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charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Proof of Nodework (PoNW) is a way to reward individual nodes for keeping a = full copy of and verifying the blockchain. Hopefully they also do useful =91traditional=92 node activities too like re= lay transactions and blocks, but there isn=92t really any way I can think o= f to trustlessly verify this also. PoNW would require a new separate area of block space, a nodeblock, purely = concerned with administering the system. A nodeblock is committed to a bloc= k as with SegWit. A recent history of nodeblocks needs to be stored by node= s, however the data eventually becomes obsolete and so does not need to be = retained forever. In order to prevent Sybil, a node must register an Bitcoin address by submi= tting an addNode transaction - along with a security deposit to prevent che= ating. This transaction will be stored in the nodeblock. Once a node can see that = its addNode transaction has been added it can begin the PoNW process. The n= ode=92s registered address will be hashed with the block header of the bloc= k it wants to work on. This will determine exactly where within the blockch= ain to begin the PoNW. The PoNW method could be as simple as creating a Merkle tree from the rando= mly generated point on the blockchain, though a method that is CPU/Memory h= eavy and less likely to be replaced by dedicated hardware like ASICs would = be better. This process could not begin until the most recent block has bee= n fully verified, and while being carried out should still enable normal re= lay activities to proceed as normal, since it shouldn=92t tie up network at= all. The data processed should also be mixed with data from the latest blo= ck so that it cannot be computed in advance. A node can do as much PoNW for a block as it likes. Once finished it will t= hen create a nodeWorkComplete transaction for that block with its final pro= of value, add how much =91work=92 it did - and create a couple of assertion= s about what it processed (such as there were x number of pieces of data ma= tching a particular value during calculating). These assertions can be accu= rate or inaccurate. The system will run in epochs. During each epoch of say 2016 blocks, there = will be an extended window for PoNW transactions to be added to nodeblocks = to limit minor censorship. The random hash generated from a node=92s address and blockhash will also b= e used to determine nodeWorkComplete transactions from a previous block tha= t the node must also verify, and correctly calculate whether the assertions= it made were true or false. The average PoNW that a node performed in its = previous x nodeblocks will be used to determine the target PoNW for the nod= e to verify - and this will randomly be a large number of smaller PoNW tran= sactions, or a smaller number of large PoNW. This process will be determini= stic based on that block and address hash. All the data will be put togethe= r in a transaction and then signed by the node addresses private key. If a nodeWorkComplete transaction contains any incorrect information in an = attempt to cheat the validation process a challenge transaction can be crea= ted. This begins a refereeing process where other nodes check the challenge= and vote whether it is to be upheld or not. The losing node is punished by= losing their accrued PoNW for that epoch and a percentage of their securit= y deposit. Nodes will also be punished if they broadcast more than one signed transact= ion per block. In order to prevent nodes from having multiple keys registered - which woul= d enable them choose to perform PoNW on a subset of the data that they hold= - the share of reward that the node gets will be multiplied based on the n= umber of blocks within an epoch that the node performs PoNW on. The share o= f reward is limited based on how much security deposit has been staked. The= higher the PoNW the higher the deposit needed in order to claim their full= allocation of any reward. At the end of an epoch, with a wait period for any delayed or censored tran= sactions or challenges to be included and settled up, the process of calcul= ating the reward each node is due can begin. This will then be then paid in= a regular block, and means for all the data involved in PoNW, the only per= manent mark it makes on the main blockchain is for a transaction that pays = all addresses their share of the reward at the end of epoch. Any miner who = creates a block without correctly calculating and paying the due reward wil= l have mined an invalid block and be orphaned. The question of where and how much the reward comes from is a different one= . It could come from the existing miner reward, or a special new tx donatio= n fee for nodes. If there was some way for users to =91donate=92 to the rew= ard pool for nodes this would increase the incentive for additional nodes t= o participate on the network in the event of centralisation. This is a relatively effective way to create a reward for all nodes partici= pating on a network. I=92d be keen to field any questions or critiques. Thanks, John Hardy john@seebitcoin.com --_000_BL2PR03MB435AA04A0AB8AC0E7781CA7EE430BL2PR03MB435namprd_ Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable

Proof of Nodewor= k (PoNW) is a way to reward individual nodes for keeping a full copy of and verifying the blockchain.


Hopefully they a= lso do useful =91traditional=92 node activities too like relay transactions and blocks, but there isn=92t really any way I= can think of to trustlessly verify this also.


PoNW would requi= re a new separate area of block space, a nodeblock, purely concerned with administering the system. A nodeblock i= s committed to a block as with SegWit. A recent history of nodeblocks needs= to be stored by nodes, however the data eventually becomes obsolete and so= does not need to be retained forever.


In order to prev= ent Sybil, a node must register an Bitcoin address by submitting an addNode transaction - along with a security depos= it to prevent cheating.


This transaction= will be stored in the nodeblock. Once a node can see that its addNode transaction has been added it can begin th= e PoNW process. The node=92s registered address will be hashed with the blo= ck header of the block it wants to work on. This will determine exactly whe= re within the blockchain to begin the PoNW.


The PoNW method = could be as simple as creating a Merkle tree from the randomly generated point on the blockchain, though a method = that is CPU/Memory heavy and less likely to be replaced by dedicated hardwa= re like ASICs would be better. This process could not begin until the most = recent block has been fully verified, and while being carried out should still enable normal relay activities to= proceed as normal, since it shouldn=92t tie up network at all. The data pr= ocessed should also be mixed with data from the latest block so that it can= not be computed in advance.


A node can do as= much PoNW for a block as it likes. Once finished it will then create a nodeWorkComplete transaction for that block= with its final proof value, add how much =91work=92 it did - and create a = couple of assertions about what it processed (such as there were x number o= f pieces of data matching a particular value during calculating). These assertions can be accurate or inaccurate.=


The system will = run in epochs. During each epoch of say 2016 blocks, there will be an extended window for PoNW transactions to be = added to nodeblocks to limit minor censorship.


The random hash = generated from a node=92s address and blockhash will also be used to determine nodeWorkComplete transactions from a previo= us block that the node must also verify, and correctly calculate whether th= e assertions it made were true or false. The average PoNW that a node perfo= rmed in its previous x nodeblocks will be used to determine the target PoNW for the node to verify - and thi= s will randomly be a large number of smaller PoNW transactions, or a smalle= r number of large PoNW. This process will be deterministic based on that bl= ock and address hash. All the data will be put together in a transaction and then signed by the node addresse= s private key.


If a nodeWorkCom= plete transaction contains any incorrect information in an attempt to cheat the validation process a challenge tran= saction can be created. This begins a refereeing process where other nodes = check the challenge and vote whether it is to be upheld or not. The losing = node is punished by losing their accrued PoNW for that epoch and a percentage of their security deposit.


Nodes will also = be punished if they broadcast more than one signed transaction per block.


In order to prev= ent nodes from having multiple keys registered - which would enable them choose to perform PoNW on a subset of the data t= hat they hold - the share of reward that the node gets will be multiplied b= ased on the number of blocks within an epoch that the node performs PoNW on= . The share of reward is limited based on how much security deposit has been staked. The higher the PoNW th= e higher the deposit needed in order to claim their full allocation of any = reward.


At the end of an= epoch, with a wait period for any delayed or censored transactions or challenges to be included and settled up, the = process of calculating the reward each node is due can begin. This will the= n be then paid in a regular block, and means for all the data involved in P= oNW, the only permanent mark it makes on the main blockchain is for a transaction that pays all addresses = their share of the reward at the end of epoch. Any miner who creates a bloc= k without correctly calculating and paying the due reward will have mined a= n invalid block and be orphaned.


The question of = where and how much the reward comes from is a different one. It could come from the existing miner reward, or a spe= cial new tx donation fee for nodes. If there was some way for users to =91d= onate=92 to the reward pool for nodes this would increase the incentive for= additional nodes to participate on the network in the event of centralisation.


This is a relati= vely effective way to create a reward for all nodes participating on a network. I=92d be keen to field any quest= ions or critiques.


Thanks,


John Hardy

john@seebitcoin.com

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