[Bitcoin-development] Proposal: relax the IsStandard rules for P2SH transactions

Wladimir laanwj at gmail.com
Wed Jun 18 07:42:12 UTC 2014

On Tue, Jun 17, 2014 at 9:40 PM, Gavin Andresen
<gavin at bitcoinfoundation.org> wrote:
> Assuming there is rough consensus, I'll make this a pull request (see
> https://github.com/gavinandresen/bitcoin-git/tree/relax_isstandard for code
> changes).
> ----
> Now that we are finally starting to see the use of multi-signature and other
> more complicated transaction forms in applications I think it is time to
> open up the "IsStandard" transaction rules on the main Bitcoin network.


> Discussion
> ----------
> Allowing any P2SH Script would allow an attacker to craft a single standard
> transaction output that requires on the order of 200 ECDSA signature
> checking operations to validate-- an order of magnitude more than is
> currently allowed. Therefore I am proposing that we keep the current
> 15-signature-checking-operations-per-transaction-output limit in place, but
> allow any combination of enabled Script opcodes. So, for example, you might
> have a P2SH Script that is redeemed with 2-of-2 OR 2-of-3 using:

Soungs good to me - to lift the restrictions and increase flexibility,
but also to be a careful and keep the DoS limits.

> The reference implementation's wallet will still only recognize P2SH
> transactions that use one of the standard transaction forms. To actually USE
> a new transaction form will require specialized wallets or specialized
> applications.

That's of course completely separate. As we all know, most wallet
innovation doesn't happen in the reference implementation wallet, and
it should not be used as the guide here.


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