diff --git a/ch07.asciidoc b/ch07.asciidoc index a3404b7c..ef2feb76 100644 --- a/ch07.asciidoc +++ b/ch07.asciidoc @@ -416,7 +416,7 @@ Today, this attack is not very lucrative, because block reward is much higher th To prevent "fee sniping," when Bitcoin Core creates transactions, it uses +nLocktime+ to limit them to the "next block," by default. In our scenario, Bitcoin Core would set +nLocktime+ to 100,001 on any transaction it created. Under normal circumstances, this +nLocktime+ has no effect—the transactions could only be included in block #100,001 anyway; it's the next block. -But under a blockchain fork attack, the miners would not be able to pull high-fee transactions from the mempool, because all those transactions would be timelocked to block #100,001. They can only remine #100,000 with whatever transactions were valid at that time, essentially gaining no new fees. +But under a blockchain fork/double-spend attack, the miners would not be able to pull high-fee transactions from the mempool, because all those transactions would be timelocked to block #100,001. They can only remine #100,000 with whatever transactions were valid at that time, essentially gaining no new fees. To achieve this, Bitcoin Core sets the +nLocktime+ on all new transactions to and sets the +nSequence+ on all the inputs to 0xFFFFFFFE to enable +nLocktime+.((("", startref="Stimelock07")))