Paper 2021/1705

GoUncle: A Blockchain Of, By, For Modest Computers

Mao Wenbo and Wang Wenxiang

Abstract

GoUncle is a blockchain for permissionless participation by modest computers. As in GHOST (Greedy Heaviest Observed SubTree, successfully implemented by and used in the Ethereum blockchain's Proofs-of-Work version), GoUncle blocks also record public-key identities of some forking blocks' finders who are dearly called ``uncles'' (poorly named ``orphans'' in Bitcoin). While GHOST uses uncles only for saving PoW mining electricity, GoUncle assigns jobs for uncles to do. In a so-called {\em payload screening} job, uncles choose from earlier payloads only data items complying with the blockchain database (DB) policy to announce for the blockchain's gossip protocol to diffuse. Now that the blockchain can readily append blocks containing incorrect payloads, each block's height as a globally known address becomes {\em deterministic} right upon appending the block. The deterministic blockchain addresses can index partition the distributed blockchain DB into small files to store in nowadays low-cost over provisioned external storage, for fast input, output, lookup, insert, update, manage, ..., etc., exactly the same as a standard DB management system (DBMS) is operated. It is that the blockchain DB becomes a standard DBMS for fast operable even by a modest computer, that secures the DBMS by a {\em hop-by-hop firewall} among vast {\em semantics gossipers} who each, upon receipting a gossip of the uncles' screening, looks up its local DBMS and judges to either deposit it in and gossip it on, or discard it. This hop-by-hop firewall works exactly as {\em correctness probability amplification} by repeated execution of a {\em randomized probabilistic} (RP) algorithm, and thus the following becomes newly known: $$\mbox{Blockchains} \subset \mbox{RP}.$$ Also to be manifested is a more general and methodological use of uncles as No-Spam and No-Single-Point-of-Failure (No-SPOF) set of blockchain servers.