What is a blockchain?



To put it simply, the technology that is a 'transaction ledger that is resistant to data alteration' is '

blockchain .' The Verge, an overseas media, explains the blockchain that has become widely known due to the advent of crypto assets.

Blockchain, explained: what's a block, what's a chain, and the tech behind crypto --The Verge
https://www.theverge.com/22654785/blockchain-explained-cryptocurrency-what-is-stake-nft

A blockchain 'block' is a 'record' of digital information. In the case of crypto assets, 'who sent money to whom' and 'what and how much money was sent' correspond to 'records'. Every time a new record (block) is created, it is added to the previous record one after another, so a time series information that describes a series of records is completed. This is the 'blockchain'.

Since this blockchain cannot modify or delete records along the way, you can always check 'what, how much, and to whom' as reliable information. In addition, since anyone can create a new blockchain, it has the potential to be used in all fields, not just crypto assets.



When someone creates a blockchain, the creator first creates what is called a

genesis block. A Genesis block is an empty block that does not hit the record and points to nothing. You can use it for new crypto assets, track the lettuce you grow, or whatever you like.

In the blockchain, records are communicated and shared via networked personal computers. In addition to maintaining records, each computer, called a node, is responsible for checking the records for tampering. When someone creates a new block, it takes the form of adding the block to the network after verifying that the node other than the creator is a valid block.

To understand how a node checks for tampering, we need to understand 'hashes'. In the blockchain, a hash is a specific string that distinguishes each piece of data. Each block has a specific hash embedded in it, and when a new block is added to a block, the hash of the previous block is read and recorded in its own block.



When someone tries to add a new block, it checks to see if this hash is the same as what is recorded on the legitimate blockchain. A legitimate blockchain is the blockchain with the most transactions, and in crypto assets it is the 'chain with the most blocks'.

The correctness of the hash is confirmed using an algorithm. For example, suppose you enter 'blockchain' in the hash generation algorithm to generate the string 'ef7797', and enter one character different 'blockchain' to generate the string '8e809e'. At this time, anyone can generate the character string 'ef7797' from the character string 'blockchain', but on the contrary, the character string 'blockchain' is reverse-looked up from the character string 'ef7797'. It's very difficult to do.

In addition, each block contains a hash of the previous block, and if the block is modified, the block chain, that is, the block chain will be broken. Therefore, if you check the newly added block to the chain, you can see that the previous transactions including that block have not been modified. Cryptography is used to generate the hash used by the blockchain. This is one of the origins of Bitcoin using blockchain, which is called a crypto asset.



Although the blockchain contains all transaction records, it does not contain any personal information such as name or address. In addition to the transaction record mentioned above, the only information that exists instead is a unique character string. The string indicates 'someone specific', but it is impossible to identify who it is.

The Verge pointed out that 'blockchain only means that the record is accurate.' For example, suppose someone sells just a pebble as a 'moon rock' and tracks the record on the blockchain. Even if the pebbles fall into the hands of different people, the blockchain only proves that the transaction record is accurate, not that it is a real moon rock.

'Blockchain can be used in a variety of areas, such as election voting,' said The Verge, but 'I don't know if it will be accepted by people.'

in Posted by log1p_kr