Crypto used to mean cryptography - and in the realm of mathematics. Nowadays, everyone wants some crypto for their security schemes. But sometimes people forget is that crypto is hard - and trusting your own crypto is very risky if you don't actually have cryptographers in your team! In this talk, we will review some common crypto failures and how they led to some of the biggest issues we've seen in recent years and conclude with some concrete advice on how to avoid such mistakes, and more importantly where to get advice.