using block.blockhash instead of block.timestamp for 30 minutes

Question

I would like to check if the time has passed 30 minutes before executing a function in my contract. I know how it is done using block.timstamp .. But I want to use block.clockhash as it is more secure... how do I do that?

Answer 1

The usage of block.timestamp has good security properties and you might have misunderstood something. Unless you know what you are doing please stick to block.timestamp.