CLink Marketplace


A digital marketplace1 enables parties to buy and sell digital content of any kind, and to trade in rights for the content. The growth of NFTs has seen a corresponding growth in the appearance of digital Marketplaces for individuals to buy and sell.

A trustworthy Marketplace will identify and authenticate the products, the buyers and sellers, and be clear what rights if any are being traded along with the content. It will provide a record of the transaction and a mechanism for conflict resolution. This post describes CLink’s Marketplace through a case study, and first summarizes CLink’s new C2PA authentication processes.

CLink Authentication with C2PA

In the past year, we have spent much time enhancing the user and content authentication technologies for the CLink platform. CLink became an active contributing member of the Coalition for Content Provenance and Authenticity (C2PA) and is one of the earliest implementers of the C2PA specification.

C2PA was formed in 2021 by leading technology and media companies with the aim of tackle disinformation in digital media and the digital news ecosystem:  

C2PA unifies the efforts of the Adobe-led Content Authenticity Initiative (CAI) which focuses on systems to provide context and history for digital media, and Project Origin, a Microsoft- and BBC-led initiative that tackles disinformation in the digital news ecosystem.

C2PA provides an unprecedented authentication technology that online commerce and digital value chains can benefit from: integrating this into the CLink platform was an obvious choice.

A CLink Marketplace Case Study

Gulzar created an image by combining two ingredients with Adobe Photoshop, a C2PA-enabled software.2 Photoshop automatically authenticated the image by creating and embedding3 cryptographically-bound assertionsclaims, and manifests.  Photoshop also authenticated Gulzar by a verifiable credential that became one of the assertions4. The image was attributed to Gulzar as the author in the CreativeWork5 assertion.

The image and the corresponding rights were registered in the CLink ledger, which automatically assigned persistent identifiers6. Additional identifiers7 were created in the ledger object of the image8 to facilitate a reverse image look-up service. The CLink ledger is accessible to the public.9 

Before the image was listed on the Marketplace, Gulzar was verified by his ISNI number as an additional means of authentication.

A programmatic license offer was applied to the image using Gulzar’s CLink licensing profile, the license information was written in the ledger and also synced to the embedded metadata of the image, including the properties required to display the “Licensable” badge in Google Images.

An ISO-compliant archive of the image with preserved metadata10 was created. This provides a means to detect changes to the image during its lifecycle.

The image was listed at the Marketplace. The listing provides a UX with progressive disclosure to the viewer starting from a simple indicator all the way to forensic-level data at the discretion of the viewer.

All the above steps were automatic once Gulzar had submitted the image to be registered and licensed in CLink.

Janos decided to buy the image and clicked the “Buy Now” button. After he was authenticated, he was presented with a license offer. Once he had accepted it and made the required payment, the image was delivered to his Content Management System (CMS)11 and he republished the image. The electronic records of the transaction – including the executed license – were created in both Gulzar’s and Janos’ CMS. The republished imagelicensed rights, and the rights transaction have been registered in the CLink ledger12.


A case study of the CLink Marketplace for authenticated content from verified rights holders has been demonstrated.

Your comments, feedback, and criticism are solicited and sincerely appreciated.

  • 1 Rights associated with the content are a key concern. The ecosystem facilitating transactions should ensure the transaction and contemplated use are non-infringing.
  • 2 C2PA features in Photoshop version 23.1.0 used in the case study are in Beta.
  • 3 Note: the content of the linked page loads in multiple steps showing the progressive levels of the UX.
  • 4 Supra fn. 3
  • 5 Supra fn. 3
  • 6 CLink follows the Principles of Identification described in  and allots persistent and immutable identifiers to the ledger objects by The Handle network is a proven, scalable identifier system used in major commercial ledgers such as ISBN-13DOI , and EIDR.
  • 7 In this demonstration no new C2PA manifest was created when the ledger objects were recorded. That feature will be available in a subsequent release.
  • 8 “ISCC – Content Identifiers,” accessed January 20, 2022,
  • 9 These identifiers – like the persistent identifiers – are also synced to the embedded data of the image
  • 10 Supra fn. 7
  • 11 In this example the CMS is WordPress.
  • 12 Supra fn. 3

Provenance and rights