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This article mainly explains "how the block chain can not be tampered with", interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Next let the editor to take you to learn "how to block chain can not be tampered with" it!

1. The transaction cannot be tampered with.

When we send a transaction to the block chain node, the node will verify the signature of the transaction. If the signature is incorrect, the data will be discarded. Only the person with the private key can modify the transaction, and no one else can modify it. This problem is solved by cryptography. In Bitcoin, the elliptic curve algorithm is used to sign the transaction.

The modification of any transaction will lead to the change of the block.

two。 Block can not be tampered with.

There is a transaction in the block, which is organized by the Merkel tree, and if any of these transactions is modified, it will cause a change in the root hash of the Merkel tree, which is solved by the hash function. The sha256 algorithm is used in Bitcoin

The change of block will lead to the change of block.

3. The block size cannot be tampered with.

The first two problems are guaranteed by unsolvable mathematical problems, and the unmodifiability of blocks is guaranteed by arithmetic, which is what miners need to do. So how does the block make sure it can't be modified?

All miners around the world calculate the hash of the block, but the calculated hash requires n zeros in front of it. If the header information of the block remains the same, then the calculated hash is the same. As we said earlier, the block contains a nonce, and the foreign exchange www.gendan5.com miners modify the nonce to find the hash that meets the requirements (a process known as mining). In the Bitcoin world, this problem takes about ten minutes for miners around the world to find a nonce that meets the requirements. So it is completely impossible for an individual to modify a block.

Once the miners have calculated the nonce, they will broadcast the block to other nodes, which will verify the data in the block. If the verification is passed, they will stop the mining of this block, broadcast the block to other nodes, and begin to compete for the accounting rights of the next block.

The change of block head will lead to the change of block chain.

Block chains are linked sequentially from zero, and each block points to the previous block, which is called the child block of the previous block, and the previous block is called the parent block.

Each block has a block head that contains the hash value generated by the algorithm of the parent block, through which the parent block can be found. When there is any change in the parent block, the hash value of the parent block also changes. This will force the hash field of the sub-block to change, and so on, the subsequent sub-blocks, sub-blocks will be affected. Once a block has many descendants, unless the blocks of all descendants of the block are recalculated, but this recalculation requires a huge amount of computation, so the longer the block chain, the more unable to change the block history.

Since there is exactly the same ledger, it means that all the data are open and transparent, and everyone can see what numerical changes have taken place in each account.

Its interesting feature is that the data in it cannot be tampered with. Because the system will automatically compare, it will think that the same number of books with the largest number of books are real books, and a small number of books that are different from others are false books.

In this case, it doesn't make sense for anyone to tamper with their own books, because unless you can tamper with most of the nodes in the system.

If there are only five or ten nodes in the whole system, it may be easy to do it, but if there are tens of thousands or even hundreds of thousands of nodes, and they are still distributed anywhere on the Internet, unless someone can control most of the computers in the world, otherwise it is unlikely to tamper with such a large block chain.

At this point, I believe that everyone has a deeper understanding of "block chain how can not be tampered with", might as well come to the actual operation of it! Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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