BIP 140 looks like it solves Tx Malleability with least impact on current practices. It is still a soft fork though. Finally, if we were to create an alternative cyptocurrency similar to Bitcoin, a Normalized Tx ID approach would be a better choice if I get it right! ᐧ On Mon, Nov 20, 2017 at 11:15 PM, Johnson Lau wrote: > We can’t “just compute the Transaction ID the same way the hash for > signing the transaction is computed” because with different SIGHASH flags, > there are 6 (actually 256) ways to hash a transaction. > > Also, changing the definition of TxID is a hardfork change, i.e. everyone > are required to upgrade or a chain split will happen. > > It is possible to use “normalised TxID” (BIP140) to fix malleability > issue. As a softfork, BIP140 doesn’t change the definition of TxID. > Instead, the normalised txid (i.e. txid with scriptSig removed) is used > when making signature. Comparing with segwit (BIP141), BIP140 does not have > the side-effect of block size increase, and doesn’t provide any incentive > to control the size of UTXO set. Also, BIP140 makes the UTXO set > permanently bigger, as the database needs to store both txid and normalised > txid > > On 21 Nov 2017, at 1:24 AM, Praveen Baratam via bitcoin-dev < > bitcoin-dev@lists.linuxfoundation.org> wrote: > > Bitcoin Noob here. Please forgive my ignorance. > > From what I understand, in SegWit, the transaction needs to be serialized > into a data structure that is different from the current one where > signatures are separated from the rest of the transaction data. > > Why change the format at all? Why cant we just compute the Transaction ID > the same way the hash for signing the transaction is computed? > > -- > Dr. Praveen Baratam > > about.me > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > -- Dr. Praveen Baratam about.me