Unlike banking transactions, bitcoin transactions are digitally signed and irreversible, and are stored in a network of peer-to-peer nodes (running Bitcoin Core) using the Bitcoin protocol (Antonopoulos, 201.Blockchain is decentralized and therefore there is no central place to store it ). That's why it's stored on computers or systems across the network. These systems or computers are known as nodes. Each of the nodes has a copy of the blockchain or, in other words, the transactions that take place on the network.
How are data (immutable blocks) stored in the general ledger of all the complete nodes of a Blockchain? is in memory, in a file (such as a JSON, CSV file) or in DB Blockchain is a distributed database. This means that the data is scattered across the nodes (participating computers). Each node can decide how to store the data (and if it will store it). When data is accessed, messages are sent to network nodes.
In principle, you don't have to store any part of the blockchain on your computer if you just want to send transactions. Blockchain protocol ensures that it can reconstruct data from bits of information received correctly and reliably. Bitcoin works with an unprecedented level of transparency that most people aren't used to dealing with. All Bitcoin transactions are public, traceable and permanently stored on the Bitcoin network.
Bitcoin addresses are the only information used to define where bitcoins are allocated and where are sent. These addresses are created privately in each user's wallets. However, once the addresses are used, they are affected by the history of all the transactions in which they are involved. Anyone can view the balance and all transactions from any address.
Because users often have to reveal their identity to receive services or goods, Bitcoin addresses cannot remain completely anonymous. Since blockchain is permanent, it's important to keep in mind that something that can't currently be traced may turn into something trivial to track in the future. For these reasons, Bitcoin addresses should only be used once and users should be careful not to reveal their addresses. Bitcoin was created to work as peer-to-peer electronic money.
Whether you're spending or accepting bitcoin as payment, it's wise to understand how a transaction works. Bitcoin transactions are messages, such as email, that are digitally signed using cryptography and sent to the entire Bitcoin network for verification. Transaction information is public and can be found in the digital ledger known as the “blockchain”. Each owner transfers bitcoins to the next one by digitally signing a hash of the previous transaction and the public key of the next owner and adding them to the end of the coin.
Blockchains are best known for their crucial role in cryptocurrency systems, such as Bitcoin, to maintain a secure and decentralized record of transactions. The keys to a bitcoin wallet can be stored on a piece of paper, a cheap mobile phone, or even memorized if necessary. Bitcoin network participants (nodes) update these transaction logs and share them on each of their nodes as balances increase or decrease. In a research paper introducing digital currency, Bitcoin's pseudonymous creator, Satoshi Nakamoto, referred to it as “a new electronic cash system that is totally peer-to-peer, with no trusted third parties.
Unless your intention is to receive public donations or payments with complete transparency, posting a Bitcoin address in any public space, such as a website or social network, is not a good idea when it comes to privacy. With many practical applications for the technology already being implemented and explored, blockchain is finally making a name for itself largely due to bitcoin and cryptocurrency. But recent work by Sirer and colleagues shows that neither Bitcoin nor Ethereum is as decentralized as you might think. While it is becoming increasingly difficult and almost impossible to put an end to something like Bitcoin as its decentralized network grows, governments could, in theory, make it illegal to own cryptocurrencies or participate in their networks.
For large blockchains, such as Ethereum and Bitcoin, all blockchain data is on the order of hundreds of gigabytes, so if you configure your software to store them locally, the software will typically download several large files from other computers and store them on your disk. This is because when miners add a block to the bitcoin blockchain, they are rewarded with enough bitcoin to make their time and energy worthwhile. To send Bitcoin, you must have access to the public and private keys associated with the amount of bitcoins you want to send. You can use a “block explorer” if you want to see the history, as well as the current balance, of any given Bitcoin address.