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Maybe I'm being too much of a Spok here,@shadders , but this sentence's semantics beg for a question: "SPV Channels CE (for “community edition”) allows asynchronous encrypted messaging between participants, even when there’s no direct connection between them (e.g. one may be offline)." Does "direct cxn between them" mean: 1) The wallets can talk to each other, via something like NFC phone-to-phone, but niether can talk to the internet (no WIFI or LTE)? 2) One wallet can access the internet while the other cannot? 3) The two wallets cannot talk via NFC, but one of them has internet access? 4) Other? Seems like if both wallets are SPV and using NFC, and niether has internet connection, money can STILL be confidently exchanged so long as the receiver trusts his SPV verfication and the inputs are sufficiently deep from the blockchain tip, no? But to do this, the sender would need to send the merkel branch hashes of the inputs, along with the transaction, yes? source: https://coingeek.com/true-p2p-and-spv-released-on-bitcoin/

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venezia tipped:

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2 years ago

electrumsv

SPV channels is a service-based mailbox. So if you are offline, someone can send you a message. That's it. -- rt12

john replied:

Is it not good enough if I send you a payment along with the inputs' merkel branches? Then you could compute the merkel branches to see if they compute to the Merkel root which your wallet has stored (all of them), and at LEAST you'd know that I sent you something logical. Or would you be worried that I pre-copied some branches on old transaction inputs? I still have to SIGN, so I would think zero-internet (for both sender and reciever) would be possible, so long as each person began storing the merkel-branches of all of their UTXOs. I understand that if the merchant has an internet connection, they can send a request for merkel-branches to any inputs I send him in a transaction, thus confirming using an actual Node (even if I the customer don't have an internet cxn). Cases where merchant has internet cxn and user doesn't, are increasingly rare. Like Antartica? Even they probably have LTE.

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electrumsv replied:

I think you've assumed meaning that is not there. Everyone is not online all the time, and even if they are you cannot connect to them wherever they are. That's it. -- rt12

adonsats replied:

" Cases where merchant has internet cxn and user doesn't, are increasingly rare" NO it is not. think about it a bit more. Again, it is not.

“Increasingly rare” is appropriate. If not, pls state some classes of cases otherwise.

Electrum, I’m referring to NFC connections which are possible without internet connections by either party. The question remains— can a reciever do a merkel proof using just block headers stored on-device plus merkel branches of txn inputs provided by sender? The question basically amounts to: can a receiver trust merkel branch “proof” provided by the sender himself.

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