1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
|
Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192]
helo=mx.sourceforge.net)
by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76)
(envelope-from <1240902@gmail.com>) id 1Z5wiu-0008IZ-7j
for bitcoin-development@lists.sourceforge.net;
Fri, 19 Jun 2015 13:52:48 +0000
Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com
designates 74.125.82.50 as permitted sender)
client-ip=74.125.82.50; envelope-from=1240902@gmail.com;
helo=mail-wg0-f50.google.com;
Received: from mail-wg0-f50.google.com ([74.125.82.50])
by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128)
(Exim 4.76) id 1Z5wis-0001sn-SV
for bitcoin-development@lists.sourceforge.net;
Fri, 19 Jun 2015 13:52:48 +0000
Received: by wgfq1 with SMTP id q1so43672607wgf.1
for <bitcoin-development@lists.sourceforge.net>;
Fri, 19 Jun 2015 06:52:40 -0700 (PDT)
MIME-Version: 1.0
X-Received: by 10.180.80.9 with SMTP id n9mr6897968wix.87.1434721960888; Fri,
19 Jun 2015 06:52:40 -0700 (PDT)
Received: by 10.180.208.69 with HTTP; Fri, 19 Jun 2015 06:52:40 -0700 (PDT)
In-Reply-To: <20150619134408.GB27280@savin.petertodd.org>
References: <20150619103959.GA32315@savin.petertodd.org>
<CABHVRKR7bXfDX0_frAv_Ph4Saz3SXwXeZae1DEokorvekPeinw@mail.gmail.com>
<20150619134408.GB27280@savin.petertodd.org>
Date: Fri, 19 Jun 2015 21:52:40 +0800
Message-ID: <CAFzgq-zbcARe4ePj_3wA9mEzKE3PsGQ3Kb0-ALyTk054uzrrTA@mail.gmail.com>
From: Chun Wang <1240902@gmail.com>
To: Peter Todd <pete@petertodd.org>
Content-Type: text/plain; charset=UTF-8
X-Spam-Score: -1.4 (-)
X-Spam-Report: Spam Filtering performed by mx.sourceforge.net.
See http://spamassassin.org/tag/ for more details.
-1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for
sender-domain
0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider
(1240902[at]gmail.com)
-0.0 SPF_PASS SPF: sender matches SPF record
0.2 FREEMAIL_ENVFROM_END_DIGIT Envelope-from freemail username ends in
digit (1240902[at]gmail.com)
-0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from
author's domain
0.1 DKIM_SIGNED Message has a DKIM or DK signature,
not necessarily valid
-0.1 DKIM_VALID Message has at least one valid DKIM or DK signature
X-Headers-End: 1Z5wis-0001sn-SV
Cc: bitcoin-development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] F2Pool has enabled full replace-by-fee
X-BeenThere: bitcoin-development@lists.sourceforge.net
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: <bitcoin-development.lists.sourceforge.net>
List-Unsubscribe: <https://lists.sourceforge.net/lists/listinfo/bitcoin-development>,
<mailto:bitcoin-development-request@lists.sourceforge.net?subject=unsubscribe>
List-Archive: <http://sourceforge.net/mailarchive/forum.php?forum_name=bitcoin-development>
List-Post: <mailto:bitcoin-development@lists.sourceforge.net>
List-Help: <mailto:bitcoin-development-request@lists.sourceforge.net?subject=help>
List-Subscribe: <https://lists.sourceforge.net/lists/listinfo/bitcoin-development>,
<mailto:bitcoin-development-request@lists.sourceforge.net?subject=subscribe>
X-List-Received-Date: Fri, 19 Jun 2015 13:52:48 -0000
Before F2Pool's launch, I performed probably the only successful
bitcoin double spend in the March 2013 fork without any mining power.
[ https://bitcointalk.org/index.php?topic=152348.0 ] I know how bad
the full RBF is. We are going to switch to FSS RBF in a few hours.
Sorry.
On Fri, Jun 19, 2015 at 9:44 PM, Peter Todd <pete@petertodd.org> wrote:
> On Fri, Jun 19, 2015 at 09:33:05AM -0400, Stephen Morse wrote:
>> It is disappointing that F2Pool would enable full RBF when the safe
>> alternative, first-seen-safe RBF, is also available, especially since the
>> fees they would gain by supporting full RBF over FSS RBF would likely be
>> negligible. Did they consider using FSS RBF instead?
>
> Specifically the following is what I told them:
>
>> We are
>> interested in the replace-by-fee patch, but I am not following the
>> development closely, more background info is needed, like what the
>> difference between standard and zeroconf versions? Thanks.
>
> Great!
>
> Basically both let you replace one transaction with another that pays a
> higher fee. First-seen-safe replace-by-fee adds the additional criteria
> that all outputs of the old transaction still need to be paid by the new
> transaction, with >= as many Bitcoins. Basically, it makes sure that if
> someone was paid by tx1, then tx2 will still pay them.
>
> I've written about how wallets can use RBF and FSS-RBF to more
> efficiently use the blockchain on the bitcoin-development mailing list:
>
> http://www.mail-archive.com/bitcoin-development@lists.sourceforge.net/msg07813.html
> http://www.mail-archive.com/bitcoin-development@lists.sourceforge.net/msg07829.html
>
> Basically, for the purpose of increasing fees, RBF is something like %50
> cheaper than CPFP, and FSS-RBF is something like %25 cheaper.
>
> In addition, for ease of implementation, my new FSS-RBF has a number of
> other restrictions. For instance, you can't replace multiple
> transactions with one, you can't replace a transaction whose outputs
> have already been spent, you can't replace a transaction with one that
> spends additional unconfirmed inputs, etc. These restrictions aren't
> "set in stone", but they do make the code simpler and less likely to
> have bugs.
>
> In comparison my previous standard RBF patch can replace multiple
> transactions with one, can replace long chains of transactions, etc.
> It's willing to do more computation before deciding if a transaction
> should be replaced, with more complex logic; it probably has a higher
> chance of having a bug or DoS attack.
>
> You've probably seen the huge controversy around zeroconf with regard to
> standard replace-by-fee. While FSS RBF doesn't make zeroconf any safer,
> it also doesn't make it any more dangerous, so politically with regard
> to zeroconf it makes no difference. You *can* still use it doublespend
> by taking advantage of how different transactions are accepted
> differently, but that's true of *every* change we've ever made to
> Bitcoin Core - by upgrading to v0.10 from v0.9 you've also "broken"
> zeroconf in the same way.
>
>
> Having said that... honestly, zeroconf is pretty broken already. Only
> with pretty heroic measures like connecting to a significant fraction of
> the Bitcoin network at once, as well as connecting to getblocktemplate
> supporting miners to figure out what transactions are being mined, are
> services having any hope of avoiding getting ripped off. For the average
> user their wallets do a terrible job of showing whether or not an
> unconfirmed transaction will go through. For example, Schildbach's
> Bitcoin wallet for Android has no code at all to detect double-spends
> until they get mined, and I've been able to trick it into showing
> completely invalid transactions. In fact, currently Bitcoin XT will
> relay invalid transactions that are doublepsends, and Schildbach's
> wallet displays them as valid, unconfirmed, payments. It's really no
> surprise to me that nearly no-one in the Bitcoin ecosystem accepts
> unconfirmed transactions without some kind of protection that doesn't
> rely on first-seen-safe mempool behavior. For instance, many ATM's these
> days know who their customers are due to AML requirements, so while you
> can deposit Bitcoins and get your funds instantly, the protection for
> the ATM operator is that they can go to the police if you rip them off;
> I've spoken to ATM operators who didn't do this who've lost hundreds or
> even thousands of dollars before giving up on zeroconf.
>
> My big worry with zeroconf is a service like Coinbase or Shapeshift
> coming to rely on it, and then attempting to secure it by gaining
> control of a majority of hashing power. For instance, if Coinbase had
> contracts with 80% of the Bitcoin hashing power to guarantee their
> transactions would get mined, but 20% of the hashing power didn't sign
> up, then the only way to guarantee their transactions could be for the
> 80% to not build on blocks containing doublespends by the 20%. There's
> no way in a decentralized network to come to consensus about what
> transactions are or are not valid without mining itself, so you could
> end up in a situation where unless you're part of one of the big pools
> you can't reliably mine at all because your blocks may get rejected for
> containing doublespends.
>
> One of my goal with standard replace-by-fee is to prevent this scenario
> by forcing merchants and others to implement ways of accepting zeroconf
> transactions safely that work in a decentralized environment regardless
> of what miners do; we have a stronger and safer Bitcoin ecosystem if
> we're relying on math rather than trust to secure our zeroconf
> transactions. We're also being more honest to users, who right now often
> have the very wrong impression that unconfirmed transactions are safe to
> accept - this does get people ripped off all too often!
>
>
> Anyway, sorry for the rant! FWIW I updated my FSS-RBF patch and am
> waiting to get some feedback:
>
> https://github.com/bitcoin/bitcoin/pull/6176
>
> Suhas Daftuar did find a pretty serious bug in it, now fixed. I'm
> working on porting it to v0.10.2, and once that's done I'm going to put
> up a bounty for anyone who can find a DoS attack in the patch. If no-one
> claims the bounty after a week or two I think I'll start feeling
> confident about using it in production.
>
>
> --
> 'peter'[:-1]@petertodd.org
> 000000000000000003188926be14e5fbe2f8f9c63c9fb8e2ba4b14ab04f1c9ab
>
> ------------------------------------------------------------------------------
>
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>
|