Den 8 jan 2015 11:54 skrev "realcr" <rea...@gmail.com>: > > Hey, thanks again for the reply. >> >> The only notable difference is that in my version you are checkpointing the change in th blockchain. >> >> You still have the very same form of signing, but you sign a slightly different message (transfer of a colored coin, one Satoshi worth of Bitcoin, to a new address) instead of "group members XYZ are now the official group instead of ABC". > > > I disagree with you, or maybe I have misunderstood you idea. I think that Bitcoin is not related here. > > Bitcoin is all or nothing. If I want to use it, all the participants of the network have to be part of it. > That means that all the participants of the network have to compute hashes all the time. > In addition, every Bitcoin transaction involves all the participants of the network.
I think you overestimate the impact of using Bitcoin. It isn't all our nothing as not all members need to be full nodes, in fact none of them have to be. While it is true that all full nodes must store all the transactions, and that it gets forwarded in the network among most online nodes as it gets published, only the latest one would need to be kept in their index of the unspent outputs (UTXO set) from the blockchain. The Bitcoin developers is constantly working on scalability, and the network is meant to one day be able to handle thousands of transactions per second (this is years off, though). The blockchain can easily be stored on MicroSD cards! Verifying the headers alone for decades worth of hashes takes at most minutes on smartphones. And that's a one-time job per header hash, per device. Each new header takes much less than a second to process. Publishing and verifying the colored coin transactions is trivial too. > Secrecy is not required. I meant to say that the band has the responsibility of keeping the signatures and show them on demand. You still don't get any meaningful security if old band members are assumed to be untrusted and you don't use a public checkpointing mechanism. Transfer of the title of being the real group must be a one-time only thing for each version of the group, and must be impossible to backtrack from. Bitcoin enforces this by design. Other standard public checkpointing mechanisms don't verify if there's conflicting messages or not, so then ALL messages that has been checkpointed must be stored. There are cryptocurrencies with similar functionality (doublespend protection, conflicting assignments not allowed) and other trust models (no proof-of-work for chain selection). As an example, Ripple is federated, a set of trusted nodes agree on the order of transactions. This removes most of your performance related issues. But I don't trust it if security is important, it seems too ad-hoc. Then there's proof-of-stake which is very problematic for a million different reasons (no guarantee there will be concensus), but the network performance issues from Bitcoin remains here.
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