Re: [Bitcoin-development] Simple contacts exchange (was: Social network integration (brainstorm))

[Mike Hearn <mike@plan99.net>]

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You can prove ownership of a private key by signing a challenger-generated
nonce with the public part and giving the signature back to the challenger
- same as with any asymmetric crypto system.

As I already noted, the payment protocol is designed to solve that problem.
You could design a BIP that extended the payment protocol to include
information about the person who generated it.


On Tue, Sep 17, 2013 at 11:30 AM, Wendell <w@grabhive.com> wrote:

> Couple of things I just thought about:
>
> 1- Presume server should only sweep with two (or more, see below)
> revocation certificates being present
> 2- Need to insert something in the flow so that Alice can verify that the
> uploaded key is actually Bob's (and perhaps vise-versa, given an extremely
> dedicated attacker with a fast connection?).
>
> Is there a way to do #2 without creating yet another transaction?
> Admittedly I am still really puzzled about the accessibility of public keys
> in Bitcoin!
>
> Please remember that the idea is to have two wallets securely exchange a
> packet of metadata about a transaction beyond the scope of Bitcoin itself
> (a name, perhaps a small photo, etc) in order to increase usability. This
> will be my last post here on the topic except to reply in case anyone else
> contributes.
>
> -wendell
>
> grabhive.com | twitter.com/grabhive | gpg: 6C0C9411
>
> On Sep 16, 2013, at 4:05 PM, Wendell wrote:
>
> > Luke pointed out that we should not be inserting extraneous data into
> the blockchain, so this sounds like the best option, Eric.
> >
> > I'm under the impression that a Bitcoin user Alice cannot see the actual
> public key of Bitcoin user Bob, so if we had Hive store metadata on a
> server relating to a given transaction ID, I would not be able to use those
> public keys key to encrypt. Is this a misunderstanding or is it correct?
> >
> > Assuming it is correct, the best that I could come up with was storing
> the transaction ID with a _fresh_ public key on a server, each time a
> transfer is made. Altogether it looks like this:
> >
> > - Alice generates a new keypair & revocation certificate for the
> transaction
> > - Alice makes a Bitcoin transaction to Bob
> > - Alice sends the transaction ID plus the new public key to server
> > - Bob receives the Bitcoin transaction
> > - Bob generates a new keypair & revocation certificate
> > - Bob does a transaction ID lookup on the server, receives Alice's
> public key, sends his own new one
> > - Bob encrypts his user metadata against Alice's new key
> > - Alice downloads and decrypts Bob's metadata
> > - Alice uploads her revocation certificate
> > - Alice uploads her own metadata
> > - Bob downloads Alice's metadata
> > - Bob uploads his revocation certificate
> > - (Server removes all keys with revocation certificates)
> >
> > I presume going the extra mile to generate new keys for each transaction
> is helpful for privacy?
> >
> > The above seems rather inelegant to me. I really don't like that clients
> (wallets) are going to be beating down the server all the time checking for
> keys, or that there is a possibility of a desynchronization so severe that
> the user receives the data much too late for it to be useful. But, I
> suppose it can work.
> >
> > Another thing I'm considering is Alice/Bob validating each other. I
> suppose we should include some kind of code that we encourage people to
> read to each other over the phone or some other medium, to ensure that "it
> really is Alice", before (for example) returning money to a very
> legit-looking personage.
> >
> > Any other thoughts? I would love to do this without using any servers at
> all ("serverless keyserver", anyone?), but I am not quite sure how.
> >
> > -wendell
> >
> > grabhive.com | twitter.com/grabhive | gpg: 6C0C9411
> >
> > On Sep 7, 2013, at 12:47 AM, Eric Lombrozo wrote:
> >
> >> Why not just use the transaction hash itself for the lookup? Also,
> presumably you'd want to encrypt the data so that only the recipient of the
> transaction can do this lookup.
> >>
> >> -Eric
> >>
> >> On Sep 6, 2013, at 8:07 AM, Wendell <w@grabhive.com> wrote:
> >>
> >>> Hi all,
> >>>
> >>> We're thinking about ways of automatically exchanging contact details
> between wallets, in order to encourage the proliferation of identifiable
> names and photos rather than long and hard-to-verify addresses.
> >>>
> >>> The simplest version goes like this:
> >>>
> >>> 2 BTC Bitcoin is sent to someone, and a data lookup hash is inserted
> into the transaction. When it arrives on the other end, it is indeed looked
> up, and instead of being presented with a dialogue that says "you received
> 2 BTC from 13Y94z43Nbbb6wevRyk82CeDoYQ5S28zmA", it's "You received 2 BTC
> from Frank Jones" including a nice photo.
> >>>
> >>> Now. We can simply delete this data in reference to the transaction ID
> after it happens (or delete it after a time), but is there any more
> decentralized way to do it? I would prefer us to run no dedicated servers
> that would ever put us in a position of being coerced into giving data, or
> otherwise altering our system to store it.
> >>>
> >>> Any thoughts about this?
> >>>
> >>> -wendell
> >>>
> >>> grabhive.com | twitter.com/grabhive | gpg: 6C0C9411
> >>>
> >>>
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