Data provenance tracks the origin of information with the goal of improving trust among interested parties. Data provenance is an important requirement for a range of applications such as food safety, supply chains, and tracking of epidemic outbreaks. Many of these applications are inherently distributed and require high levels of privacy and trust.

Fog computing and Blockchains are recent technological solutions that were born from advancements in cloud and distributed computing. Fog focuses on bringing the cloud closer to the edge user while Blockchain provides transparency without the need for a trusted centralized entity. Both can be complimentary as Fog spreads the data and computer storage while the Blockchain can keep it consistent and trustworthy. These technologies can be used to improve several aspects in a Data provenance context.

In this paper we describe an architecture that allows the tracking of data provenance in a wide-area distributed fog. While we employ blockchains to provide transparency, localized Fogs have control over what is made public on the cloud. The architecture proposed in this paper enables fast and reliable data provenance for clients executing in the Fog using software services that keep the information consistent across all interested parties in the cloud. Any information in the system is associated with a proof of authenticity, but authors have control over the eventual publication of the information.

Our proposal was built upon the well established provenance model W3C Prov, which simplifies adoption of the framework.

We developed an application consisting of a client and web services that is able to store and share provenance information using open standards in a blockchain. The relate work, architecture and performance tests for the proposal are presented here.