In this presentation, we will discuss how to generate a Random Number in Ethereum DAPP. There are four types of methods for generating Random Numbers (Block Variable, Private Contract, OffChain, and Oraclize) We take a view of Random Number method. After than, we point out problems with these methods. We release the Ethereum DAPP statistics for these methods. We will then discuss how to generate secure random numbers in Ethereum DAPP, which is being discussed in the current blockchain. Finally, we discuss how to generate secure random numbers from a penetration testing hacker perspective.