Understanding Blocks

Blocks are where transaction data is stored in a blockchain. Each block has a hash and, as described here, that hash uniquely identifies the information contained within the block.

Blocks are created by miners (or validators in Proof of Stake) and contain recent transactions. When a valid block is produced, it is propagated throughout the network and each miner adds the block to their copy of the blockchain.

The table below shows the information contained within a block

Table provided by Bitcoin Wiki

The two main pieces here are the transactions and the blockheader. The transactions contain inputs and outputs as well as the digital signature of the sender.

The blockheader contains several pieces including the nonce (a somewhat random number), timestamp, the hash of the transactions in the block, and the hash of the previous block.

From Blocks to Blockchain

Individual blocks are linked together to make the blockchain. The blocks are linked by the hash of the previous block. This linkage (and the concept of hashes) makes it very easy to detect if someone has changed their copy of the blockchain. Take a look at the visuals below.

Source: Blockchain Demo

In the two blocks above there is transaction data, a nonce, the hash of the previous block, and the hash of the current block. This is a simplified model but serves the purpose of visualizing blocks.

Notice how the hash of block 1 (ending in d64) is used as an input in block 2. This means that the hash of block 2 is partially determined by the hash the previous block.

If someone were to change the transactions in block 1, the hash of block 1 would change. That would then cause the hash of block 2 to change.

Source: Blockchain Demo

In this second visual, the first transaction in block 1 has been changed. The hash of block 1 changes because of this.

Compare the hashes of block 2 from both visuals. They are different because the hash of block 1 changed.

This feature allows for easy checking of different copies of the blockchain and allows people (and computers) to come to a consensus on the ‘real’ version of the blockchain.


Sign up for our newsletter to receive recent news & updates, and follow us on social media:

Website | Twitter | Linkedin | Facebook | Telegram


Legal: legal@stably.io

Press: marketing@stably.io

Exchanges or Market Makers: exchanges@stably.io

Partnerships: info@stably.io

Investors: Kory Hoang, CEO — kory@stably.io

Stably is the creator of Stably USD, a USD-backed stablecoin and Stably Prime, a borderless account with a multitude of financial services and products, customizable to the individual or institutions specific needs.

All asset custody, funds processing, convertible virtual currency administration, trustee and fiduciary services are provided by Prime Trust, a Nevada chartered financial institution and licensed trust company. Digital assets are held in secure cold storage and USD funds are held in FDIC-insured bank accounts by Prime Trust. Stably is not a licensed financial institution and Stably does not manage nor take custody of client funds. Prime Trust neither endorses nor guarantees any of the information, recommendations, optional programs, products, or services advertised, offered by, or made available through the external website ("Products and Services") and disclaims any liability for any failure of the Products and Services.

Please note: By clicking on some of the links above, you will leave the Stably website and be directed to an external website. The privacy policies of the external website may differ from our privacy policies. Please review the privacy policies and security indicators displayed on the external website before providing any personal information.

Copyright © 2019-2020 Stably Corporation. All Rights Reserved