From d873db7f8ff37c37f9c72482d8ecd52282f4438e Mon Sep 17 00:00:00 2001 From: Antoine Poinsot Date: Thu, 2 Sep 2021 13:41:28 +0200 Subject: policy: document we intentionally don't lower the dust threshold for Taproot A "correction" of what seemed to be an overlook was initially proposed in PR #22779. It was deemed unnecessary to further reduce the dust level, so document the intention. Signed-off-by: Antoine Poinsot --- src/policy/policy.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'src/policy') diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp index 9e433584e7..fced397e51 100644 --- a/src/policy/policy.cpp +++ b/src/policy/policy.cpp @@ -22,7 +22,7 @@ CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn) // so dust is a spendable txout less than // 182*dustRelayFee/1000 (in satoshis). // 546 satoshis at the default rate of 3000 sat/kvB. - // A typical spendable segwit txout is 31 bytes big, and will + // A typical spendable segwit P2WPKH txout is 31 bytes big, and will // need a CTxIn of at least 67 bytes to spend: // so dust is a spendable txout less than // 98*dustRelayFee/1000 (in satoshis). @@ -34,6 +34,11 @@ CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn) int witnessversion = 0; std::vector witnessprogram; + // Note this computation is for spending a Segwit v0 P2WPKH output (a 33 bytes + // public key + an ECDSA signature). For Segwit v1 Taproot outputs the minimum + // satisfaction is lower (a single BIP340 signature) but this computation was + // kept to not further reduce the dust level. + // See discussion in https://github.com/bitcoin/bitcoin/pull/22779 for details. if (txout.scriptPubKey.IsWitnessProgram(witnessversion, witnessprogram)) { // sum the sizes of the parts of a transaction input // with 75% segwit discount applied to the script size. -- cgit v1.2.3