From: Stefan Richter <richter@cs•rwth-aachen.de>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Storm: escrowed storage and messaging at L2/L3
Date: Wed, 21 Aug 2019 11:33:24 +0200 [thread overview]
Message-ID: <CAH+=Z+U8sGRtK7TwkGjAQ3yL4WYYnJMJjz9pm+9SOSrHReoerg@mail.gmail.com> (raw)
In-Reply-To: <x1b18QXzxALwxxp8ehwcB7XORizrw5vOJ9BNXWpXbd2SJgUra-AFIyTgnM_yxKEtCg_frZcz916NLmm-pTsCD4Z7aOFprdQ_W87mHnn8vYg=@protonmail.com>
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Please see the github issues and the twitter discussion (e.g. here:
https://twitter.com/stefanwouldgo/status/1163801056423403520) for similar
points other people including me have made. At this point I feel there are
quite a few unclear points in the presentation and it is not clear to me if
they can be salvaged.
Am Mi., 21. Aug. 2019 um 09:32 Uhr schrieb ZmnSCPxj via bitcoin-dev <
bitcoin-dev@lists•linuxfoundation.org>:
> Good morning Maxim,
>
> The Deaf Bob Attack
> ===================
>
> It seems to me that Bob can promote the N3 problem to the N2 problem.
>
> Suppose Alice contacts Bob to get the data.
> However, Bob happens to have lost the data in a tragic boating accident.
>
> Now, supposedly what Alice does in this case would be to broadcast the
> HTLC settlement transaction, whose signature was provided by Bob during
> protocol setup.
>
> But this seems unworkable.
>
> * If Bob managed to sign the HTLC settlement transaction, what `SIGHASH`
> flags did Bob sign with?
> * If it was `SIGHASH_ALL` or `SIGHASH_SINGLE`, then Bob already selected
> the decryption key at setup time.
> * If it was `SIGHASH_NONE`, then Alice could put any SCRIPT, including
> `<Alice> OP_CHECKSIG`.
>
> If Bob already selected the decryption key at setup time, then Bob can
> ignore Alice.
>
> * If Alice does not publish the HTLC settlement transaction, then Bob will
> eventually enter the N2 state and get the stake+reward.
> * If Alice *does* publish the HTLC settlement transaction, without Bob
> giving the encrypted data, then Bob can just use the hashlock and reveal
> the decryption key.
> * The decryption key is useless without the encrypted data!
>
> It seems this part is not workable?
> As the decryption key is embedded in the HTLC, Alice cannot get a
> signature from Bob without the decryption key already being selected by Bob
> (and thus already claimable even without any data being returned by Bob).
>
>
> Regards,
> ZmnSCPxj
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists•linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
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next prev parent reply other threads:[~2019-08-21 9:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 22:08 Dr Maxim Orlovsky
2019-08-21 4:14 ` ZmnSCPxj
2019-08-21 7:32 ` ZmnSCPxj
2019-08-21 9:33 ` Stefan Richter [this message]
2019-08-21 17:04 ` Dr Maxim Orlovsky
2019-08-21 10:51 ` Dr Maxim Orlovsky
2019-08-21 12:48 ` ZmnSCPxj
[not found] ` <A733B8A1-2E88-47F4-A6CF-C56C84E8FF9A@pandoracore.com>
2019-08-21 12:12 ` ZmnSCPxj
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