Security in CubaCuba is one of the safest countries in the world. It is extremely unlikely that there will be robberies with violence towards a tourist. But be careful, this does not mean that you have to relax completely. There are small robberies every day, for example when one gets confused and leaves his things unattended, etc.
It should also be remembered that scams are the order of the day. Surely, you've heard of the famous jineteros, right? The jineteros are experts in taking the money from the tourists. Basically, it is your profession. You will identify them quickly because they approach with phrases of the type: "Hello friend, where are you from?" And bullshit of the style.
Normally, they offer you cigars that are fake, stolen rum bottles, girls, boys ... Wow, whatever you want. They can also invite you to some “supercool” party, in the end they charge you a lot for the entrance and the party ends up being crap. Do not trust them, all they tell you is a lie.
In addition to the jineteros, they are very likely to try to rip you off in some stores, supermarkets and restaurants. Ask for prices before buying and count the returns every time you pay. One of the most classic scams is with water bottles. The normal price is 0.7 CUC and they should give you a receipt if it is a state store. Many times they charge 1.5 CUC or 2 CUC and do not give you a receipt. That is, they stay the difference.