Bitcoin--A-Peer-to-Peer-Electronic-Cash-System

Bitcoin:[e-mail][1],andweneedasystemforparticipantstoagreeonasinglehistoryoftheorderinwhichtheywerereceived.Thepayeeneedsproofthatatthetimeofeachtransaction,themajorityofnodesagreeditwasthefirstreceived.3.TimestampServerThesolutionweproposebeginswithatimestampserver.Atimestampserverworksbytakingahashofablockofitemstobetimestampedandwidelypublishingthehash,suchasinanewspaperorUsenetpost[2-5].Thetimestampprovesthatthedatamusthaveexistedatthetime,obviously,inordertogetintothehash.Eachtimestampincludestheprevioustimestampinitshash,formingachain,witheachadditionaltimestampreinforcingtheonesbeforeit.2BlockItemItem...HashBlockItemItem...HashTransactionOwner1'sPublicKeyOwner0'sSignatureHashTransactionOwner2'sPublicKeyOwner1'sSignatureHashVerifyTransactionOwner3'sPublicKeyOwner2'sSignatureHashVerifyOwner2'sPrivateKeyOwner1'sPrivateKeySignSignOwner3'sPrivateKey4.Proof-of-WorkToimplementadistributedtimestampserveronapeer-to-peerbasis,wewillneedtouseaproof-of-worksystemsimilartoAdamBack'sHashcash[6],ratherthannewspaperorUsenetposts.Theproof-of-workinvolvesscanningforavaluethatwhenhashed,suchaswithSHA-256,thehashbeginswithanumberofzerobits.Theaverageworkrequiredisexponentialinthenumberofzerobitsrequiredandcanbeverifiedbyexecutingasinglehash.Forourtimestampnetwork,weimplementthepr