With evolutionary roots in the 1990s and its second-hand marketing propagated by cryptocurrencies, blockchain technology has risen to the forefront of security, record-keeping and related fields.
What it actually is
A blockchain is a block of transactional records held together in a chain by interconnected links of cryptographic keys. What makes blockchains distinctively secure is the uniqueness of the cryptographic keys of each block. The chain is distributed to multiple computers for a decentralized system of record-keeping.
Any tampering with the data of a block changes the hash of that block, and hence of the block after it, leaving inconsistencies between different versions of the same chain.
The keys, called hashes, of each block are cryptographically generated based on the data the block and its predecessor possess. That is the whole mechanism: not that records cannot be altered, but that altering one is immediately visible everywhere the chain is held.
Where it is being applied
Healthcare
Patient records and other medical information can be securely consulted or transferred across institutions without risk of tampering, which adds security for patients needing international healthcare.
Banking and finance
Many institutions employ blockchain to reduce intermediaries in bank operations and improve transparency and accountability in public transactions. Decentralized record-keeping also helps avoid targeted attacks on central servers.
Public voting
Modern electronic voting machines and ballot systems remain vulnerable to remote attack. Decentralized data management makes a targeted attack on the voter count far harder.
Cryptocurrency
Currencies like Bitcoin and Ethereum are modelled around the transparent and decentralized transactional systems of blockchains, which makes payments accountable while retaining user privacy.
Supply chain
Platforms help businesses monitor shipped goods, delivery dates, driver tracking, materials supply and payments through a system of accountability that lets logistics operations be backtracked.
Internet of Things
Connectivity presents more opportunities for attackers to reach your data through IoT devices. Enabling blockchain security within those devices adds a layer to personal data protection.
The demand behind it
A survey around the time of writing found over 70% of companies already employ or aim to integrate blockchain technology within the next year, and the decade before saw over a 500% rise in demand for software engineers specializing in it. Growing connectivity has raised questions about proper data handling, public data security, accountability in transactions, and whether a centralized system is ideal for data security at all.