Subject: Re: [bitcoin-dev] BIP 158 Flexibility and Filter Size

From: Tamas Blummer <[email-masked]>
Date: Sun, 3 Jun 2018 00:02:11 +0200

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 <[email-masked]> wrote:
> 
> 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.
> 
> 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?