Every public consensus based cryptocurrency available today, such as bitcoin and ethereum, offers a blockchain, or a definitive public ledger which is comprised of financial transactions. This consensus based algorithm enables bitcoin transactions from one user to the other, while transactions of ethereum’s blockchain combine financial transactions with database operations which rely on the execution of more complex pieces of computational scripts, known as smart contracts. Cryptocurrency miners, who can freely join and leave the cryptocurency networks, validate these transactions and therefore, determine the owners of each and every coin on the network. Interestingly enough, this verification model does not rely on any central authority to operate efficiently in a secure manner.
Practically speaking, miners can efficiently maintain the integrity of blockchains, provided that the computational burden of transaction validation remains below a certain threshold. In fact, bitcoin and ethereum, whose miners comprise collectively the most powerful collection of computational power in the history of mankind, offer processing power , for verification of transactions, that is no more powerful than a simple smartphone. The volume and complexity of verified transactions’ flow through the blockchain cannot be simply increased without risking inclusion of fraudulent, or invalid, transactions due to a phenomenon known as “Verifier’s Dilemma”, which was manifested in 2015 by the well known “July 4 Bitcoin Fork” while led to chaos across the whole network. In 2016, the Verifier’s Dilemma led to a chain of denial-of-service attacks across the Ethereum network.
A consensus machine permits outsourcing of computation resources to the ethereum network and deliver correct answers in exchange for ether payments, provided that the computational resources provided to offer solutions are below the threshold dictated by the Verifier’s Dilemma. Accordingly, the trustless consensus machine offers a small yet reliable source of semantic truth.
A group of developers recently introduced a novel system that they called “TrueBit” which increases the capabilities of the consensus machine. Theoretically speaking, TrueBit enables smart contracts to perform any computational task in a secure efficient manner. Furthermore, TrueBit markedly reduces the overall number of redundant node computations across the network using ethereum’s traditional smart contracts. Currently, every miner across the ethereum network has to individually replicate smart contract actions, while TrueBit outsources the greater part of the computational work to a myriad of entities. As such, TrueBits offers secure computation outsourcing.
Let’s try to think why cryptocurrencies offer a suitable framework for outsourcing computation securely, which is the main application of TrueBit. Across conventional cloud frameworks, users must confide in the machine software, hardware and cloud administrators that they will work in a secure manner to perform efficiently. Many things can go wrongly, especially the results of such computational processes are tied to monetized scripts such as smart contracts. Proper monetary rewards, the key feature of every cryptocurrency, can prevent a wide range of errors from occurring in a highly efficient manner. Moreover, apart from a cloud whose configuration specifications may not be known to its users, any errors occurring on the network on a blockchain based platform like TrueBit would be visible to the whole community. Cryptocurrencies represent an ideal starting point as they convey a group of beneficial properties:
1. As is the case with the ethereum consensus machine, Nakamoto’s public consensus enables networks to perform small computation processes trustlessly in a correct manner.
2. Blockchains’ public ledgers provide ideal immutability and transparency. Ethereum’s smart contracts inherently provide these features.
3. Cryptocurrency incentives which are directly related to computational processes, can be tempting and help in recruiting participants.
TrueBit and Golem:
TrueBit is not the first project to implement computationally intensive smart contracts, as the Golem project already exists and is centered on outsourced computation. The Golem Project, which has crowdfunded 820,000 Ethereum in November, 2016 (equal to around $8.6 million back then) will utilize TrueBit as the verification algorithm for their soon to be launched outsourced computation networks. TrueBit can support a myriad of applications including:
1. Outsourced computation: TrueBit will be a form of a global computation outsourcing market.
2. Fully decentralized mining: centralized cryptocurrency mining pools can impose some security threats. For any public consensus based cryptocurrency, TrueBit can be used to formulate an efficient, trustless mining pool that is managed via Ethereum’s smart contracts.
3. Trustless cryptocurrency exchange: users now should use central exchanges to exchange cryptocurrencies, or messages, across various blockchains. TrueBit can aid in secure exchange, for example, of Ripple to ethereum.