Plan can’t solve for trilemma---would have to make new business rules

With blockchain becoming so popular, and with everybody trying to build the decentralized applications which will turn the technology mainstream, there are still many challenges for public blockchains, aside from the fact that the blockchain should be integrated in the current legacy centralized system. The challenges of the public blockchains are related to Scalability, Interoperability and Sustainability, coined in 2018 as the blockchain trilemma by Vitalik Buterin, the creator of Ethereum, referring to the difficulty of creating a blockchain with the three characteristics at the same time (Ethereum, 2018). Currently, there is no fully working blockchain to have solved all these issues and it is considered that you can only address two of them by giving up the other one (Lyons et al., 2019). That is why multiple blockchain platforms exist: to offer the best possible solutions for specific use-cases. In what follows, we are going to talk about these three challenges, while later on we are going to see possible solutions to them. 3.1. Scalability

A public blockchain should respond to the critical challenge of scalability, which means to achieve the consensus of the distributed computing nodes in a scalable and efficient manner. In the blockchain, all the nodes are involved in creating blocks that can be added to the ledger and they decide whatever unconfirmed transactions they want to include in the block they are working on. The node which calculates the first valid hash in PoW or the declared leader in PoS or other consensus mechanisms is going to forge the new block and then the block needs to be broadcasted to the whole network. A new block of 1MB for Bitcoin is propagated every 10 minutes, giving it a throughput of 7 transactions per second (tps), while Ethereum can confirm 20 tps (Lyons et al., 2019). Small adjustments have been brought to the blockchain in order to address scalability issues, such as increasing the block size of Bitcoin, which is 1MB, to 4 or 8MB. A hard fork in the main Bitcoin blockchain has been created, called Bitcoin Cash, having an 8MB block (Bashir, 2018). While this adjustment can increase the number of transactions that can be stored on a block, the block will take longer to propagate in the network, as nodes require better internet connection with larger bandwidth. In the case of maintaining the size of the blocks, transactions with higher fees are validated faster, as miners have the ability to choose the transactions they want to mine, in order to gain higher rewards. This will unfairly cause the neglect of low fee value transactions, as the blockchain might not follow a first come first served rule. A solution for scalability is the SegWit (Segregated Witnesses), another fork in the Bitcoin, which eliminates different signatures from the blocks, thus allowing the addition of more transactions (Bashir, 2018). To gain a better performance in scaling the blockchain, research has been conducted to address the problem by creating new data structures, such as Directed Acyclic Graphs (DAGs), or more efficient consensus algorithms, or to move transactions and computations from the blockchain to a second-layer protocol. While looking for solutions for replacing the computation puzzles in PoW with more useful ones, many blockchains are trying to replace PoW with PoS, or to integrate PoS with PoW. The Ethereum team has been talking about replacing PoW with PoS since 2014, and wanted to replace Ethash with Casper protocol, which we currently see integrated in Ethereum 2.0 (Serenity), an early version of Ethereum, built from scratch, using the PoS. For this new version of Ethereum, Vitalik Buterin states that it will validate transactions with 1% of the energy consumed by PoW (Zamfir, 2016). 3.2. Interoperability With the persisting problems of scalability and the variety of approaches to solve them, the market has got up to more than 2700 cryptocurrencies in September 2019 (CoinLore, 2019). The problem raised is that, with so many different implementations, and with many of them having their own adopters, blockchains will have to be able to share information with each other. This means that transactions could span multiple blockchains and information on a blockchain could be retrieved and validated through a transaction on another blockchain (Yaga et al., 2018). In Hardjono et al. (2018), Hardjono et al. talks about what blockchains should look like in order to achieve interoperability, referring to the main goals of the Internet architecture and how they should be applied on the blockchain. One of the examples built with the Internet architecture goals premise is MIT Tradecoin. Another project proposes the Digital Trade Coin (Lipton et al., 2018), a cryptocurrency to replace cash money with a worldwide stable digital token, serving as a “blueprint” for an interoperability model between blockchains. 3.3. Sustainability Sustainability refers to the ability of public blockchains to remain a viable solution over time. A blockchain has to be environmentally friendly, efficient, while its entities should be able to govern over the blockchain in a decentralized manner, in order to take actions in case unlawful acts are being committed (Lyons et al., 2019). As blockchains are mostly open-source and maintained by communities of programmers and advisors, in order to be successful and sustainable, Decentralized Autonomous Organizations (DAOs) or Decentralized Organizations (DOs) can integrate the ways in which a blockchain should be maintained and governed, keeping the blockchain upto-date, secured and running for the good of the system. Many of the current blockchain projects are implemented by companies and corporations that make the decentralized public blockchain mostly centralized, due to the fact that these companies are deciding the roadmaps of the implementations. Blockchain protocols are actively improved and nodes have always been incentivized to participate in the consensus, but the community and developers have been trying to find ways to improve the system in their own time. New business rules need to be applied to decentralize companies and corporations and also to govern a blockchain like Bitcoin, to reward the individuals proposing enhancements and developing them towards improving the system. A DAO can dictate the economy that incentivizes community participation, which can speed up the implementation of new technology.