Browsing Tag: Oracle


    After the black swan, the DeFi data mutation!

    July 5, 2020

    On February 6, 2020, the total value of ETH and ERC-20 tokens locked in Ethereum’s DeFi ecosystem exceeded US $1 billion. After a series of high-level “smash” incidents, a series of “black swan” events coincide.

    bZx attack event

    In mid February 2020, two arbitrage “attacks” occurred in bZx protocol. After the event data statistics show that the two attacks before and after bZx protocol caused the total loss of 3649 ETH. Because Uniswap uses algorithmic price, the price is easy to change dramatically when the transaction depth is limited; arbitrage “attacker” just takes advantage of the algorithm price defect of Uniswap to manipulate the transaction price of some assets maliciously, which causes the users of the related DeFi protocol who introduce the Uniswap data as the Oracle price to suffer huge asset losses.

    ETH Locked in DeFi
    total value locked in DeFi

    After the bZx incident, from February 18 to February 19, the ETH lock up amount of Ethereum head DeFi protocol decreased by about 175000, about 5.8%; while the lock up amount of USD stable currency assets did not change significantly.

    The bZx protocol attack event led to a significant decrease in the number of ETH lockups, which indicates that a large number of DeFi users have doubts about the security of the DeFi protocol. At the same time, the bZx incident triggered a collective discussion on the issues related to the oracle and the flasloan in the industry.

    The encryption market plummeted on March 12

    At the end of the first quarter of 2020, the new crown epidemic is spreading rapidly around the world, which has a serious impact on almost all walks of life. The US stock market has experienced several historic fusions, and the crypto investment market is no exception. On March 12 (later known as “Black Thursday”), the U.S. stock market collapsed, and BTC, ETH and other mainstream encryption assets fell sharply by nearly 40% in a single day. According to the data, during the period from March 12 to March 13, all kinds of trading activities on Ethereum network increased significantly, resulting in serious network congestion for a long time, and many of the DeFi protocols had the highest active period in history.

    The market crash on March 12 affected almost all types of investment assets, including cryptocurrency, except for the stock market. Although the relationship between crypto investment market and traditional financial market does not always exist, the one-day crash and stock market crash are almost caused by the same reasons: the global panic and liquidity crisis caused by the new crown epidemic.

    Enlightenment from the collapse of encryption market on March 12: what is missing in DeFi?

    ETH locked in DeFi 2

    Based on the analysis of the data of online DeFi, we found that there was a large fluctuation in the amount of ETH lock positions from March 7 to 18

    3.07-3.10: ETH lock up volume increased from 2.893m to 3.03M, up 4.7%

    3.10 ~ 3.12: ETH lock up volume began to decline sharply, from 3.03M to 2.928 m, a decrease of 3.4%

    3.12-3.13: ETH lock up volume began to increase again, from 2.928m to 3.037m, up 3.7%

    3.13-3.18: ETH lock up volume began to decline all the way from 3.037m to 2.792m, a decrease of 8%

    This kind of volatility is the true reflection of Ethereum DeFi ecology in the case of a large drop in the price of ETH: at the beginning, the price of ETH fell slightly, the bondholders continued to make up their positions, and the amount of ETH locked positions increased; however, after the great fall of ETH price, some creditors did not have time to make up their positions, or gave up covering positions At the same time, there are also some debt holders who actively redeem the mortgage assets to avoid closing positions, which also makes ETH lock position decrease.

    From the above data performance, the instantaneous negative impact of 312 crash event on ETH lock up is less than the previous bZx attack event; however, as the price of ETH continues to fall, the impact of the event on the lock up of DeFi ecological ETH is growing: in the week after March 12, ETH lock up volume decreased by 12.2%.

    total value locked in DeFi 2

    On the other hand, on the day of 312 sharp fall, the scale of USD stable currency assets locked in DeFi declined significantly, from 893.43m on March 12 to 559.211m on March 13, and the 24-hour stable currency lock position decreased by more than 37%, which is also related to the “liquidity crisis” in the encryption market proposed by later industries.

    ERC777 protocol reentry attack

    On the morning of April 18, 2020, the Uniswap protocol was successfully attacked by hackers using the re-entry vulnerability. The hacker carried out this reentry attack through the compatibility defects of Uniswap and ERC777 standards, which exhausted about 1278 ETH assets in the Uniswap ETH-imBTC pool.

    What’s worse, just 24 hours later, at 08:45 a.m. on April 19, another DeFi protocol, dForce, was attacked by hackers in a similar way. In the dForce attack, hackers successfully borrowed a variety of encryption assets from dForce platform by using inflated imBTC as collateral, resulting in heavy losses to dForce platform users, with a total amount of up to 25 million US dollars. (Note: the stolen funds were recovered successfully under the coordination of various efforts)

    total value locked in DeFi 3
    ETH locked in DeFi 3
    total value locked in DeFi 4

    After the incident, the encryption funds of dForce lock warehouse dropped to nearly 0, and the head of the difi users suffered a serious impact, which greatly damaged the vitality of the whole industry. However, this re-entry attack is not a major technical vulnerability with high complexity, but a low-level development vulnerability, which does not have more impact on other Ethereum DeFi protocols. Therefore, from the data performance point of view, after the attack event, the lock up amount of ETH and USD stable currency assets of DeFi ecology did not fluctuate significantly.


    However, on the 19th, there was a huge increase in the related transactions of USD stable currency assets on Compund; in addition, the trading volume of USD stable currency on Kyber and IDEX also increased. Some of these data changes are closely related to the operation after hackers steal dForce assets.

    The incident of this reentry attack has triggered collective speculation in the DeFi industry, which is of great significance to the development of the entire DeFi industry. It makes more and more DFI developers begin to reexamine security issues, decentralization principles, rights and responsibilities involved, and even so-called moral issues.

    The above is about some accidents and data in the DeFi ecology since 2020.

    DeFi has just started, and it will be more wonderful next time. Let’s look forward to it!

    Logic and law

    Enlightenment from the collapse of encryption market on March 12: what is missing in DeFi?

    June 29, 2020

    The crash of March 12, and many people in the industry lost confidence, especially in the field of DeFi.

    Taking the stable currency project MakerDAO as an example, because of the collapse of 312, the debt position of the mortgage stable currency appeared to be out of position (i.e. insolvent), thus the MKR auction was started.

    In the whole process, various kinds of jokes were flying everywhere. Some said that the assets were captured at 0 cost, some said that the loss was how much, some said that the project was over, some wanted to sue them, and even the foundation felt pressure to hand over the governance to the community.

    Self-Sustaining MakerDAO

    It seems that the entire crypto community is beginning to doubt whether or not DeFi can really be established.

    This kind of doubt leads to collective reflection of the industry. Many people have written articles and summarized 312, with strange phenomena and even more strange explanations. MakerDAO has also made a lot of adjustments, including liquidation, auction and so on. It is becoming more and more complicated, but the purpose is only one, that is, when this situation occurs in the future, it can avoid the recurrence of 312 event. These starting points and original intentions are all good, and they hope that DeFi can have a virtuous cycle, sustainable development, and truly enter the public’s vision. However, these summaries, including the recent adjustment of MakerDAO, always feel that it is better to change the soup without changing the dressing, which does not point to the core of the problem.

    Currently, the well-known DeFi, whether MakerDAO or Compound, is the so-called excess mortgage and limit price closing mode. On the face of it, the excess mortgage and the liquidation of the water mark are impeccable. But these designs, in essence, are options one by one! Since it is an option, it must involve three important variables: price, risk-free rate of return and asset volatility.

    These things are not information on the chain. Because the impact of price variables is too significant, someone has designed a scheme called the Oracle, trying to transfer the required price from the centralized exchange representing price discovery.

    Both MakerDAO and Compound use price prediction machines. Then, the risk-free rate of return and volatility are implied in the pricing formula, which is not easy to detect. Therefore, no matter which DeFi is in the current market, the possible drastic fluctuations of these two are not considered in the design, and no in-depth sensitivity analysis is made.

    The risk-free rate of return is not mentioned first, because the impact factor of this variable is small and the frequency of significant changes is low. Next, let’s just talk about the volatility, which is a core variable that is generally missing in DeFi.


    Volatility measures the volatility level of return on assets. In finance, it is often measured by the standard deviation of return on assets in a given period (generally known as historical volatility, which is used to estimate the implied volatility).

    In option pricing, volatility is an indispensable and extremely sensitive variable, but this variable is dead written or adjusted by governance in current DeFi.

    Taking MakerDAO as an example, two important parameters ensure the stability of DAI: mortgage rate and position closing line (clearing line). However, these two parameters are not dynamically adjusted, that is, the contract is written at the beginning, for example, the mortgage is 50% off and the position is closed at 20%. If you want to adjust this indicator, you need the so-called chain governance, not automatic change of the system.

    Similarly, the same is true for us to borrow money from Compound. The mortgage rate and closing line are determined in advance and will not be automatically adjusted.

    However, under normal circumstances, the design of these two variables is reasonable. However, when the volatility rises sharply, it will present a very realistic challenge: sell out. Once you are out of position, you have to ensure the stability of DAI, which is impossible. The function of stabilizing currency will gradually lose efficacy. Since the fluctuation rate is not as obvious as the price change, and it is often relatively stable, these DeFis can operate stably and balance automatically in most cases. Even if Ethereum fell from $1400, MakerDAO would be able to circulate normally, and the mortgage scale would even continue to grow. Everyone felt that this reflected the greatness of decentralization.

    However, no matter how lucky you are, MakerDAO’s processing is ultimately missing one variable, and there is no feedback on volatility indicators.

    Volatility surged

    This kind of problem also exists in the AMM scheme that we will mention later.

    From a more abstract level, if there is less than one basic dimension variable, the participants can provide constrained information for the game. In the end, even if the equilibrium can be formed, it is also incomplete information equilibrium. Most of this kind of equilibrium is unstable: once it deviates from the track under some disturbances, it may never return, leading to the withdrawal of some participants and the end of the market.

    For example, in 312, MakerDAO was unable to deal with the sudden surge in volatility. The original position closing setting was broken by price fluctuation in a short period of time, resulting in some debt positions becoming insolvent. Due to this risk sharing mechanism, the intrinsic value of all DAI is devalued. In order to maintain the property of stable currency, MKR auction is adopted to restart manually, which is far from the spirit of DeFi. So later, the MakerDAO foundation also realized this problem. It did not want to and could not take responsibility, and gave the right of governance to the community.

    In fact, as a real DeFi protocol, it does not need to charge fees or governance rights. It is just a standard just like erc20 protocol. The premise is that the agreement should comprehensively reflect all variables of the service, instead of taking a model that is short of weight to deal with the complicated economic world.

    Logic and law

    Although we only cite the example of MakerDAO, the problems we reveal are universal. The absence of volatility makes all mortgage agreements go back to MakerDAO. This has nothing to do with luck. In the financial sector, we only believe in logic, not luck. Come out to mix, sooner or later is to return, today’s good luck, for tomorrow’s step on the pit buried foreshadowing.

    In the end, only logic and law can save you.