I really want to like these storage-coin ideas, but it seems like the obvious advance needed is a conceptual way to distribute the blockchain so each individual computer doesn't have to hold all of the data, and (hand-in-hand) to eventually allow data to be removed from the chain. I don't understand how they can otherwise be sustainable long-term. It also seems like they could take some lessons from BitTorrent, where peers get credit for transferring data rather than computations.
I'd be much more interested in a blockchain designed to secure other sources of data than one that attempts to store data itself (NMC or DTC). Hashes and signatures of important files, personal and corporate public keys, etc.
You can put file hashes in Datacoin, no? If we made a coin that only allowed storing hashes, folks could just encoded their data to make it look like hashes.
Unless...we could build a system that would allow storing of hashes but only after somehow verifying that the submitter actually possessed data of a nontrivial size which produced that hash value. So maybe a little less like regular hashing and a little more like public-key encryption? Just a thought.
Well, obviously you could never entirely prevent abuse (as bitcoin shows), only make it costly. Low fixed limits on storage size would at least keep people from throwing an avi in most of the time.
I think maybe hashes wouldn't make much sense, though, anyways. If you were say ubuntu and you wanted to make your releases verifiable through the blockchain you'd just put a public key in under ubuntu.releases and it'd be the signature of the file matching that would matter.
When it comes right down to it I guess I basically want a namespaced, blockchain-verified, pgp. With maybe more flexibility about key types so you could throw things like ssh keys or bitcoin addresses or such in. Or maybe dnscurve/dnssec keys.
And yeah, you could use either namecoin or datacoin to do this, but I think they're trying to be too much and that will be a problem. Could you imagine how big a block chain that contained the entirety of dns as it exists now would be? There's a reason the internet moved from distributing a hosts file to everyone.
It's already the case with bitcoin that each computer does not need to hold all of the data. You're just not running a full node at that point. Which makes sense.
That may be right given a certain definition of "full node," but without all the data, you cannot validate transactions all the way back.
In other words, you really only "need" to know all the unspent outputs; those are the only bitcoins that can be spent validly. But how do you _know_ that your list of unspent outputs is correct? You would only know by validating all the way back to the beginning of the blockchain. Otherwise, you are going off "trust" at some point in the past.
You may know a lot more than I do, so fill me in if I'm missing something here.
> But how do you _know_ that your list of unspent outputs is correct?
Because you calculated it. For full security you need to witness the entire block chain, but as soon as you've validated a block and processed its transactions into the unspent transaction output set, you can throw it away. You know the UTXO set is valid because you trust your past self to have calculated it correctly (and if you negate that assumption then you quickly end up not able to trust anything at all).
This isn't even considering UTXO commitment schemes which let you retrieve from the network UTXO data with SPV level of security, or to validate from the genesis block while storing nothing, not even the UTXO set.
FWIW, "full node" is usually taken as shorthand for "fully validating node" which doesn't necessarily require storage of block chain data, whereas "archive node" indicates a node that does keep full block chain history.
this is likely under development and will be built on top of the original DTC block chain. See "personal chains" on the DTC website. It's hush hush right now because early adopters want the price to stay low so they can buy as many DTC as possible until this new development is released, when the price will skyrocket
