What is blockchain?

The goal with this blog post it to explain what blockchain is without using a very technical description and lots of abbreviations and difficult terms.

There are quite a lot of different definitions of what blockchain is:
Wikepedia explains it with this definition:

blockchain is a growing list of records, called blocks, that are linked together using cryptography.[1][2][3][4] Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data (generally represented as a Merkle tree). The timestamp proves that the transaction data existed when the block was published in order to get into its hash. As blocks each contain information about the block previous to it, they form a chain, with each additional block reinforcing the ones before it. Therefore, blockchains are resistant to modification of their data because once recorded, the data in any given block cannot be altered retroactively without altering all subsequent blocks.


From this definition we learn that it is a list of records known as blocks that are linked together, each block contain information about the block previous to it and therefore they form a chain and this is where we get the name Blockchain. They also go on and describe how this chain between all the blocks means that the blocks can not be altered afterwards, making it very secure since it can not be modified without it being recorded.

Bankrate.com describes it as following:

A blockchain is a digital, public ledger that records online transactions. Blockchain is the core technology for cryptocurrencies like bitcoin. A blockchain ensures the integrity of a cryptocurrency by encrypting, validating, and permanently recording transactions. A blockchain is similar to a bank’s ledger, but open and accessible to everyone who utilizes the cryptocurrency is supports.


Here another common term for describing Blockchain is introduced and that is ledger. A ledger is a term most commonly used within accounting and means a collection of accounts. Here it´s also explained that Blockchain is the technology used to create cryptocurrency.

IBM describes it as following:

Blockchain defined: Blockchain is a shared, immutable ledger that facilitates the process of recording transactions and tracking assets in a business network. An asset can be tangible (a house, car, cash, land) or intangible (intellectual property, patents, copyrights, branding). Virtually anything of value can be tracked and traded on a blockchain network, reducing risk and cutting costs for all involved.


Okay, so let´s try to make sense of these different definitions and understandings of blockchain. First of all the proper way to spell blockchain is with lowercased letters (unless it´s used in a title).

Blockchain is a shared ledger used to permanently store transactions for different assets (for example currency, an object or pretty much anything you like). Since the data is stored on a shared ledger that is split into lots of different nodes makes it impossible (or at least extremely hard) to make any illicit changes.

I hope this clarifies and explains it a bit more, I´m now going to look into how the blockchain technology is utilized.