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Date: Wed, 10 Apr 2013 02:53:16 -0400
From: Peter Todd <pete@petertodd.org>
To: Gregory Maxwell <gmaxwell@gmail.com>
Message-ID: <20130410065316.GA31965@savin>
References: <CAAS2fgSkiqfhJxHJNw8i8G5yd1XY6tUTDynQ+AekbwmHP_jZmw@mail.gmail.com>
	<20130410030301.GA9921@savin>
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Cc: Bitcoin Development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development]
 =?utf-8?q?To_prevent_arbitrary_data_storage?=
 =?utf-8?q?_in_txouts_=E2=80=94_The_Ultimate_Solution?=
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On Tue, Apr 09, 2013 at 11:03:01PM -0400, Peter Todd wrote:
> On Tue, Apr 09, 2013 at 07:53:38PM -0700, Gregory Maxwell wrote:
>=20
> Note how we can already do this: P2SH uses Hash160, which is
> RIPE160(SHA256(d)) We still need a new P2SH *address* type, that
> provides the full 256 bits, but no-one uses P2SH addresses yet anyway.

We can keep the length 160bits:

scriptPubKey: OP_HASH160 OP_HASH160 <Hash160(P2SHv2 address)> OP_EQUALVERIFY

You don't need to change the address type at all if new software is
written to check for both forms of txout in the actual
blockchain/transaction code at the deeper level. Basically now a P2SH
address could actually mean one of two scriptPubKey forms, must like a
normal address can mean either the hashed or bare OP_CHECKSIG form.


Of course, either way you have the odd side-effect that it's now
difficult to pay further funds to a random txout seen on the
blockchain... strange, although possibly not a bad thing.

--=20
'peter'[:-1]@petertodd.org

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