I'm working to develop an algorithmic code methodology which will be "easy" to code and arbitrarily difficult to hack.
My ultimate goal is to provide a framework to create smart contracts without a need for anything like the Ethereum blockchain.
In order to test this I provide hacking challenges with BTC private keys embedded in hackable lock boxes.
My latest challenge is labeled 4.0 and you can find all the details here:
Reports on many past challenges are available at this website as well.