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
|
Return-Path: <jl2012@xbt.hk>
Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org
[172.17.192.35])
by mail.linuxfoundation.org (Postfix) with ESMTPS id CD67349F
for <bitcoin-dev@lists.linuxfoundation.org>;
Sat, 22 Dec 2018 16:56:43 +0000 (UTC)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
Received: from sender-of-o51.zoho.com (sender-of-o51.zoho.com [135.84.80.216])
by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 3E9B5CF
for <bitcoin-dev@lists.linuxfoundation.org>;
Sat, 22 Dec 2018 16:56:42 +0000 (UTC)
ARC-Seal: i=1; a=rsa-sha256; t=1545497796; cv=none; d=zoho.com; s=zohoarc;
b=cw5gQtlwjOnfbgZKtB7XH5jKJ0tyMqL0wmmZaomLLaEH4+m+J7khoClUsHrqb4QU2CNqx5xmqVP7aD6M65E2CnBGTaN7fCJqyVjQv+YwUnAXEeep77IKZkScNI08kTB+g10GI7Y6klPqq4EsJcA7tZafFmiIy14DyIukweCSrPw=
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com;
s=zohoarc; t=1545497796;
h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To:ARC-Authentication-Results;
bh=i4heNDv/Iof8aXNHOEx104O7ColF8uPlhq6cNq7ybIg=;
b=grJ8X2LiLiOtZQY58cIFBhWSLlppEx7gp1LfXFrh17wPW3zIVGAhrFBfngoNYwRWEJom0Bmpn2m7c2a6V3LVVz94pC0VuqbCiTq8TSOq9hKKw1gI90K0VhjQhSNv8/n070hZtRok1leNkE3bUOVlYpEAqCRKN8hAphBNAjNNh3Q=
ARC-Authentication-Results: i=1; mx.zoho.com; dkim=pass header.i=xbt.hk;
spf=pass smtp.mailfrom=jl2012@xbt.hk;
dmarc=pass header.from=<jl2012@xbt.hk> header.from=<jl2012@xbt.hk>
Received: from [10.8.0.105] (n218103234118.netvigator.com [218.103.234.118])
by mx.zohomail.com with SMTPS id 1545497794572562.9421070731885;
Sat, 22 Dec 2018 08:56:34 -0800 (PST)
Content-Type: text/plain;
charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 12.0 \(3445.100.39\))
From: Johnson Lau <jl2012@xbt.hk>
In-Reply-To: <KFCfNAmHhRvsDJs70UW3l4ssqBtdBrb8gYP5A3cN2hsTPrXVg7f5Yrt2LOo5V0QdAhhoooc3lllXxiiXSVt_28obYBl_XKAgEQkGg1kOj8I=@protonmail.com>
Date: Sun, 23 Dec 2018 00:56:29 +0800
Content-Transfer-Encoding: quoted-printable
Message-Id: <CAABEECD-2B12-4852-A440-58809EB6BF56@xbt.hk>
References: <9F8C0789-48E9-448A-A239-DB4AFB902A00@xbt.hk>
<8z5NQkaOUo9z-wdBphQtZrxIf7OCtVQFvK3neMWvcRsngld5XJs-vt7CLuY46ZOp_pX8gEd92pMdkEkp8CUOMH9lUTw5ocWsbDPiaKdSa2I=@protonmail.com>
<34B38940-524D-42B9-8A67-6A62DCE04665@xbt.hk>
<KFCfNAmHhRvsDJs70UW3l4ssqBtdBrb8gYP5A3cN2hsTPrXVg7f5Yrt2LOo5V0QdAhhoooc3lllXxiiXSVt_28obYBl_XKAgEQkGg1kOj8I=@protonmail.com>
To: ZmnSCPxj <ZmnSCPxj@protonmail.com>
X-Mailer: Apple Mail (2.3445.100.39)
X-ZohoMailClient: External
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE
autolearn=ham version=3.3.1
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
smtp1.linux-foundation.org
X-Mailman-Approved-At: Sun, 23 Dec 2018 18:43:54 +0000
Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Safer NOINPUT with output tagging
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.12
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: Sat, 22 Dec 2018 16:56:44 -0000
> On 22 Dec 2018, at 10:25 PM, ZmnSCPxj <ZmnSCPxj@protonmail.com> wrote:
>=20
> Good morning Johnson,
>=20
>> Generally speaking, I think walletless protocol is needed only when =
you want to rely a third party to open a offchain smart contract. It =
could be coinswap, eltoo, or anything similar.
>=20
> I think a third party would be pointless in general, but then I am =
strongly against custodiality.
>=20
> The idea is that you have some kind of hardware wallet or similar =
"somewhat cold" storage *that you control yourself*, and crate channels =
for your hot offchain Lightning wallet, without adding more transactions =
from your somewhat-cold storage to your hot offchain Lightning wallet on =
the blockchain.
>=20
> Then you could feed a set of addresses to the hot offchain wallet =
(addresses your somewhat-cold storage controls) so that when channels =
are closed, the funds go to your somwhat-cold storage.
>=20
> I also doubt that any custodial service would want to mess around with =
deducting funds from what the user input as the desired payment. I have =
not seen a custodial service that does so (this is not a scientific =
study; I rarely use custodial services); custodial services will deduct =
more from your balance than what you send, but will not modify what you =
send, and will prevent you from sending more than your balance minus the =
fees they charge for sending onchain.
>=20
> Even today, custodial services deducting from your sent value (rather =
than the balance remaining after you send) would be problematic when =
interacting with merchants (or their payment processors) accepting =
onchain payments; the merchant would refuse to service a lower value =
than what it charges and it may be very technically difficult to recover =
such funds from the merchant.
> I expect such a custodial service would quickly lose users, but the =
world surprises me often.
>=20
> Regards,
> ZmnSCPxj
If the users are expected to manually operate a hardware wallet to fund =
the channel, they might do stupid things like using 2 wallets to make 2 =
txs, thinking that they could combine the values this way; or =
=E2=80=9Crefilling=E2=80=9D the offchain wallet with the address, as you =
suggested. While I appreciate the goal to separate the coin-selecting =
wallet with the offchain wallet, I am not sure if we should rely on =
users to do critical steps like entering the right value or not reusing =
the address. Especially, the setup address should be hidden from =
user=E2=80=99s view, so only a very few =E2=80=9Cintelligent advanced =
users" could try to refill the channel.
If we don=E2=80=99t rely on the user as the bridge between the hardware =
wallet and the offchain wallet, we need a communication protocol between =
them. With such protocol, there is no need to spend the setup TXO with =
NOINPUT.=
|