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
|
Return-Path: <ZmnSCPxj@protonmail.com>
Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136])
by lists.linuxfoundation.org (Postfix) with ESMTP id BD615C016E
for <bitcoin-dev@lists.linuxfoundation.org>;
Sun, 7 Jun 2020 00:40:59 +0000 (UTC)
Received: from localhost (localhost [127.0.0.1])
by silver.osuosl.org (Postfix) with ESMTP id 8F5802035E
for <bitcoin-dev@lists.linuxfoundation.org>;
Sun, 7 Jun 2020 00:40:59 +0000 (UTC)
X-Virus-Scanned: amavisd-new at osuosl.org
Received: from silver.osuosl.org ([127.0.0.1])
by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024)
with ESMTP id 7rjH2iL2KiBO
for <bitcoin-dev@lists.linuxfoundation.org>;
Sun, 7 Jun 2020 00:40:57 +0000 (UTC)
X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6
Received: from mail-40130.protonmail.ch (mail-40130.protonmail.ch
[185.70.40.130])
by silver.osuosl.org (Postfix) with ESMTPS id 40C2420352
for <bitcoin-dev@lists.linuxfoundation.org>;
Sun, 7 Jun 2020 00:40:57 +0000 (UTC)
Date: Sun, 07 Jun 2020 00:40:51 +0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com;
s=protonmail; t=1591490454;
bh=sYE1I+4rnrQVM8uOY1ZbYMEoYGSKy8NRVMTVY2X3E/Y=;
h=Date:To:From:Reply-To:Subject:In-Reply-To:References:From;
b=PySVjiERai8tR/h5p35TSGKpSvGV417vhthbfzIuqI2LCKSB4a4Mbmdx1LvC63fZT
KGD26N7dw0V4Eov82YPaC9vVPWTYElZ8eRT9ZYR5kSIiE4WqZAeT8NkhH4p15Iv3aY
SfpsWnuODPlZ/d8rGoiDWiXi1UCWDI3D6BLcwTmM=
To: Mostafa Sedaghat joo <mostafa.sedaghat@gmail.com>,
Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
From: ZmnSCPxj <ZmnSCPxj@protonmail.com>
Reply-To: ZmnSCPxj <ZmnSCPxj@protonmail.com>
Message-ID: <c_8uFmqhKnoFYLB23sjYhJlKAXU5ZoCSQ2MsSgn_OePQoJKFOqIuzMjm7vhnCzevQkAwdJextCeNjA8D-f_p__-sUFSkOFMDI5_yS7k8ZM8=@protonmail.com>
In-Reply-To: <CAJr8eKuFv7R-1HRft-hLFTSdpWUL2uOtkDtisL2+iPaEvvH_hA@mail.gmail.com>
References: <CAJr8eKuFv7R-1HRft-hLFTSdpWUL2uOtkDtisL2+iPaEvvH_hA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [bitcoin-dev] Stamping transaction
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/>
List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org>
List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe>
X-List-Received-Date: Sun, 07 Jun 2020 00:40:59 -0000
Good morning Mostafa,
First off, the proposed mechanism can be made into a softfork by using an u=
nspendable `scriptPubKey` with 0 output value.
For example, a stamp could by convention be any 0-value output whose `scrip=
tPubKey` is `<blockhash> OP_0`, which should be unspendable.
Post-softfork nodes would reject blocks where some transaction is stamped a=
nd the stamped `<blockhash>` is not within the last N blocks.
Pre-softfork nodes would not see anything special about the unspendable `sc=
riptPubKey` and would just accept it (but would not relay such transactions=
due to standardness).
Engineering-wise, block validation now needs to memorize the last N block h=
ashes.
The mempool design currently assumes that a transaction that enters the mem=
pool is always valid unless any UTXOs it spends have been removed.
This is important since miner block selection algorithms assume the mempool=
contains transactions that are currently valid.
Thus, there is the additional need to drop transactions from the mempool if=
they are stamped with a block that has dropped from the stamp TTL.
Another issue is incentives.
The stamp takes up blockchain space that is paid for by the creator of the =
transaction.
Further, the creator of the transaction gains no advantage from the stamped=
transaction; it is others who gain an advantage (the stamped transaction i=
s more likely to be dropped from the mempool).
Discounting the stamp somehow will probably make this into a hardfork.
It might be sneaked into the witness somehow by adding it as a field somewh=
ere in the new parts of Taproot (there is, a new block of data in Taproot t=
hat can be used for this), but note that the cost will still be non-zero (a=
nd users of this feature will still have a disadvantage in that their trans=
actions are more likely to be dropped from the mempool).
Finally, it is expected to increase bandwidth use since a dropped stamped t=
ransaction will probably be rebroadcast with a new stamp, so effectively th=
e transaction is retransmitted again with a different stamp.
Regards,
ZmnSCPxj
|
