Abstract: The cryptocurrency is attracting more and more attention because of the blockchain technology. Ethereum is gaining a significant popularity in blockchain community, mainly due to the fact that it is designed in a way that enables developers to write smart contracts and decentralized applications (Dapps). There are many kinds of cryptocurrency information on the social network. The risks and fraud problems behind it have pushed many countries including the United States, South Korea, and China to make warnings and set up corresponding regulations. However, the security of Ethereum smart contracts has not gained much attention. Through the Deep Learning approach, we propose a method of sentiment analysis for Ethereum's community comments. In this research, we first collected the users' cryptocurrency comments from the social network and then fed to our LSTM + CNN model for training. Then we made prediction through sentiment analysis. With our research result, we have demonstrated that both the precision and the recall of sentiment analysis can achieve 0.80+. More importantly, we deploy our sentiment analysis1 on RatingToken and Coin Master (mobile application of Cheetah Mobile Blockchain Security Center23). We can effectively provide detail information to resolve the risks of being fake and fraud problems.

Introduction: Since Satoshi Nakamoto published the article "Bitcoin: A Peer-to-Peer Electronic Cash System" in 2008 BIBREF0 , and after the official launch of Bitcoin in 2009, technologies such as blockchain and cryptocurrency have attracted attention from academia and industry. At present, the technologies have been applied to many fields such as medical science, economics, Internet of Things BIBREF1 . Since the launch of Ethereum (Next Generation Encryption Platform) BIBREF2 with smart contract function proposed by Vitalik Buterin in 2015, lots of attention has been obtained on its dedicated cryptocurrency Ether, smart contract, blockchain and its decentralized Ethereum Virtual Machine (EVM). The main reason is that its design method provides developers with the ability to develop Decentralized apps (Dapps), and thus obtain wider applications. A new application paradigm opens the door to many possibilities and opportunities. Initial Coin Offerings (ICOs) is a financing method for the blockchain industry. As an example of financial innovation, ICO provides rapid access to capital for new ventures but suffers from drawbacks relating to non-regulation, considerable risk, and non-accountability. According to a report prepared by Satis Group Crypto Research, around 81% of the total number of ICOs launched since 2017 have turned out to be scams BIBREF3 . Also, according to the inquiry reveals of the University of Pennsylvania that many ICO failed even to promise that they would protect investors against insider self-dealing. Google, Facebook, and Twitter have announced that they will ban advertising of cryptocurrencies, ICO etc. in the future. Fraudulent pyramid selling of virtual currency happens frequently in China. The People’s Bank of China has banned the provision of services for virtual currency transactions and ICO activities. The incredibly huge amount of ICO projects make it difficult for people to recognize its risks. In order to find items of interest, people usually query the social network using the opinion of those items, and then view or further purchase them. In reality, the opinion of social network platforms is the major entrance for users. People are inclined to view or buy the items that have been purchased by many other people, and/or have high review scores. Sentiment analysis is contextual mining of text which identifies and extracts subjective information in the source material and helping a business to understand the social sentiment of their brand, product or service while monitoring online conversations. To resolve the risks and fraud problems, it is important not only to analyze the social-network opinion, but also to scan the smart contract vulnerability detection.

Question: What is the challenge for other language except English
Answer: not researched as much as English