Solidity Interview Question: How Do You Prevent Timestamp Manipulation in Smart Contract Auctions?
How do you stop miners from manipulating block.timestamp in Solidity auctions where timing matters? I faced this in a recent Solidity interview and want advice from anyone who’s solved it.
I built a smart contract for an auction that starts and ends using timestamps. The interviewer said miners can adjust timestamps slightly, which could change the auction’s end time unfairly. Using block.number isn’t reliable because block times vary. Oracles add too much gas cost.
I suggested averaging block times or mixing timestamps with block numbers. The interviewer said those ideas are either too complex or still vulnerable.
What’s the best way to prevent timestamp manipulation in Solidity smart contracts? Are there proven, simple patterns that keep auctions fair and efficient? If you’ve handled this in interviews or real projects, I’d love your advice.