From 3c5aef89d66990b2e81c9bbaf1d53624c81cd6a5 Mon Sep 17 00:00:00 2001 From: Suhas Daftuar Date: Mon, 3 Feb 2020 15:25:27 -0500 Subject: [PATCH] Add BIP-wtxid-relay --- bip-wtxid-relay.mediawiki | 58 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 bip-wtxid-relay.mediawiki diff --git a/bip-wtxid-relay.mediawiki b/bip-wtxid-relay.mediawiki new file mode 100644 index 00000000..df667de1 --- /dev/null +++ b/bip-wtxid-relay.mediawiki @@ -0,0 +1,58 @@ +
+  BIP: ???
+  Layer: Peer Services
+  Title: WTXID-based transaction relay
+  Author: Suhas Daftuar 
+  Comments-Summary: No comments yet.
+  Comments-URI:
+  Status: Draft
+  Type: Standards Track
+  Created: 2020-02-03
+  License: BSD-2-Clause
+
+ +==Abstract== + +This BIP describes two changes to the p2p protocol to support transaction relay +based on the BIP 141 wtxid of a transaction, rather than its txid. + +==Motivation== + +Historically, the INV messages sent on the Bitcoin peer-to-peer network to +announce transactions refer to transactions by their txid, which is a hash of +the transaction that does not include the witness (see BIP 141). This has been +the case even since Segregated Witness (BIP 141/143/144) has been adopted by +the network. + +Not committing to the witness in transaction announcements creates +inefficiencies: because a transaction's witness can be malleated without +altering the txid, a node in receipt of a witness transaction that the node +does not accept will generally still download that same transaction when +announced by other peers. This is because the alternative -- of not downloading +a given txid after rejecting a transaction with that txid -- would allow a +third party to interfere with transaction relay by malleating a transaction's +witness and announcing the resulting invalid transaction to nodes, preventing +relay of the valid version of the transaction as well. + +We can eliminate this concern by using the wtxid in place of the txid when +announcing and fetching transactions. + +==Specification== + +# A new wtxidrelay message is added, which is defined as an empty message where pchCommand == "wtxidrelay". +# The protocol version of nodes implementing this BIP must be set to 70016 or higher. +# The wtxidrelay message must be sent in response to a VERSION message from a peer whose protocol version is >= 70016, and prior to sending a VERACK. +# A new inv type MSG_WTX (0x00000005) is added, for use in both INV messages and GETDATA requests, indicating that the hash being referenced is a transaction's wtxid. In the case of GETDATA requests, MSG_WTX implies that the transaction being requested should be serialized with witness as well, as described in BIP 144. +# After a node has sent and received a "wtxidrelay" message to/from a given peer, the node is required to use the MSG_WTX inv-type when announcing transactions to that peer, or requesting announced transactions from that peer. + +==Backward compatibility== + +As wtxid-based transaction relay is only enabled between peers that both support it, older clients remain fully compatible and interoperable after this change. + +==Implementation== + +https://github.com/bitcoin/bitcoin/pull/18044 + +==Copyright== + +This BIP is licensed under the 2-clause BSD license.