[bitcoin-dev] BIP draft: HTLC transactions

Sean Bowe sean at z.cash
Wed Jul 20 04:35:39 UTC 2016

I'm requesting feedback for Hash Time-Locked Contract (HTLC) transactions
in Bitcoin.

HTLC transactions allow you to pay for the preimage of a hash. CSV/CLTV can
be used to recover your funds if the other party is not cooperative. These
scripts take the following general form:

    [HASHOP] <digest> OP_EQUAL
        <seller pubkey>
        <num> [TIMEOUTOP] OP_DROP <buyer pubkey>

These transactions are useful for both the Lightning network and in
zero-knowledge contingent payments. This very script (using CLTV and
SHA256) was used as part of our "pay-to-sudoku" ZKCP demo earlier this
year: https://github.com/zcash/pay-to-sudoku

Members of the community have expressed the desire for a BIP to submitted
in coordination with changes to Bitcoin Core that support these
transactions in the wallet.

Please review my draft BIP here:

An implementation is being worked on here:


Sean Bowe
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20160719/2976c883/attachment.html>

More information about the bitcoin-dev mailing list