Technically, i changed my mind after reviewing more on FlexTrans - it may be more simple that “Simple Malleability Fix” because it only changes the transaction format. It doesn’t add a second txid/utxid like SegWit and Simple Mal Fix, which would complicate node and client code in a different way.
Simple MalFix is not complete with the current code (see Tom Zander comment):
This introduction of a second ID for transactions seems to have a wide ranging set of effects, from your commit messages it seems that this means a node can no longer accept transactions it does not have the parents of, because it becomes impossible to ask the sending node for them like Bitcoin does today.
Basically the decision is to use 2 txids (txid + wtxid|utxid) (SegWit and Simple MalFix), or use a single txid + tx version (FlexTrans v4).
However, nothing uses it except Tom Zander’s abandoned Bitcoin Classic testnet code. That goes against the Peercoin objective to be a drop-in Bitcoin replacement.
I can see why Bitcoin Cash still hasn’t implemented Simple MalFix. Its weird cause i think they changed signatures already but no malfix.
I was happy that Peercoin is going to implement RFC #0004 Remove Transaction Timestamp, because the raw tx format would now match Bitcoin’s (as well as simplifying and fixing the code). The only wrinkle is that Peercoin uses 1e6 “satoshis” per coin vs. Bitcoin’s 1e8 satoshis per coin, which affects serialization of the raw tx outputs (by client apps, not so much the nodes).
Original Bitcoin raw tx format:
Original Peercoin raw tx format:
SegWit raw tx format:
Simple Mal Fix Bitcoin raw tx format (replaces inputs txid with utxid):
FlexTrans format with CMF (main sections, but token order is flexible)
Possible CMF Tokens (could be easily extended later):
I don’t know why i went into all this, i just wanted to dig deeper and document on the technical stuff, which was part of the original post point. We are in a decentralized network space, things are not just engineering matters, consensus matters, and people vote with their feet.