Proof of origin is more than a mere copyright issue - which is chiefly of interest to the creator of the document and which we deal with here.
If you walk into a shop with a wad of banknotes, you want to feel fairly confident that they were created by the authorised bank. It is part of the anti-counterfeit "chain of custody" protection. If someone sells you a new DVD player, and you want to be sure it is "kosher" and that warranties will be honoured, you need to know where it came from - or at least who is accountable for it. Similarly, in the digital environment, when you receive a contract, a purchase order, a complaint or praise, a public key, an encrypted message or indeed any other important document, you need to be fairly confident that you can verify its source.
There are two levels of Codel protection for document origin. The first and simplest is the registration of the document and its associated claims on the Codel protected audit trail. We also reserve space for optional one time keys generated by the authors as a means of proving - subsequently - that they were the source of the submission to Codel. Neither of these categorically provides proof of authorship - any more than does a current copyright claim. All it can do is provide a means of verifying the primacy of a claim; that the claims - including authorship - for any document must have existed at the time of Codel registration. Consequently, any challenger claiming earlier copyright would have to produce similar evidence for that earlier claim. In most cases, adequate evidence of priority of claim is considered sufficient proof of origin.
However, in validating the source of electronic communications, with a view to sustaining potential legal challenges which may arise from disputes over the detail contained in that communication, it is necessary to provide much more rigorous evidence of the origin. It is not enough to show that a document must have existed at a certain time and that a certain one time key holder can prove they submitted it.
To begin with, in a dispute situation, the originator of the document might not be inclined to prove their authorship. So the recipient must have a means of proving it independently. Similarly, a recipient might not be inclined to admit having received a given document, so the sender needs an independent means of proving receipt.
Codel deals with this knotty problem by introducing this robust protocol.
