Application of blockchain technology
Blockchain technology, usually associated with cryptocurrencies is increasingly used in various fields, including in particular finance, energy, healthcare, securing IP rights, etc. This technology enables to store data in a safe way and is constantly evolving. Mechanisms of its operation and possibilities of application are presented in the article below.
Surprisingly, this technology was first developed in the 20th century when S. Habera and W.S. Stornett described the idea of a cryptographically secured chain of transaction blocks. Whereas in 2008, a person nicknamed Satoshi Nakamoto published the so-called White Paper, which presented ideas regarding development of blockchain technology. Nakamoto shall be considered as the father of Bitcoin although it has not been established yet who hides under this nickname.
Polish legal system does not provide a definition of blockchain technology. Therefore, it is necessary to refer to the doctrine. K. Piech defines blockchain as "a distributed database that includes a constantly growing amount of information (records) grouped into blocks and linked in such a way that each consecutive block comprises a timestamp of when it was established and a link to the previous block, which constitutes an encrypted 'summary' (hash) of its content. Since every transaction block has a reference to a previous block, it is not possible to change a transaction previously included in a block without modifying all subsequent blocks. This forms an unbreakable chain of data blocks (meaning blockchain). Thanks to blockchain, making any changes in archive records (without changing the whole history of a given transaction) is impossible.”
Structure of blockchain
According to the above definition, apart from storing a certain set of information (in the case of Bitcoin, the information relates to transactions), every block has its own unique hash- ID. In addition, the headline of each block (excluding the first one) includes a hash of the previous block. The cryptographic hash is so unique that many times its function is compared to a fingerprint. It is worth to mention that it is not possible to give two blocks the same hash and, more importantly, it is not possible to read the content of a block only knowing this ID.
Such structure makes any unwanted modifications immediately noticeable. The modified block breaks the chain continuity. A block that has been modified, changes its individual hash, and consequently no longer refers to the rest of the blocks and leads to "break" of the entire chain.
Blockchain technology is intended to counter unauthorised activity through a distributed consensus mechanism. A consensus protocol ensures analysis of whether a block should be included in the chain or not, and ensures proper chronological positioning in the chain. In blockchain, such protocol constitutes proof of work. The proof of work mechanism slows down creation of blocks and recalculates the necessary certification within the generated time window.
Another security feature of blockchain is operational resilience where one weak link cannot cause the entire system to fail. Applying the distributed system based on a peer to peer model eliminates the need for having one central server storing data, in favour of storing the same set of data by all network users.
Distributed database can be public, private or hybrid. In a public chain, the notion of the sole "owner" does not exist as anybody can download the selected part of database after installation of the relevant software. However, this type of infrastructure is not widely used by commercial enterprises. In private networks, only specific users of a given organisation have access to the data included in the blockchain.
In the beginning, blockchain technology was developed for cryptocurrencies. It should be pointed out that blockchain and cryptocurrencies are not equal. Blockchain is a tool used to record information about transactions. Currently, a wider range of areas of use can be found and various types of data can be securely stored using this technology. Comprehensive use and ease of implementation of blockchain to almost any industry is one of the biggest advantages of this technology.
Blockchain technology could potentially be implemented in land and mortgage registers. Data regarding real properties would be stored in a decentralised manner and each successive owner and their data would constitute successive blockchains. However, blockchain should be interpreted as a non-public data register and therefore it would only have a declaratory nature.
The so-called smart contracts are now becoming more and more popular. These contracts use blockchain technology, which significantly automates the entire process of contract performance.
Potencjalnego zastosowania tej technologii można również upatrywać np. w sektorze medycznym. Wszelkie informacje o pacjencie takie jak wyniki badań, certyfikaty odbytych szczepień (w tym np. szczepień przeciwko SARS-CoV-2), zaświadczenia od lekarzy, e-recepty i wiele podobnych dokumentów mogłyby być przechowywane z wykorzystaniem technologii blockchain. Podmioty lecznicze generujące dany dokument mogłyby przechowywać je za pomocą łańcucha bloków. Taka metoda zapewniłaby bezpieczeństwo, gdyż zdecentralizowana technologia blockchain powoduje, że znika ryzyko utraty danych, które jak dotąd są przechowywane w scentralizowanych serwerach. Ponadto żadne z dokumentów nie mogą ulec modyfikacjom.
Technologia blockchain rozwija się bardzo dynamicznie. Powstają coraz to nowsze platformy blockchainoweBlockchain technology develops very rapidly. There are more and more new blockchain platforms being developed. It goes without saying that it is a technology which enables immediate identification of any modification attempts and ensures a high level of data security while eliminating the risk of failure at the same time, which gives great opportunities for potential applications in various sectors of economy.
 K.Piech, Leksykon pojęć na temat technologii blockchain oraz kryptowalut. Strumień „Blockchain i Kryptowaluty” programu „Od papierowej do cyfrowej Polski”, 2016