Cryptography. Debunking the myth of omnipotent intelligence services

"There's no point in defending yourself, the FSB has access to everything anyway" - these are the words you can often hear online. Many people think that there's no point in confronting the special services, you can only hope for the best. In fact, this is not true. For example, with the help of cryptography, you can protect your data so that the security forces won't be able to get to it. The weak link here is the user himself. You will learn how this happens in practice.