From: Praveen Baratam <praveen.baratam@gmail•com>
To: Johnson Lau <jl2012@xbt•hk>
Cc: bitcoin-dev <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Why SegWit Anyway?
Date: Mon, 20 Nov 2017 23:37:40 +0530 [thread overview]
Message-ID: <CAAQs3wth=04PxDL6XzjTVYyZBiM1ZYHTK9-qRP8W+DAb53xMGg@mail.gmail.com> (raw)
In-Reply-To: <F392E62C-00CF-4D91-BB6B-706F2A59C63B@xbt.hk>
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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 <jl2012@xbt•hk> 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 <http://about.me/praveen.baratam>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists•linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>
>
--
Dr. Praveen Baratam
about.me <http://about.me/praveen.baratam>
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next prev parent reply other threads:[~2017-11-20 18:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-20 17:24 Praveen Baratam
2017-11-20 17:39 ` Ariel Lorenzo-Luaces
2017-11-20 17:45 ` Johnson Lau
[not found] ` <CAAUFj10ZRQrtEzB_2wp-WS8Q-FGcSegpc_Z6kqvqnDLzNn=DrA@mail.gmail.com>
[not found] ` <CAAUFj11_Vh2K4MrmuBre5KaX6F16Jg3PYAsj6SSfzoYYRz_WyA@mail.gmail.com>
2017-11-20 18:04 ` Dan Bryant
2017-11-21 13:10 ` Steve Shadders
2017-11-21 13:16 ` Adán Sánchez de Pedro Crespo
2017-11-25 15:41 ` CANNON
2017-11-20 18:07 ` Praveen Baratam [this message]
2017-11-20 19:58 ` Johnson Lau
2017-11-20 18:59 ` Gregory Maxwell
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