# Gavin Andresen
# 2011-02-14 21:12:30
# https://bitcointalk.org/index.php?topic=3441.msg48852#msg48852

@s{quotedtext}
@s{quotedtext}
 @p{brk}
Right... so then the question is "will the MYBITCOIN-like intermediary be able to verify transactions quickly without opening themselves up to systematic fraud." @p{par}

Without requiring users to pre-deposit funds with them, because users ain't gonna do that. @p{par}

Here's another possible simple rule for miners that might work (but, as Hal said, requires Deep Thought): @p{par}

"When I see a new block with transactions that I didn't see broadcast previously, mark those transactions as suspicious.  If I see double-spends of those transactions, stop building on that block@p{--} assume it is cheating.  Switch to the previous block (or alternate block if there's a block race going on)." @p{par}

Miners won't try to rip off a grocery store for $50 worth of groceries if doing so makes their $50+ bitcoin reward for finding a block disappear. @p{par}

This rule would also give miners a strong incentive to detect and refuse to include EITHER side of a double-spend in their blocks (if they get both spends while they're working on the block). @p{brk}