In simple terms block chain is simply a block of chains which contain information. It was originally in 1991designed to be a digital timestamp for documents so as not to backdate them or tamper with them but it was largely unused till it was adopted by Sakoshi Nakomoto in 2009 the creator of bitcoin.
A blockchain is simply a distributed ledger which means it is open for anyone. Once a data has been recorded in the blockchain it becomes difficult to change it. A block contains data, hash of the data and hash of the previous block. Hash is the digital footprint of a digital data thus immutable to hack. In essence a bitcoin blockchain stores the data of A sending bitcoin to B and the hash is the unique identifier of that transaction thus when you send bitcoin from A to B you have essentially created a new block in the blockchain, the hash of the previous block link the new block to each other, the hash is supposed to protect the integrity of the blocks in the chain thus if you tamper with the hash of block 2 then automatically it renders the rest of the block in the blockchain invalid, to guard against this bitcoin came up with Proof of Work which means the blockchain takes about 10 minutes to verify a transaction. Essentially the proof of work checks the integrity of other blocks in the chain before verifying the transaction and also by so doing to protect itself more bitcoin uses a P2P network which anybody is allowed to join and once you join the network you are allowed to view the entire blockchain and when you are about to create a block it is sent to everyone on the P2P network via what is called a Node, everyone on the P2P network will verify it has not been tampered with and thus verify the transaction, this verification is what is called a Consensus. Any block that has been tampered with will be rejected by the nodes in the network therefore to tamper with any block you have to undo the hash of each block and redo the proof of work of all the blocks in the blockchain and also take control of 50% of the P2P network only then will your tampered block be accepted by the network therefore it is almost impossible to tamper with the block chain
Also, blockchains are constantly evolving which has now brought about the creation of what we call a Smart Contracts, they are simple programs stored on the blockchain to automatically exchange coins based on certain conditions which we will delve into in the next lesson.
Blockchain is the technology behind Bitcoin which is the first decentralized digital currency, it is created and held electronically in a peer-to-peer open distributed ledger called the blockchain.
Ledger is produced by the people using software that solves mathematical problems. Every block is anonymous
Each block is validated by miners before approving the transactions. This takes place in real time. Miners get an incentive of 12.5BTC for every bitcoin validated. A block is created every ten minutes
A lot of miners come together to form a pool to mine a bitcoin.
A block is the current part of a blockchain which records some or all of the recent transactions and once completed goes into the blockchain as permanent database. Each time a block gets completed a new block is generated.
Blockchain solves peer to peer transaction by doing the below
Someone requests a transaction —- it goes into the Peer-to-peer network —– it is then validated —– a new blockchain is created and added — and the transaction is complete
Basically, Blockchain is a public distributed database holding encrypted ledgers. Blockchain is the use of mathematics to secure a distributed ledger which enables transactions without the use for third parties.