

BLOCK BLOCK BLOCKBLOCK VERIFICATION
Since each of these transactions contains the verifiable signature of the public address from which it was generated, the possibility of public verification of the correctness of both the block and all the transactions inserted in it makes the blockchain a ledger of very high reliability. Thus, the mining of a block also means, in addition to the validation of the block itself, the confirmation of the validity of all the transactions contained in it. with a correct and verifiable hash, and with the hash of the previous block inside it. In order to be considered valid, a blockchain transaction must be included in a mined block, i.e. So what do the data packages of the blocks contain besides the hash of the previous block? They contain transactions. To be clear: the activity of validating blocks by calculating the hash is called mining. This means that if someone wanted to change a block, they would have to change all the following blocks and calculate the hash.Ĭalculating the hash is a very expensive task, so it is not convenient to try to edit blocks already confirmed with the hash. It is enough to change even a single piece of data for the hash to change, so once a block with a hash is created, it cannot be changed anymore (otherwise its hash would be incorrect). Moreover, these blocks are concatenated because the data package of each block includes the hash of the previous block.
BLOCK BLOCK BLOCKBLOCK DOWNLOAD
Indeed, once this hash is found, the block is added to the blockchain and since they are all public data, anyone can download the data packet included in the block and verify the correctness of the hash. On the bitcoin blockchain, for example, more than 630,000 blocks have been mined in just over 11 years.īlocks are data packets marked with a specific code, called a hash, which allows anyone to verify their authenticity. The blockchain, as the word suggests, is a chain of blocks, but what does the block in the blockchain consist of?
