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As the number of cryptocurrencies has exploded in recent years, so too has the fraud. One popular strategy is when actors promote coordinated purchases of coins in hopes of temporarily driving up prices. Prior work investigating such pump and dump schemes has focused on the immediate impact to prices following pump signals, which were largely interpreted as following the same strategy. The reality, as with most cybercrimes, is that the operators of the schemes try out a much more heterogeneous mix of tactics. From a population of 12,252 pump signals observed between July 2017 and January 2019, we identify and examine 3,683 so-called target-based pump signals that announce promoted coins alongside buy and sell targets, but without a coordinated purchase time. We develop a strategy to measure the success of target pumps over longer time horizons. We find that around half of these pumps reach at least one of their sell targets, and that reaching their peak price often takes days, as opposed to the seconds or minutes required in pumps studied previously. We also examine the various groups promoting coins and present evidence that groups try a variety of distinct strategies and experience varying success. We find that the most successful groups promote many coins and issue many pumps, but not for the same coins. As decentralized finance becomes more popular, a deeper understanding of price manipulation techniques like target pumps is needed to combat fraud. 

Since Bitcoin’s introduction in 2009, interest in cryptocurrencies has soared. One manifestation of this interest has been the explosion of newly created coins and tokens. In this paper, we analyze the dynamics of this burgeoning industry. We consider both cryptocurrency coins and tokens. The paper examines the dynamics of coin and token creation, competition and destruction in the cryptocurrency industry. In order to conduct the analysis, we develop a methodology to identify peaks in prices and trade volume, as well as when coins and tokens are abandoned and subsequently “resurrected”. We also study trading activity. Our data spans more than 4 years: there are 1082 coins and 725 tokens in the data. While there are some similarities between coins and tokens regarding dynamics, there are some striking differences as well. Overall, we find that 44% of publicly-traded coins are abandoned, at least temporarily. 71% of abandoned coins are later resurrected, leaving 18% of coins to fail permanently. Tokens experience abandonment less frequently, with only 7% abandonment and 5% permanent token abandonment at the end of the data. Using linear regressions, we find that market variables such as the bitcoin price are not associated with the rate of introducing new coins, though they are positively associated with issuing new tokens. We find that for both coins and tokens, market variables are positively associated with resurrection. We then examine the effect that the bursting of the Bitcoin bubble in December 2017 had on the dynamics in the industry. Unlike the end of the 2013 bubble, some alternative cryptocurrencies continue to flourish after the bursting of this bubble. 

Thousands of new cryptocurrencies have been introduced in recent years. Most are introduced with a so-called "whitepaper" containing a mix of technical documentation, legal boilerplate and marketing material. Notably, many proposed currencies reuse text from previous established cryptocurrencies. We analyze the whitepapers from 1 260 actively traded cryptocurrencies and 2 039 ICOs. We develop two measures of similarity. Moderately similar papers reuse text in a portion of the paper, often the legal disclaimers. By contrast, some highly similar whitepapers appear to copy most of the text. 4% of coin and 19% of ICO whitepapers are highly similar to those of traded coins. The fraction rises to 64% for coins and 67% for ICOs when we consider moderate text reuse. 

Interest in cryptocurrencies has surged in recent years. Today thousands of currencies are in circulation, collectively worth hundreds of billions of dollars. Software vulnerabilities have also proliferated, which poses new and unique challenges to the ecosystem as it has developed. This review article explains what is different about vulnerabilities and responsible disclosure in cryptocurrencies, identifying key problems and opportunities for research and development. Selected case studies of vulnerability disclosures are presented. We draw lessons and pose open questions that can inform the responsible disclosure debate in cryptocurrencies and beyond. 

The surge of interest in cryptocurrencies has been accompanied by a proliferation of fraud. This paper examines pump and dump schemes. The recent explosion of nearly 2,000 cryptocurrencies in an unregulated environment has expanded the scope for abuse. We quantify the scope of cryptocurrency pump and dump on Discord and Telegram, two popular group-messaging platforms.We joined all relevant Telegram and Discord groups/channels and identifiednearly 5,000 different pumps. Our findings provide the first measure of the scope of pumps and suggest that this phenomenon is widespread and prices often rise significantly. We also examine which factors affect the pump’s “success". 

Since Bitcoin’s introduction in 2009, interest in cryptocurrencies has soared. One manifestation of this interest has been the explosion of newly created coins. This paper examines the dynamics of coin creation, competition and destruction in the cryptocurrency industry. In order to conduct the analysis, we develop a methodology to identify peaks in prices and trade volume, as well as when coins are abandoned and subsequently “resurrected”. We study trading activity associated with 1 082 coins over a nearly five-year period. We present evidence that the more frequently traded coins experience the biggest price rises. They are also much less likely to be abandoned, that is, to experience a drop in average trading volume to below 1% of a prior peak value. Overall, we find that 44% of publicly-traded coins are abandoned, at least temporarily. 71% of abandoned coins are later resurrected, leaving 18% of coins to fail permanently. We then examine the association between entry and exit and other key variables such as price, volume, and market capitalization in order to analyze and provide intuition underpinning the fundamentals in this market. We conclude by examining the bursting of the Bitcoin bubble in December 2017. Unlike the end of the 2013 bubble, some alternative cryptocurrencies continue to flourish after the fall of Bitcoin.