Write your own (encryption algorithm, password hash mechanism, bitcoin wallet) take your pick. Rolling your own crypto is high-risk in itself and the risk goes

Write your own (encryption algorithm, password hash mechanism, bitcoin wallet) take your pick. Rolling your own crypto is high-risk in itself and the risk goes up the more value in what you're protecting with it. Using it to protect drug cartel communications seems about as high risk as you can go... I bet there would be some serious repercussions when they got busted because of a failure in your code...