Reassuring QA for Smart Contracts in Decentralized Applications

Today, the world of technology is ruled by blockchain. Though blockchain is not very new, it took pace in 2011 when the first blockchain explorer was introduced followed by a cryptocurrency wallet that accounted for 28% of bitcoin transactions between 2012 and 2020. Today, blockchain and cryptocurrency are tightly associated with decentralisation.

With the various benefits of decentralisation, most importantly the need for a central authority to govern the rules being eliminated, more and more people have started relying on blockchain for investments, borrowing and lending money and other related transactions. Blockchain ensures the privacy of your information and gives you the liberty to choose who will have access to how much of your private data. On the other hand, it also ensures the data you receive on the systems are pre-verified from authorised agents.

The entire world of blockchain works on the system of cryptography – a method that uses digital signatures to give access to only those with authorised access to VIEW your data. The point to be noted here is fact that other users in the world can only view your data but cannot make any changes because of its tight integration and chained cryptography. To simplify, let’s understand the structure of a blockchain first. Visualise it as a chain of data that binds a set of blocks together.

Now each block that you see above has three elements that are the data, the hash and the hash from the previous block. Refer to the image below:

So, the code for every block is a combination of the hash of the current block, the hash of the previous block and a data code. This ensures that whenever someone tempers or even tries to temper with one block, all the following blocks making the chain will become invalid immediately. But this doesn’t mean that no changes can ever be updated in blockchain data. The only difference that lies here is the fact that whenever a user wishes to update any changes, the data entered by them will be added towards the end of the chain, more like our traditional ledger entry system that we studied back in school days.