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Snarks drew attention to time.

In the cryptocurrency world, anonymous currency is a kind of currency that is rarely mentioned. Recently, however, Korbit, the Korean exchange, took the lead in removing three anonymous coins, namely DASH, Monero and Zcash, and Coincheck in Japan was also implemented simultaneously. Why?

First of all, we need to know the difference between "anonymous currency" and "cryptocurrency".

The difference between general cryptocurrency and anonymous currency cryptocurrency has several important definitions, such as "distributed system", "invariance" and "anonymity".

Distributed system: refers to the fact that the database exists in every corner of the world, and the data will not be lost because of the damage of a centralized database. Invariance: It means that the record after the transaction cannot be tampered with, which is related to the unique knowledge mechanism of the system itself. Anonymity: the two parties representing the transaction cannot be directly identified. The author also roughly divides cryptocurrencies into "general cryptocurrencies" and "anonymous currencies", as follows:

The so-called "anonymity" is literally and intuitively interpreted as "no real name or anonymity". The former usually has another name or code name, while the latter has no information. Similarly, in the cryptocurrency world, according to the degree of anonymity (anonymity), currency can be divided into "general cryptocurrency" and "anonymous currency":

No real name is used in the transaction, that is, no name is used in the transaction of "universal cryptocurrency", which is the first way of "anonymous currency", that is, the so-called "semi-anonymity", which is called "pseudo" in English.

The second way, "anonymity", is "anonymity" in English.

In order to explain the first way "semi-anonymity", we take the most representative "bitcoin" as an example:

The origin of Bitcoin comes from Satoshi Nakamoto's paper. In this paper, the concept of bookkeeping appears in the records of the whole blockchain. In the vernacular, in the transaction behavior of Bitcoin, except the real name of the trader, all other information is public, and anyone can trace its transaction records, such as transaction amount, transaction time and so on. It's like you have your own account on PTT and Dcard. Villagers can find out whether this person is used on campus through IP location, but no one knows what the person behind the account looks like.

Similarly, the "semi-anonymity" feature of "Bitcoin" is like knowing how much money is in the nearby house (wallet address), which wallets are being traded, the transaction amount, the number of transactions and other information, but not knowing who the owner (owner) is. And according to this feature, we can infer the general outline of the wallet owner. Such a "semi-anonymous" feature, once some information is mastered by others, there is a chance to find the owner of the wallet through relevant clues.

It is this "semi-anonymity" feature that makes it possible for * * to supervise "universal cryptocurrency". Therefore, when a user wants to register and use a cryptocurrency exchange, the relevant account must be authenticated by KYC(knowyourcuster).

The advantage of "semi-anonymity" is that the transaction records are public, and the security and fairness of the transaction are completed by "miners", so both parties must not have any objections. If there is no clue to link the wallet address with the real identity of the user, then "anonymity" is no problem. However, everyone can find the address of your wallet, which is equivalent to having the opportunity to identify your actual wealth. Once the association between your wallet and the user is identified, there will be many security problems in real life. Imagine, in daily life, do you want every transaction to be known by relatives and friends? Think about asking your parents to check with him after shopping with their credit cards!

Therefore, the anonymity of cryptocurrencies such as "Bitcoin" only exists when your wallet address is not known by a third party and has never been linked to legal tender. As long as we know the wallet address, with the help of KYC, there is a way to find the user himself.

Is that really the case? Let's look at an example of blockchain transaction records:

1. The author randomly found a wallet address "1mlxsrapbsfehx8pcimjgwwwygwfpz".

2. Check this wallet on the blockchain.

The blockchain revealed some information. For example, there are five transactions in this wallet, and there are currently 0.788 1 bitcoin, with a total of 29.845438+0 1 bitcoin. According to the transaction records, this wallet first appeared in 2018/014, and was remitted by the wallet of "17msc2vy5we lpx3r8stnmz2bhw6nhm", indicating that there must be some connection between the two wallets. block chain . info/address/ 1 mlxrapbsfehx 8 pcim jgwwwygwfpz 3。 Found the transaction record of this wallet.

This user paid the wallet "14mnaauqyldvxzmurmb75 rhkanutvvts 7" three times, and spent about 28 bitcoins. 4. Interested people can infer the real identity of this wallet user through relevant information.

When you have such a transaction record, plus the KYC promoted by the international anti-money laundering law, you can implement various follow-up actions; For example, "tax". Similarly, the transaction records of digital currency such as "Ethereum" and "Litecoin" are equally transparent. It's really meaningless to use this easily traceable digital currency for various underground economic operations.

Some people think that when the original wallet address and personal information are exposed, it is enough to change a wallet (that is, wallet address), but in fact, if there is a capital conversion between the old and new wallets, the information will also exist in the blockchain and will be traced back. Therefore, even if you have multiple wallets, you must ensure that there is no transaction between wallets, otherwise you will define the association. Besides, managing multiple wallets, the cost of bookkeeping is actually quite high.

Off-topic, cryptocurrency transactions can be completed through various cryptocurrencies or legal tender. If you trade in legal tender, you will enter the financial system controlled by * * *. So I heard that some people do not want to trade through cryptocurrency service providers in order to counter-trace (to avoid taxes or reduce the price difference), but take offline delivery and other ways. But this is actually very dangerous. Not only can it be traced back when it is cheated, but there may also be personal safety problems. Imagine the plot of black market trading in the movie, giving money while delivering goods, and it is a lot of money. Without the protection of a third party, if one party is cheated, it may just take the money and run away, but once there is a conflict, the two sides will start to fight! Wow, this is too * * *.

Back to the topic, the anonymity of Bitcoin is not strong enough, and anonymous "anonymous coins" have real application scenarios and needs.

Taking the transaction between companies as an analogy, the "universal cryptocurrency" can be clearly seen, which is all the transaction information between companies. Imagine how much impact it will have on the company itself and the "stock market" after the transaction records of each order between Hon Hai and its suppliers are made public. Let's look at "anonymous coins". It's like hearing that there are transactions between large and small enterprises in the technology industry every minute, but you can't see the company name, transaction amount, transaction time and so on. As a third party, you can only see some irrelevant certification records.

It can be seen that anonymous coins hide the characteristics of "wallet address" and "transaction amount", which not only meets the general needs, but also meets the needs of the underground economy, because no one can know the details except the two parties to the transaction. This is the main reason why anonymous coins will be singled out.

As for "anonymous coins", is it as magical as the above? Let's take Monerau's Blockchain as an example:

1. Select any blockchain transaction record.

The public information of blockchain is only "format block", "cost", "size" and "mixed". If you don't have the golden spoon of PaymentID, you can't see anything at all. 2. I can't know the transaction amount and wallet address.

The total transaction amount of input and output is shown as 0, and outsiders can't know anything. Based on the above demand motives for using "anonymous coins":

We need to reach the level of privacy protection provided by the current banking system and reduce the risks brought by information leakage. Need to go beyond the level of privacy protection brought by the existing financial system. However, the motivation of using anonymous coins is a very difficult thing to deal with from the perspective of * * * supervision. The author believes that this is the reason why anonymous coins are required to be removed from the shelf. Because there is no way to control them, they can only reduce their mobility.

There are too many parts to learn after anonymous coins. Interested readers can go to the author's blog "Lin Puppy Lab" to do more study and research with the author. If you don't know about cryptocurrency, you can read the series of articles on "digital currency Lazy Bag" or leave your information for subsequent update.

The author sorts out several commonly used methods to improve "anonymity" for readers' further inquiry.

StealthaddressesMix (mixed currency) RingCT (ring signature) Successful non-interactive demonstration without knowledge proof (ZK- Snak) Tor There are still many topics to be discussed in the future. The author lists a few topics first, and interested readers can leave me a message.

The difference between anonymous coins in anonymity: the methodology of privacy protection technology What anonymous coins exist in the world now? Are there miners in anonymous coins?