Toward Self-stabilizing Blockchain, Reconstructing Totally Erased Blockchain (Preliminary Version)

Abstract

Blockchains, that are essentially distributed public ledgers, are extremely popular nowadays and are being used for many applications. One of the more common uses is for crypto-currencies, where they serve as a structure to store all the transactions publicly, securely, and hopefully irreversibly. Blockchains can be permissionless, where everyone can join and potentially contribute the blockchain, and permissioned, where only a few members (usually, much less than a permissionless blockchain) can push new transactions to the chain. While both approaches have their advantages and disadvantages, we will focus on a weakness of permissioned blockchains. The known boundary on the number of faulty participants − up to f for$$3f+1$$ participants − may be surpassed, causing the BFT algorithm to fail. A situation where a malicious adversary compromises/corrupts enough nodes to harm the blockchain may lead to the complete corruption of the ledger and even to the destruction of ledger copies the nodes hold. We will suggest a solution for the reconstruction of the blockchain in the event of such an attack. Our solution will include a mandatory publication of additional information by the private users when submitting transactions and will require them to store their transaction history. We will present a technique, using verifiable secret sharing (VSS), that will make our solution trust-less, immediate and per-user independent. Our technique will prevent the private user from lying, by making such an act enable the possible exposure of the user’s secret key.