Blockchain software is used to create decentralized databases. It is completely "open source", which means that anyone can view, edit, and propose changes to the underlying codebase. It has been popularized by Bitcoin's growth, but it is actually around a decade old.
Blockchain technology fiirms created this to allow applications to be developed without the need for a central data processing server. If you use a system built on it (such as Bitcoin), your data will be stored on thousands of "independent" servers all over the globe (not owned or controlled by any central service).
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This service works by creating a "ledger". This ledger allows users to create transactions with one another. The contents of these transactions are stored in "blocks" within each "blockchain" database. Different algorithms should be used depending on which application is creating the transactions.
This encryption uses cryptography to "scramble” the data in each "block", so the term "crypto” refers to the process of cryptographically protecting any new blockchain data an application creates. It is important to understand that "blockchain" uses technology in a different way. It all revolves around a data graph called "merkle trees". Merkle trees allow computer systems to keep chronologically-ordered "versions" of a data set, which allows them to manage continuous upgrades.