Okay, we're comparing to the same thing, at least. The Stratum servers can be set to communicate with a full-node that you trust, but many users will either pay a fee to use one, or trust based on majority response from a bunch of free servers. When the latter is used, you can get awfully creative in trying to figure out what servers are telling you the truth, profiling them, blacklisting nodes, etc.
What I don't get is why you scoffed at the necessity of having a connection, but I don't know how the Stratum overlay network you describe can work without a connection...?
I don't think that I'm expressing myself well here. I not 'scoffing' at the idea that some clients need live Interent access in order to function. I'm saying that more than one method to support lightweight clients that require live Internet already exist, and none of them actually require the resource overhead of an alt-chain. Make no mistake, the distributed security of bitcoin is an awesome thing, but it's also expensive in many ways. Murged mining
helps in that regard to a limited degree, but it's a crude kind of hack. Not at all the smooth, elegant & interwoven solution that bitcoin itself is.
What I want is a lightweight client, that can run on my Android phone, and if the cell network is down (snowstorm, Katrina, zombie outbreak, whatever) or I'm deliberately out of my service zone (camping, safari, fishing trip, whatever) my light android client can still transact to some degree sans live Internet. The light client as described in Satoshi's white paper, that holds the block headers & copies of it's own input transactions; can
spend bitcoins because it can create & sign a proper transaction. It can also receive a transaction. What it can't do, without live Internet, is check the validity of a transaction; beyond checking to see if the provided input transactions fit into the Merkle tree. Even with live Interent, an independent light client can't do that nor discover new transactions for itself without scanning whole blocks itself. That's teh role that both Stratum & this proposal seem to fill. If this proposal requires live internet at the time of transaction,
then it offers no practical advantages over Stratum. Stratum is, itself, a distributed p2p netowrk protocol. It may not look like bitcoin, but it doesn't need to either.
You must contact one of the servers in order to construct your outgoing transaction, right?
No, not
must. A client with the block headers, copies of the transactions used to send money to it's own addresses (it's input transactions) and a local wallet.dat can create & sign transctions locally, and it can thus use any of a number of ways to communicate that transction over to the vendor; who then may or may not be able to verify it and may or may not be able to forward that transaction to the Internet immediately. These are not requirements. However, a client that holds only a wallet.dat would need the live support of a Stratum server to construct it's own transaction, so that kind of (ultralight?) client would require live internet.
So why not connect to a alt-chain node and query your address balances the same way? It's slightly more data to download, but it requires zero setup, zero trust, and uses the same networking protocols already used everywhere else (because it's already done in Bitcoin-Qt and the variants used for merged mining nodes).
It's not slightly more to download. It's at least as much with potentially several orders of magnitude more to download, store & verify. There is also the multiplicity issue with blockchains. Bitcoin requires that multiplicity of redundent data, but the light clients do not. That is one of the driving forces for overlay networks such as Stratum, to limit the multiplicity. just because you might not be seeing that across your own data plan, doesn't mean that someone doesn't need to pay for that extra duplication of effort as well. One way or another, the end users are going to be paying for the network.
Again, you can download your entire unspent-TxOut-list from any node with the same confidence as a full node.
I can see that, what I can't see is what gain is there in downloading a regualr digest of a pruned blockchain, when you could just help finish the touches on pruning and do the exact same thing within the bitcoin netowrk, no murged mining hack nor additional network resources required. What you guys are trying to acomplish is already possible within the protocol. Without additional advantages, why bother?
If you don't see it, then you didn't understand the proposal. This is assuming that the second chain is secure, but I'm pretty sure merged mining is taking care of that.
And this is another thing, that is one huge assumption. We didn't know that bitcoin itself would work two years ago. How do you know that murged mining works as described? I sure don't.
As for the spoofing -- people don't need a good a reason to be dicks, they may just want to disrupt stuff. For a "small price" they may be able to disrupt an otherwise useful network, enough that people stop even bothering using it, and accept lower-confidence data. Or just stop using Bitcoin. There doesn't need to be a good reason for it, because anything is a good reason to the person actually doing it.
While dicks will always be dicks, those dicks can't really steal anything of significance, and the high costs of doing what you are talking about is a huge deterrent.
