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From: "David A. Harding" <dave@dtrt.org>
To: Tom Trevethan <tom@commerceblock.com>,
	Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Statechain implementations
Date: Tue, 31 Mar 2020 06:35:08 -0400	[thread overview]
Message-ID: <20200331103508.asvxujkhtifj6n7i@ganymede> (raw)
In-Reply-To: <CAJvkSseW9OZ50yQiS7e0zt9tQt4v9aoikgGs_54_kMN-ORkQgw@mail.gmail.com>

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On Wed, Mar 25, 2020 at 01:52:10PM +0000, Tom Trevethan via bitcoin-dev wrote:
> Hi all,
> 
> We are starting to work on an implementation of the statechains concept (
> https://medium.com/@RubenSomsen/statechains-non-custodial-off-chain-bitcoin-transfer-1ae4845a4a39),
>
> [...]
> There are two main modifications we are looking at:
> [...]
> 
> 2. Replacing the 2-of-2 multisig output (paying to statechain entity SE key
> and transitory key) with a single P2(W)PKH output where the public key
> shared between the SE and the current owner. The SE and the current owner
> can then sign with a 2-of-2 ECDSA MPC. 

Dr. Trevethan,

Would you be able to explain how your proposal to use statechains with
2P-ECDSA relates to your patent assigned to nChain Holdings for "Secure
off-chain blockchain transactions"?[1]  

    [1] https://patents.google.com/patent/US20200074464A1

Here are some excerpts from the application that caught my attention in
the context of statechains in general and your proposal to this list in
particular:

> an exchange platform that is trusted to implement and operate the
> transaction protocol, without requiring an on-chain transaction. The
> off-chain transactions enable one computer system to generate multiple
> transactions that are recordable to a blockchain in different
> circumstances
>
> [...]
>
> at least some of the off-chain transactions are valid for recording on
> the blockchain even in the event of a catastrophic failure of the
> exchange (e.g., exchange going permanently off-line or loosing key
> shares).
>
> [...]
>
> there may be provided a computer readable storage medium including a
> two-party elliptic curve digital signature algorithm (two-party ECDSA)
> script comprising computer executable instructions which, when
> executed, configure a processor to perform functions of a two-party
> elliptic curve digital signature algorithm described herein.
>
> [...]
>
> In this instance the malicious actor would then also have to collude
> with a previous owner of the funds to recreate the full key. Because
> an attack requires either the simultaneous theft of both exchange and
> depositor keys or collusion with previous legitimate owners of funds,
> the opportunities for a malicious attacker to compromise the exchange
> platform are limited.

Thank you,

-Dave

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  parent reply	other threads:[~2020-03-31 10:36 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 13:52 [bitcoin-dev] Statechain implementations Tom Trevethan
2020-03-26  1:20 ` ZmnSCPxj
2020-03-26  3:55 ` Albert
2020-03-26 12:36   ` Ruben Somsen
2020-03-26 17:12     ` Christian Decker
2020-03-26 17:17       ` Greg Sanders
2020-03-26 18:53         ` Ruben Somsen
2020-03-27  1:46           ` ZmnSCPxj
2020-03-27 15:12             ` Ruben Somsen
2020-03-28  2:20               ` ZmnSCPxj
2020-03-26 14:52   ` Bob McElrath
2020-03-27 17:10 ` Bob McElrath
2020-03-28  2:42   ` ZmnSCPxj
2020-03-28 17:38     ` Ruben Somsen
2020-03-28 17:42       ` Ruben Somsen
2020-03-30  1:25         ` ZmnSCPxj
2020-03-31 10:35 ` David A. Harding [this message]
2020-03-31 11:41   ` Tom Trevethan
2020-04-02 22:56     ` Tom Trevethan
2020-04-03 16:37       ` Nadav Kohen
2020-04-04 12:07         ` ZmnSCPxj
2020-04-05 14:17         ` Bob McElrath
2020-04-05 18:24           ` ZmnSCPxj
2020-04-05 21:25           ` Tom Trevethan
2020-05-07 14:54             ` Tom Trevethan

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