This design purposefully does not distinguish leaf nodes from internal nodes. That way it chained invocations can be used to validate paths longer than 32 branches. Do you see a vulnerability due to this lack of distinction?
> On Sep 6, 2017, at 6:59 PM, Russell O'Connor <rocon...@blockstream.io> wrote: > > The fast hash for internal nodes needs to use an IV that is not the standard > SHA-256 IV. Instead needs to use some other fixed value, which should itself > be the SHA-256 hash of some fixed string (e.g. the string "BIP ???" or "Fash > SHA-256"). > > As it stands, I believe someone can claim a leaf node as an internal node by > creating a proof that provides a phony right-hand branch claiming to have > hash 0x80000..0000100 (which is really the padding value for the second half > of a double SHA-256 hash). > > (I was schooled by Peter Todd by a similar issue in the past.) > >> On Wed, Sep 6, 2017 at 8:38 PM, Mark Friedenbach via bitcoin-dev >> <bitcoin-dev@lists.linuxfoundation.org> wrote: >> Fast Merkle Trees >> BIP: https://gist.github.com/maaku/41b0054de0731321d23e9da90ba4ee0a >> Code: https://github.com/maaku/bitcoin/tree/fast-merkle-tree
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