‘Blockchain’ has become a well-known term especially in light of the cryptocurrency mania of recent years. Most people have heard of cryptocurrencies such as Bitcoin, Ethereum and Litecoin, to name just three of the most well-known coins. These digital currencies are all based on blockchain technology. Fundamentally, a blockchain is a distributed database in which transactions between two nodes in a peer-to-peer network are recorded and stored in a decentralised manner. Records of these transactions, or blocks, are verified before being added to the blockchain. The blocks are encrypted before being stored, with each block containing a cryptographic hash of the previous block. Any block added to the blockchain cannot be altered retroactively without the alteration of all subsequent blocks. In view of the above, the main benefit of a blockchain is that it prevents modification of the data stored therein.

Accordingly, the attraction of cryptocurrencies is that secure transactions can be conducted between parties without requiring a central authority such as a high street bank to verify the transaction. It is questionable as to whether cryptocurrencies will supersede traditional forms of state-controlled currency issued by sovereign nations. However, cryptocurrencies are but one manifestation of blockchain technology, and there are numerous other areas in which blockchain technology can be usefully applied, such as smart contacts, banking, insurance, property transactions, healthcare and any other area which could benefit from a transparent ledger system. 

This brings us to the possibilities for patenting blockchain technology. While mathematical methods, business methods and computer programs are excluded from patentability under European patent law per se, ‘computer-implemented inventions’ (CIIs) may be patentable if they solve a technical problem in a technical manner which is novel and inventive. A computer-implemented invention (CII) is an invention which involves computers, computer networks or other programmable apparatus, wherein at least one feature of the invention is embodied in a computer program. Blockchain technology involving distributed databases therefore can be considered as falling under the general umbrella of CIIs. In order for a computer program to be patentable, the program must produce a "further technical effect" when run on a computer. A "further technical effect" is a technical effect going beyond normal physical interactions between the program and the computer on which it is run, for example, a computer program which specifies a method of controlling an anti-lock braking system in a vehicle. As a European patent attorney will know, the challenge of getting CII patent applications granted at the EPO can be difficult. However, if the patent specification contains teaching that the CII provides technical effects such as more efficient use of computer resources (e.g. reduced power, bandwidth, processing overhead, etc.) and improved security, patent claims directed to CIIs may be granted. In the context of blockchain technology, improved encryption is an example of a further technical effect in the form of increased security.

There has been a marked increase in the number of blockchain patent applications filed over the last 10 years since the advent of Bitcoin. This will be an increasingly busy field in the years to come. There is no doubt that blockchain technology may be patented, as a search of the European patent register will reveal. Nonetheless, patent applications directed to blockchain technology will be no different to CIIs in general in having to convincingly show that they are solving a technical problem in a technical manner that is novel and inventive in order to be patentable.