In this talk I will show you how to use standard playing cards in order to run cryptographic protocols in a visual and easy way. We will focus on the problem of “Multi-party computation”, which I introduce with the following question: How can two millionaires learn who is richer without revealing the actual amount of money they have? The talk will be interactive and accessible to everyone. You will learn how to run the protocols and play with cards during the talk. I hope you will improve your knowledge and interest in Cryptography. References: Report 2017/423 and Report 2017/863.