4 ms·

> Every Ethereum block contains a timestamp which smart contracts can read, so it's trivial to write code that only allows withdrawals in 1 month intervals Not

• DennisP 8y ago
  True if you're being really fine-grained about it, like using the timestamp as the seed of a random number generator. However, on the scale of a month, the miners aren't going to be able to mess with you. A block stamped with a significantly incorrect timestamp won't be accepted by other miners.
  • Drdrdrq 8y ago
    Are you sure about that? I was under the impression that there were no checks whatsoever and it's only a goodwill of miners (and lack of incentive to do otherwise) that provides somewhat accurate time. On the flip side, I'm sure there are/will be oracles for approx. block time, so this is still a solveable issue.
    • DennisP 8y ago
      Here's a spec from 2015: https://github.com/ethereum/wiki/blob/c02254611f218f43cbb07517ca8e5d00fd6d6d75/Block-Protocol-2.0.md https://github.com/ethereum/wiki/blob/c02254611f218f43cbb075... From the block validation section: "Is block.timestamp <= now + 900 and is block.timestamp >= parent.timestamp?" (In Solidity, block.timestamp is in seconds, and I think that's a direct translation from the underlying opcode, so I assume it's 900 seconds here.)
      • Drdrdrq 8y ago
        I stand corrected - it seems blocks' time must be increasing and must not be more than 15 minutes in the future, according to clocks of validating miners. Thanks, didn't know that!