Before, we have talked about how utxo solves the first kind of problem in the double spending problem, but there is another case of double spending problem, which is the double spending problem after bookkeeping. That is, although a sum of money is only used once, what if someone attacks the bank through hackers or uses counterfeiting methods to duplicate the money and use it again? In order to solve this problem, blockchain adds the concept of timestamp.
The so-called time stamp, according to the official definition, is a kind of data that can indicate that other data has completely existed before a certain time and can be verified. Generally, it is a character sequence that can uniquely identify the time of a certain moment.
There are two key points in this sentence. First, time stamp is also a kind of data. Second, time stamp can prove that some other data has existed completely at any time point. Therefore, in short, the timestamp is equivalent to the production date of the data, and plays the role of data verification.
Time stamp is closely related to Cryptography in blockchain. In fact, it can also be said to be an application of cryptography. Its working principle is as follows:
In the first step, the node will hash and encrypt the information in the block to generate an information digest, that is, the hash value.
Second, after the generation, the node will send a request for timestamp to the relevant timestamp server, and then the timestamp server will extract the hash value and the time information of the data.
The third step is that the timestamp server will sign the extracted hash value and time information, that is, encrypt again, stamp the time and generate the timestamp.
Finally, the generated timestamp data is bound with the transaction information and then returned to the system.
The whole process in the blockchain is that we first encrypt the data, then put it to another place for notarization, and take the secondary encryption as the proof. Then we put the proved things into the next block for packaging, and then repeatedly repeat such a process. Finally, we form a decentralization, and have experienced two times of hashing algorithm and timestamp Encrypted distributed system.
The advantage of this method is that it improves the tamperability of the blockchain, because every data is encrypted twice in the timestamp, and there are related time records. And when the blocks are connected, the time is sorted on the basis of hash algorithm. If someone wants to tamper with the data, not only to break the hash algorithm, but also to change the timestamp.
The reason why time stamp can solve the second kind of problem in Shuanghua is that it plays an anti-counterfeiting role. On the one hand, timestamps improve the security of the blockchain, and it is difficult for hackers to tamper with them. On the other hand, the system will automatically mark the transaction information of each block with a time stamp as a mark. You will have records of when and how much money you spent. If there is no such sign, it is “fake money”.
Generally speaking, time stamp plays a very important role in the blockchain. It allows each block to be nested layer by layer in chronological order, further enhancing the safety factor of the blockchain. It is precisely because of its existence that the problem of “fake money” in the blockchain is no longer a problem.
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