BLOCKCHAIN & DISTRIBUTED LEDGERS
A distributed ledger is essentially an asset database that can be shared across a network of multiple sites, geographies or institutions. All participants within a network can have their own identical copy of the ledger. Any changes to the ledger are reflected in a matter of seconds. The assets can be financial, legal, physical or electronic. The security and accuracy of the assets stored in the ledger are maintained cryptographically through the use of ‘keys’ and signatures to control who can do what within the shared ledger. Entries can also be updated by one, some or all of the participants, according to rules agreed by the network.
Underlying this technology is the ‘block chain’, which was invented to create the peer-to-peer digital cash Bitcoin in 2008. Block chain algorithms enable Bitcoin transactions to be aggregated in ‘blocks’ and these are added to a ‘chain’ of existing blocks using a cryptographic signature. The Bitcoin ledger is constructed in a distributed and ‘permissionless’ fashion, so that anyone can add a block of transactions if they can solve a new cryptographic puzzle to add each new block.
BUT THE TECHNOLOGY IS NOT ABOUT BITCOIN
It is about the algorithmic technologies that enable Bitcoin and their power to transform ledgers as tools to record, enable and secure an enormous range of transactions. So the basic block chain approach can be modified to incorporate rules, smart contracts, digital signatures and an array of other new tools.
Distributed ledger technologies have enormous potential in a variety of public and commercial applications. They can help governments to collect taxes, deliver benefits, issue passports, record land registries, assure the supply chain of goods and generally ensure the integrity of government records and services. In the public health sector, the technology offers the potential to improve health care by improving and authenticating the delivery of services and by sharing records securely according to exact rules. For the consumer of all of these services, the technology offers the potential, according to the circumstances, for individual consumers to control access to personal records and to know who has accessed them.
Existing methods of data management, especially of personal data, typically involve large legacy IT systems located within a single institution. To these are added an array of networking and messaging systems to communicate with the outside world, which adds cost and complexity. Highly centralised systems present a high cost single point of failure. They may be vulnerable to cyber-attack and the data is often out of sync, out of date or simply inaccurate.
In contrast, distributed ledgers are inherently harder to attack because instead of a single database, there are multiple shared copies of the same database, so a cyber-attack would have to attack all the copies simultaneously to be successful. The technology is also resistant to unauthorised change or malicious tampering, in that the participants in the network will immediately spot a change to one part of the ledger. Added to this, the methods by which information is secured and updated mean that participants can share data and be confident that all copies of the ledger at any one time match each other.