From: woltx <woltx@protonmail•com>
To: "bitcoin-dev@lists•linuxfoundation.org"
<bitcoin-dev@lists•linuxfoundation.org>
Subject: [bitcoin-dev] Silent Payment v4 (coinjoin support added)
Date: Tue, 11 Oct 2022 07:02:47 +0000 [thread overview]
Message-ID: <P_21MLHGJicZ-hkbC4DGu86c5BtNKiH8spY4TOw5FJsfimdi_6VyHzU_y-s1mZsOcC2FA3EW_6w6W5qfV9dRK_7AvTAxDlwVfU-yhWZPEuo=@protonmail.com> (raw)
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Silent Payment v4 (coinjoin support added)
Changes:
. Silent payments now use all inputs to create transactions. Previously, they only used the first input. This change increases privacy and makes silent payments compatible with coinjoin.
. `getspaddress` RPC renamed to `getsilentaddress` for clarity
. Added support for silent payment in PSBT via `walletcreatefundedpsbt` RPC.
. Added a new index scheme (which stores the sum of input public keys for each transaction). The previous index `bitcoin/signet/indexes/silentpaymentindex` should be removed as it is no longer compatible with this new version.
For reviewers:
Now, silent payments use the scheme `hash(i1*X + i2*X + i3*X + ...)*G + X == hash(x*(I1+I2+I3+...))*G + X`, as described here: https://gist.github.com/RubenSomsen/c43b79517e7cb701ebf77eec6dbb46b8#variant-using-all-inputs
As inputs can be Taproot, this introduced a new issue as `bitcoin-core/secp256k1` does not support x-only public key sum (perhaps due to missing prefix byte).
I opened a new PR (#1143) to add a function to convert from x-only to compressed public key with even y. This is the solution being used by the current silent payment implementation.
Tutorial updated: https://gist.github.com/w0xlt/c81277ae8677b6c0d3dd073893210875
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next reply other threads:[~2022-10-11 7:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-11 7:02 woltx [this message]
2022-10-12 9:04 ` alicexbt
2022-10-23 7:00 ` woltx
2022-10-23 20:54 ` alicexbt
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