This thesis researches different ransomwares, how we can stop them and how their threat vectors work. It is important to notice that when solving one ransomware doesn’t solve the next incoming one. In this thesis we investigate six different ransomwares that spread between 2016-2019. We investigate the encryption methods, the different threat vectors, infection spreading and how to prevent from them by doing a theoretical and practical study. The results show that after infection of a ransomware, it encrypts the data instantaneously on the system. Fortunately, to keep information safe there are few prevention methods such as anti-virus software and a few prototypes created that is not currently released one is called PayBreak for Windows 7 and tests to find a solution through flash memory.