Hi Wendell, What Peter describes (a hash of the current set of UTXOs as part of the coinbase) is already implemented in libcoin, on which you can easily build both a bitcoind and any client. Libcoin is a library originally based on the satoshi client, and as such it is compatible/replacable with "master". Have a look at github.com/libcoin/libcoin and look in the BlockChain.h/cpp and the MerkleTrie classes then you can see how it works. What is missing from libcoin is a scheme to bootstrap the hash of UTXOs, there is some stub code for a p2pool like mining scheme ensuring several UTXO hashes every 10 minutes, but I will not have time to finalize it the first few months - anyone are of course welcome to help out ;) Michael On 17/07/2013, at 09:37, Wendell wrote: > Peter, > > This sounds like a _very_ good idea for a desktop client, and probably acceptable to users so long as we take available disk space into consideration, and only ever use a fraction of it. > > Will you implement this? > > -wendell > > grabhive.com | twitter.com/grabhive > > On Jul 17, 2013, at 12:58 PM, Peter Todd wrote: > >> So what's useful about that? Basically it means your node starts with >> the same security level, and usefulness to the network, as a SPV node. >> But over time you keep downloading blocks as they are created, and with >> whatever bandwidth you have left (out of some user-configurable >> allocation) you download additional blocks going further and further >> back in time. Gradually your UTXO set becomes more complete, and over >> time you can verify a higher and higher % of all valid transactions. >> Eventually your node becomes a full node, but in the meantime it was >> still useful for the user, and still contributed to the network by >> relaying blocks and an increasingly large subset of all transactions. >> (optionally you can store a subset of the chain history too for other >> nodes to bootstrap from) You've also got better security because you >> *are* validating blocks, starting off incompletely, and increasingly >> completely until your finally validating fully. Privacy is improved, for >> both you and others, by mixing your transactions with others and adding >> to the overall anonymity set. >> >> In the future we'll have miners commit a hash of the UTXO set, and that >> gives us even more options to, for instance, have relayed transactions >> include proof that their inputs were valid, allowing all nodes to relay >> them safely. > > ------------------------------------------------------------------------------ > See everything from the browser to the database with AppDynamics > Get end-to-end visibility with application monitoring from AppDynamics > Isolate bottlenecks and diagnose root cause in seconds. > Start your free trial of AppDynamics Pro today! > http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk_______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development