[Lightning-dev] Collaborated stealing. What happens when the final recipient discloses the pre-image

[René Pickhardt]

Hey Ankit,

The lightning network sees the possession of a preimage as a proof of
payment. And I believe everyone agrees that a court should rule in favor of
A forcing E to deliver the good or reimburse A. The reason is that
possession of the preimage matching the signed payment hash from E is a
much stronger evidence of A actually having paid than E claiming to not
have received anything.
This is also due to the fact that guessing the preimage can practically be
considered impossible (though there is a tiny likelihood)

If E breaches the protocol by giving the preimage to C (for free) instead
of claiming the money from D (and thus settling the Htlc) it will be
considered E's problem, that E did not get reimbursed but just gave out the
preimage for free. (actually E's so called "partner in crime" did get
reimbursed). Even if D would testify that E never settled the Htlc one
would wonder why E never settled the incoming htlc as they should only have
created a payment hash for which they know the preimage. Since A can
actually provide one it is again unlikely if E for example claims they just
used a random hash for which they didn't know the preimage because they
wanted to just see if A has enough liquidity.

With kind regards Rene

Ankit Gangwal <A.Gangwal at tudelft.nl> schrieb am Fr., 17. Juli 2020, 08:43:

> Consider A wants to send some funds to E.
>
>
>
> They don’t have a direct payment channel among them. So, they use a
> following path A-B-C-D-E. A is the sender of payment and E is final
> recipient.
>
>
>
> E sends the hash of a secret r to A, A passes on the hash to B, B to C, C
> to D, and D to E.
>
>
>
> E discloses the secret to C (a partner in crime with E) and E do not
> respond to D. C gives the secret to B (settling the HTLC between them).
> Then, B gives the secret to A (settling the HTLC between them).
>
>
>
> A sent (and lost) the money, as E denies receiving the money (and the
> promised service/good).
>
>
>
> How the lightening network sees this? Out of their control?
>
>
>
> --
>
> A_G
>
>
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