Using Blockchain for journalism source verification and reputation.

by Hugo O’Connor

As part of Project FiveArm’s methodology, we are developing a blockchain integration that enables  portable, anonymous, and secure credibility ratings of source material.  Project FiveARM’s Hugo O’Connor explains.

Cryptography, the field of study concerned with information security, confidentiality, integrity, and authentication, provides a powerful set of tools. This toolkit has been looked at with renewed interest following the tremendous ascent of cryptocurrencies such as Bitcoin.

A cryptocurrency is an example of applied cryptography that combines a currency with a payment network, enabling peer to peer transactions. More money has poured into the cryptocurrency ecosystem, than the early days of the world wide web. The innovation that enabled these peer-to-peer, decentralised monetary systems is a technology called the blockchain.

Blockchain presents unique opportunities to apply some of these technologies to the intensifying issue of ensuring that source material from independent journalists, witnesses, stringers and frontline defenders can be trusted.

What is the Blockchain?

The blockchain consists of groups (blocks) of transactions, each cryptographically linked to the preceding group of transactions. Blocks are written into the sequence through a process of many nodes or computers searching for a nonce (a random bit of data, or arbitrary number).  When combined with a group of transactions, it can produce a hash (a hash being a one-way function that produces a unique fingerprint from some data) lower than a given value, that adjusts depending on the combined amount of computing power on the network.

As there is some work required, computer processing cycles and therefore electricity, to produce each hash, the system is known as proof of work. The node that produces this ‘golden’ nonce is rewarded with some amount of newly issued cryptocurrency, and this reward provides an incentive for the participating nodes to take part. The longest chain of blocks serves as proof of the events witnessed by the network.

One way of thinking of the blockchain is to consider it as a world computer. Whereas we are used to the paradigm of one computer per person, the blockchain introduces the paradigm of one computer per planet.

The ‘world computer’ paradigm has obvious application for the financial sector, for example, as we can now have some value state that cannot simply be copied and pasted between computers. This state could represent tokens for a monetary system, or any other finite financial resource, such as stocks or bonds.

How can Blockchain serve journalism needs?

Only recently has the discussion moved to how this technology might address some of the challenges facing journalism.

The first area that comes to mind is identity. In most circumstances, journalists require a secure channel to communicate with their sources. Public-private key cryptography can provide a way for sources to encrypt their communications with journalists.

What it can also provide is a means for sources to sign their messages in a way that can be cryptographically verified by any other party with that source’s public key component.  That a piece of information originated from the person in possession of a particular private key can be proven. In this way, it is possible for sources to be completely anonymous yet for journalists to build an identity for that source based solely on the information they have contributed over a period of time.

The second area is to do with integrity of records. The blockchain offers a cryptographically auditable history of the state of some set of records stored on it. With Bitcoin, for example, it is possible to trace the spending of an amount of bitcoin right back to the genesis of that bitcoin when it was created in a coinbase transaction as a reward for a particular node solving the proof-of-work challenge. If the FiveARM field data records were to be stored on a traditional database, there is a risk that some malicious actor could obtain access to that database and alter the records. When records are altered on the blockchain, there is a history of the record state. Furthermore, we have a good way of timestamping records, to prove that something existed on a particular date. It is also possible to configure a network in a consortia of trusted nodes, such that the information contained in these records would only be visible to trusted parties.

The third area is around source credibility. The web of trust is a powerful idea first proposed by Phil Zimmerman of PGP fame, that provides a decentralised trust model to establish the authenticity of the binding between a public key and its owner. This web of trust model could be taken with the identity keys of various sources to make some statement about the credibility of that source. Source reputation would provide a useful contextual and reliability filter in environments where there is a lot of information pouring in, much of it from new or unclear sources.

Persistent source identity, record integrity and source credibility are just a few of the possibilities enabled by not only the blockchain but cryptography in general.

Project FiveARM’s source reputation blockchain solution

Our proposed source reputation blockchain seeks to integrate these technologies to create a system for rating source and source material credibility. While the blockchain is a decentralised technology, and within the community there are several efforts to create a decentralised reputation system, credible news gathering is necessarily hierarchical with news editors ultimately bearing the responsibility for publishing credible and factual news.

As such, our reputation system is anchored by a root key pair belonging to a particular news organisation. That root key can appoint other organisations to the consortium blockchain, granting such organisations permission to write to the source chain database. Editors from those trusted organisation can then appoint journalists to carry out the task of rating source material.

We propose a checklist, that creates a score for the source material based on several aspects. The credibility of a source would be a reflection of the credibility of the material they contribute over a period of time. The simplest approach would be to average the scores and to map that value to a given range.

These ratings could be written into a smart contract on the Ethereum or Hyperledger blockchain. The source identifier would be their public key. The identifier for each piece of source material could be a hash of that data.

Storing this information on the blockchain would open the possibility for collaboration between news organisations, as various participating new outlets contribute to the credibility score of a particular piece of source material, and thus the credibility of the related source.

Project FiveARM is currently exploring these possibilities, and developing a Proof of Concept.   We welcome and invite contributors, collaborators, ideas and feedback – especially those with blockchain and coding experience.

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