What is a block? The DNA of every blockchain transaction

Although blockchains such as Bitcoin popularised the notion of blocks, their impact is felt much further than online currencies. They support distributed ledgers running supply chains, medical data, digital identity and others. The core structure of a block is a digital container that stores a group of verified transactions. Each block is made up of two significant components, the body and the header. Each header has metadata that ensures the status of the block on the chain - which can be a time stamp, a unique cryptographic hash and the hash of the previous block. These factors make all blocks verifiable and linked to their predecessor in time sequence. The body of the block contains the data of the actual transaction - in cryptocurrency networks, this usually includes address of sender and receiver, the amount to be transferred and the cryptographic signatures. In other applications, there may be supply chain updates, medical records or IoT-based entries in the body. The design gua…