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From: rhavar@protonmail.com
To: Gregory Maxwell <greg@xiph.org>,
	Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Transaction Input/Output Sorting
Date: Wed, 24 Oct 2018 18:21:00 +0000	[thread overview]
Message-ID: <Go9kJfeEX3i-XIzmj5a59kLbyAsnQDHpeDGnLrmHuL1m9XjfOMH_Cz5zs1Q48wloikgR2ww75qqhlWRopmm8aXIZADTaRBxZThpIHl3Cteo=@protonmail.com> (raw)
In-Reply-To: <tQ_qHfmyWnGXpNVKNhuMEcHB7h1y9dJolTi0dGHi_vhRcV9bRJJXUPbvVc5QAptwruQ8cK1kxBYryhg4AzLX52uZ1Y7pgVONOVBxG25-8fU=@protonmail.com>

Actually, I think it can be calculated a bit smarter using maths (which unfortunately I'm not very good at...). But I assume it's something like:

```
falsePositiveChances := 0.0

foreach( transaction of transactions) {
	falsePositiveChances += (1 / factorial(transaction.Inputs)) * (1 / factorial(transaction.Ouputs))
}

totalFalsePositives := falsePositiveChances / transactions.length
```

If so, I get 42.4% false positive rate. So clearly bip69 is getting used a fair bit, but not nearly as much as randomization.


-Ryan

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Wednesday, October 24, 2018 10:52 AM, <rhavar@protonmail.com> wrote:

> That's pretty easy to quantify. I wrote a quick script to grab the last few blocks, and then shuffle the inputs/outputs before testing if each transaction is bip69 or not.
>
> The result was 42% of all transactions would accidentally be bip69 when randomized.
>
> So clearly randomization is a lot more popular than bip69 at the moment, but I'm not sure that it matters much. As soon as you have more than a few inputs/outputs, you can tell with a high confidence if the transaction is bip69 or not.
>
> And of course if you're clustering a wallet, you can figure out extremely easily how that wallet behaves wrt bip6.
>
> -Ryan
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> On Wednesday, October 24, 2018 9:12 AM, Gregory Maxwell via bitcoin-dev bitcoin-dev@lists.linuxfoundation.org wrote:
>
> > On Wed, Oct 24, 2018 at 3:52 PM Chris Belcher via bitcoin-dev
> > bitcoin-dev@lists.linuxfoundation.org wrote:
> >
> > > Thanks for bringing our attention to this important topic.
> > > According to (https://p2sh.info/dashboard/db/bip-69-stats) around 60% of
> > > transaction follow bip69 (possibly just by chance).
> >
> > A two input randomly ordered transaction has a 50% chance of
> > 'following' bip-69. So 60% sound like a small minority.




      reply	other threads:[~2018-10-24 18:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-21 19:00 [bitcoin-dev] Transaction Input/Output Sorting rhavar
2018-10-21 21:54 ` Pavol Rusnak
2018-10-22  1:54   ` rhavar
2018-10-23 14:29     ` Chris Belcher
2018-10-24 16:12       ` Gregory Maxwell
2018-10-24 17:52         ` rhavar
2018-10-24 18:21           ` rhavar [this message]

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