diff --git a/bip-0054.md b/bip-0054.md index 0b856ab5..5734da14 100644 --- a/bip-0054.md +++ b/bip-0054.md @@ -40,8 +40,10 @@ pressures and leading to reduced network security. In computing a block's Merkle root, a transaction with exactly 64 bytes of non-witness data can be interpreted both as an intermediate node in the tree and as a leaf in the tree. This makes it -possible to fake inclusion proofs by pretending a 64-byte block transaction is an inner node, as -well as to pretend the inner nodes on one level of the tree are the actual block transactions. +possible to trick an SPV verifier into accepting an inclusion proof for a transaction that is not +part of a block, by pretending a 64-byte block transaction is actually an inner node. Invalidating +64-byte transactions addresses this vulnerability without requiring users of SPV verifiers to deploy +one of the available mitigations, or even to know one is necessary in the first place. Since [bip-0034][BIP34] activation, explicit [bip-0030][BIP30] validation is not necessary until block height 1,983,702[^0]. Mandating new coinbase transactions be different from the early