser offers a menu offering at least:


Here is a atom (part of 'page') published on the web, without any seal:

A atom of this document is 'signed', as revealed after launching the 'enrich' function of WebDSign (which may be always activated), by a red border which means 'this information has an author and was not tampered with':

atom signed

By clicking on the red border (or on some graphic handle conveniently provided) the visitor will gain access to a document generated by his browser (we do not provide any mock-up here), stating various pertinent information (who signed, when, who signed the certificate used...).

The atom certified ('truthness', revealed by a blue border) by 2 known parties and 8 unknown ones:

atom sealed (trust)

A click on the border will (as usual) let the browser display various informations about those seals.

Atom sealed as above plus sealed in order to express 'I agree' (green border) by 0 known, 3 unknown and 4 untrusted:

atom sealed (trust, agree)
Note: those seals apply to the information, therefore a border included into another is not sealed by it (i.e. those snapshots show seals sealing information, not seals sealing seals).

Seals may apply to seals, in such a case the corresponding boxes will be linked.

By clicking on a border the visitor will access to a set of linked documents created by his browser in order to describe the seals.


Any seal can express at least one of the following assertions:

Authorship (signature)

It means 'I am the author of this particular atom of information'

It is always coupled to a seal, meaning 'I am the author of this seal'

Done by providing a cryptographic mean to prove that [s]he is the author of this particular atom (therefore also providing a way for anybody to check that the document was not modified).

Application: fighting against astroturfing

Anyone can use his certificate to seal any atom written by him/her in order to prove that somebody (as opposed to an empty digital ID) stands behind his published statements (for example a comment posted on a blog).


A service may provide seals (with legal value) establishing the publication date and the signing certificate. It can charge for it (there is a biz model here).

Application: creating proofs of origin and first publication date

Anyone may thus establish the origin and publication date of a published information.


This particular seal means 'I agree with this information'. It may useful for voting purposes.

Application: electronic voting

This is a can of worms but direct democracy may progress if any web user can publish a petition and gain certified signatures, proving that it attracts sympathy which anyone can automatically measure with respect to the certification authorities he trusts. This leads to concerns, for example about the representative character or even the adequacy of direct democracy, well above the topic.

Expert seal (certification of truthness)

Experts may seal part of a atom in order to convey to the reader a certain degree of trust-confidence, stating "this information is true, I put my reputation on it". He can also state that he does not agree or that is has no opinion (the mu state).

Any seal can only be produced by somebody using a certificate browser will let the user declare the certification authorities he chooses to trust or distrust. On the client side it will govern the rendering (display), on the server (for example Apache) side it will govern the acceptance ('automatic', 'spool for manual checking' or 'reject') of submitted certificates, which will in turn be published along with the pertinent atoms.

Each atom of published information sealed by a trustable (as configured) entity will be displayed in order to let the user know that it is sealed, and access to a document describing all seals: meaning (agreement, timestamp, validation by an expert ...), author (and the corresponding trust tree), date...

Application: approval/certification

It may be used by an expert, for a document published online authored by somebody willing to manifest that at least an expert agrees.

Seal publication

Anyone using a browser and a certificate will be able to produce a seal. By default the seal will stay on his machine which may publish it.

Anyone can declare to his/her browser the URL of a server publishing the seals of trusted sealers or group of sealers. The browser will then present these seals.

A seal can also be submitted to the publisher in order to be published along with the atom. Any publisher will be able to choose whether his server will host and publish any certificate. This tedious process can be eased by letting the publisher elect some seal producers to be automatically rejected or accepted (and some filters may be provided by seals publishers).


The seal-publishing server can be a Web server, using a specific protocol able to grok an URL submitted, disambiguate it, then provide a list of pointers to the corresponding seals.

Seal revocation may be resource-hungry if it implies that each and every seal is somewhat OCSP'ised. A cache and a manual 'confirm' procedure implemented in the browser may tackle this.

The 'layers' implementation is difficult because it needs some unique address for a given atom, but some of them may be published under more than one URL. We cannot use the atom's digital fingerprint as an ID because when browsing the browser only has the document, not the atoms (and any document has a huge number of potential atoms).

Pertinent information

A potential application: Wikipedia

Our objectives are: In order to do so each Wikipedia article may have more than one status, optionally used and displayed:


Wikipedia is a success because it has many good articles

Experts on any field are such because the are recognized

If Wikipedia delivers a 'Wikipedia expertise score' which gains popularity then many professional experts on various matters will be interested in obtaining a good score, in order to let prospects and customers know that their knowledge is recognized everywhere, even on Wikipedia. It will motivate experts to write and validate articles thanks to a challenging approach

A 'Wikipedia expertise score' will be delivered to every Wikipedia-account owner who writes at least an article. It will be a cryptographic certificate holding a value (the 'expertise score'). Any expert will be able to publish his score (certificate) and anyone will be able to verify it because it will be digitally sealed-and-signed by the Foundation managing Wikipedia

A contribution (information created by a given Wikipedia account) will be considered as be good if it read by many. Moreover every expert can validate or challenge it. The first validator of a given article gains a whole lot of points, the next one gains less, and so on. The best way to be the first validator is to write the article, and any expert has available material for this, therefore he can do it and will earn (recognized expertise score) from doing so

Any expert finding a factual error (validated as such by many others) will take a good fraction of the points earned. Any expert claiming he found an error then failing to obtain validation of this claim by other experts... will lose points.

Therefore the articles will be created, maintained and reviewed by a pool of score-seeking experts:

Pitfalls :


Any Wikimedia visitor will be able to state in his profile that, upon reading, [s]he wants to obtain the last version of any article which reached a given status. If there is no such version the immediate 'lower' status will be published (this is recursive)

This will not in any way annoy the reader who does not care about article status because the default (in the personal profile (preferences) of each registered user or for anonymous ones) will state 'raw'. Moreover on each article displayed a new tab will offer access to the various other accessible versions

Those various articles status will be expressed by cryptographic seals. It is not mandatory as most functions proposed here can be implemented using standard version-tracking tricks (taging, branching...) but some people may want to have their screwed articles published with a forged status and try to tamper the servers or network connection. Let's integrate security concerns as soon as possible (more about this).

The WebDSign protocol may be the technical foundation of such seals.


All processes (requesting-delivering-managing certificates, sealing, obtaining information about a seal...) will be done by a Web navigator, as 'transparently' as possible.

In order to produce a seal one needs a digital certificate (X.509 or OpenPGP (PGP-GPG)), delivered (X.509) or signed (PGP) by a certification authority (CA), which will be Wikipedia organization. Anyone can check that a given certificate (and all information it stores) was issued by a given CA.

Any account owner (i.e. any non-anonymous Wikipedia contributor) will carry only one Wikipedia certificate, which will store many attributes stating various useful parameters.

'raw' status

Default status of any article

'unpolluted' status

Any administrator (or 'RC patroller'?) will obtain a certificate in order to let him/her give the status 'unpolluted' to any article which does not contain anything blatantly off-topic.

'validated' status

Using the existing (today!) set of articles an automagic analysis of the volume of information produced and its relative stability ('unpolluted' status, age and amount of readers) the motivation and efficiency of all their authors can be calculted ('scored'). Therefore a software can establish a 'confidence score' for every already registered author.

Administrators will deliver certificates to authors obtaining the best scores. Every certificate will be qualified by an attribute (named 'wpexpert' ) listing the name of the categories of expertise of their carrier (themes, for example 'mathematics' or 'geography'), which are the very main categories of the articles they contributed to. Those authors, in turn, will recognize some other authors (for example newcomers) as peers.

As M. Subramanian puts it: any 'stable' status is to be dropped when an unexpected ongoing event happens to the subject of an article.

'expertised' status

In each category this first college of 'wpexperts' will be enabled to form a college in order to elect world-known 'experts' of the field. The CA will produce certificates for them, with an 'expert' attribute storing the pertinent categories names. At first they may be not very interested in participating but as more and more will somewhat do emulation will raise their involvement (Wikipedia will benefit from it).

Future version

As each article contains atoms (chunks) of information further developments may enable the underlying software (Mediawiki) to dynamically build every article by using the last version of every atom corresponding to the visitor's preferred status. This implies some way for the contributor to declare interdependancies between atoms.

Business model


For authors wanting to be immediately recognized by the central system. They can buy one elsewhere or even create it but buying it at the central site will enable them to be recognized under their real identity (this is useful for experts, journalists...).

Technical note: we will offer all pertinent PKI-related services: centralized (default) and decentralized (sort of escrow enabling for example a company to recover/revoke a certificate misused by an ex-employee) modes, 'n of m' (certificate issued to a group of 'm' members, only usable if 'n' members agree to do so)...


Certificates issued by third parties (certification authorities, for example Verisign or an in-house PKI) will be honored by the central system as providing an identity proof

Any standard (X.509) certificate will be recognized and used but WebDSign will not guarantee identities not certified by a certificate issued by its central system or by a cross-certified authority. Even anonymous users will know the central site and therefore may be more confident to buy there (through some anonymizing apparel), without disclosing their identity and at a bargain.


For authors wanting to be able to prove that they were the first to state something we will sell a service 'you send the atom, we add timestamp to it then sign the whole'. In fact we will use existing timestamping services, recognized by various jurisdictions


The 'alert, something you criticized/liked/disliked/whatever changed!' service, not tied to any action/dissimulation of the information publisher. Think 'sort of RSS able to automatically alert after a modification even if the author does it discreetly, without announcing anything', if necessary with filters (distinct alerts for different modifications types/authors/...)


The 'layer' enabling users to let browsing benefit from opinions emitted by people they trust. Some basic functions, for example 'Browser, show me the list of all documents liked by my pals' will be free. The function is similar to StumbleUpon's but forbids pollution (for example astroturfing). Enhanced stuff will lay on collaborative filtering and be an invoiced option.

And also...

There are other underlying money-making projects, for example specific voting or decision-making systems, experts guilds...



Thanks to Benjamin Sonntag, Tristan Nitot, Jean Peyratout, Satya Subramanian, David Latapie, Karl Dubost, Eric van der Vlist, Sbi, WJ and some of the Cambrian House folks (the site masters, Kevin_Cox, tlyden, ooper, PeeJayEl) for their useful inputs on this matter.

Thx to the guys from the PGP, OpenPGP, GPG, W3C and Apache projects who already described or even realized most of the necessary tools and protocols.

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