33. Escrow and time-locks with block.timestamp

`block.timestamp` (seconds since epoch, set by the block producer) is commonly used to gate release logic in escrows, vesting schedules and auctions. It has some producer-controlled slack (usually a few seconds), so avoid using it for anything requiring sub-minute precision.

release_time: public(uint256)

@deploy
def __init__(lock_seconds: uint256):
    self.release_time = block.timestamp + lock_seconds

@external
def withdraw():
    assert block.timestamp >= self.release_time, "still locked"
    send(self.owner, self.balance)

For anything where precise timing is safety-critical (e.g. auction end), prefer block-number-based windows or accept the timestamp's small manipulable margin explicitly in your threat model.

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