From: Tamas Blummer <tamas.blummer@gmail.com>
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Date: Sun, 3 Jun 2018 00:02:11 +0200
In-Reply-To: <20180602124157.744x7j4u7dqtaa43@email>
To: "David A. Harding" <dave@dtrt.org>,
	Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
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Subject: Re: [bitcoin-dev] BIP 158 Flexibility and Filter Size
Precedence: list


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Without block commitment mobiles would have to use trusted filter =
provider or implement a complex data hungry algorithm and still remain =
as insecure as with BIP 37.

Years of experience implementing wallets with BIP 37 taught us that an =
outpoint + output script filter is useful. Committing such a filter to =
the block can not be an error.

We could roll this out on P2P prior to a soft fork adding the =
commitment, but I would not expect its use to pick up before that.
Therafter BIP 37 could be rightfully decommissioned, herby offering both =
security and privacy enhancement at modest data cost.

Tamas Blummer

> On Jun 2, 2018, at 14:41, David A. Harding via bitcoin-dev =
<bitcoin-dev@lists.linuxfoundation.org> wrote:
>=20
> On Fri, Jun 01, 2018 at 07:02:38PM -0700, Jim Posen via bitcoin-dev =
wrote:
>> Without the ability to verify filter validity, a client would have to =
stop
>> syncing altogether in the presence of just one malicious peer, which =
is
>> unacceptable.
>=20
> I'm confused about why this would be the case.  If Alice's node
> generates filters accurately and Mallory's node generates filters
> inaccurately, and they both send their filters to Bob, won't Bob be =
able
> to download any blocks either filter indicates are relevant to his
> wallet?


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