In December 2018, a child named Divit was given a birth registration certificate prepared using blockchain by the New Town Calcutta Development Authority in West Bengal. The data of the certificate prepared in this manner cannot be altered improperly. One significant example of this is the application of blockchain for citizens in India. States like Andhra Pradesh, Telangana have also started using blockchain for health, land and birth registration, online purchases by the government and so on. The common question is how is the internal structure of the blockchain? What are its main components?

A blockchain is a list of ordered and linked blocks. Each block has two parts – the header of the block and the body of it in which multiple transactions are written.

Transactions by users are recorded in the block as a transaction. The data contained in each block, such as the heading and the set of transactions, are calculated using the SHA256 cryptographic ‘hash’ algorithm, which is a complex mathematical process. As the key is needed to open the closet or box, the block needs a hash to read. The hash is made up of 32 bytes. In the header of each block is noted the hash of the block next to it, the own hash of the block, at which time this block was written or modified. The next block is called the parent block. Each block has only one and only parent block. The link here is similar to the ‘next block hash’ link or link to attach the newly created block to the next block, so that the newly created block is joined using a link to the next block. Thus, multiple blocks are linked together using a link to form a chain.

The first block is called the Genesis block, and then the next block links to the block exactly ahead of it. As shown in the figure above, the last block of the blockchain, the most recent block, can be moved backwards to the first block – the Genesis block. This way the information contained in all the blocks can be read. Blockchain can be saved as a simple file or data base.

Any minor changes to the part data of a previously written block are immediately recalculated using the hash SHA256 cryptographic ‘hash’ algorithm of that block. Suppose that the data in block # 1 was slightly modified. So the hash of that block will change. This changed hash must be modified as a ‘block next to the hash of the block’ in the block next to block # 2 and this will change the hash of block # 2 itself. Now the ‘hash of the next block’ field in block # 3 must be recalculated and reformed. Thus, all the next blocks, starting from block # 1 to the end, will have to be modified, which will have to do a huge amount of computational calculations. This will require a powerful computer as well as electricity to operate it. Here, it becomes clear that if a blockchain has multiple blocks and any part of the initial block has to be modified, that task becomes very difficult.

The concept of blockchain is comparable to geology. As the top two to four inches of the surface of the soil changes gradually depending on the changing season, the soil geography does not change or remain stable for centuries, just like in the blockchain, there is an improvement due to the recent rotation of a few recently written blocks. According to one conclusion, the top six blocks in the blockchain are seen to be changing, but the blocks below hundred or thousand or so remain as stable as the lower levels of geocache.

For example, we take hospitalized patients and their transactions with various agencies. The patient has to make transactions with doctors, laboratory, drugstore, hospital, blood bank, insurance company, etc. If the hospital is operated on a hospitalized patient, the hospital will have all the records, but it should also be reported to the insurance company. If a patient is examined for his blood in a blood bank, the report should be reported to the doctor, hospital, insurance company, etc. Thus, if all the relevant units were to be transparently reported on the various medical treatments being performed on the patient, the medical history recorded by the treating doctors, hospital operations, the medicines provided by the drugstore or the expenses incurred to the patient would have to be done under the contract. Payments as well as all records related to them can be recorded in the ledger of the blockchain Hey. You can keep a copy of every ledger here.

The main thing here is that when the operation is done by the hospital, it will have a note in the hospital ledger, but unless all the relevant units of the doctor, blood bank, insurance company, drugstore etc are officially authenticating the transaction regarding the operation, the ledger is near all the units. The copy will not have a note on it. If all unit ledgers have to record patient operation records, consent should be given to all units. All units or users of the blockchain have the protocol to consent to the transaction by which the transactions in the blockchain are officially authenticated. This is because of the transparent information that users associate with that method. Because of this, there is no place for transparent information that can be accessed by users connected to that system, as well as for any obscure or incorrect information.

As mentioned in previous articles, computers that are part of the blockchain, transacting and keeping a copy of a shared ledger are called nodes, and there are three main types:

  1. Full node:which implements all blockchain rules in a rigorous manner, which implements a smart contract on transactions made by users. Full node has a copy of the entire blockchain database, ie ledger. The hospital, blood bank, drugstore, insurance company, doctor, etc. mentioned in the above example can be viewed as a full node.
  2. Light Node:It receives transaction details from the full node and stores the transaction to a certain extent.
  3. Minor Node:is a full node and processes the process of officially attaching the blockchain to the blockchain as it is filled with transactions.

The blockchain is divided into four types based on its usage:

  1. Public Blockchain:Anyone in the world can read the data written in the blockchain, send the transaction, and, if agreed, the transaction can be approved. Bitcoin, Ethereum, etc. are an example of a public blockchain.
  2. Private Blockchain:A blockchain typically created for a single company or group in which only a predetermined user can send or share information or transactions.
  3. Permitted Blockchain:Here only some users and groups are allowed to authorize transactions as part of the blockchain. The main purpose here is to provide additional security. An example is a cryptocurrency called Ripple.
  4. Consortium Blockchain:Although it is a private blockchain, it is here that more than one company, rather than just one company, is formed for its own group. All members or nodes here have the node allowed to authorize the transaction, while all other members of the group can read it.

Recently, Sanjay Dhotre, Minister of State for Electronics and IT, Government of India, has said that a document is created to provide the necessary infrastructure at the national level in view of the various appropriations of blockchain and its capacity. Research on the ‘Distributed Center of Excellence in Blockchain Technology’ project along with organizations such as C-DAC, IDRBT, etc., is working on an experimental basis, which is funded by the Ministry. As part of this project, property registration has already been done on the basis of blockchain in Shamshabad district of Telangana state. The Center will set up a blockchain framework to test various digital assets or documents such as certificates issued by universities, sales documents prepared by companies or companies, registration of vehicles or hotels, etc. Such a framework will be an important guide for software companies to use blockchain in various applications.

Dr. Sheshang D. Degadwala

Head of Computer Engineering Department

Sigma Institute of Engineering