Hyperchains offer the promise of a novel way to create a hybrid chain that leverages the security of very large PoW networks with a much less energy-intensive PoS consensus algorithm. From the Hyperchains whitepaper:
Blockchains rely on decentralized consensus between miners. Several ways of achieving it in a safe, provable, and fair manner have emerged. The oldest approach dating back to Satoshi Nakamoto’s whitepaper, known as Proof of Work (PoW) implemented in several cryptocurrencies is extremely expensive and leads to ridiculous energy waste. Cheaper algorithms based on Proof of Stake (PoS) promise similar security to PoW, but are usually prone to exploitation. We propose a novel hybrid between PoW and PoS based on BitcoinNG, which combines advantages of both without acquiring their drawbacks.
We’ve spent a lot of time developing and polishing the idea. The goal is to make the protocol rock solid and while doing this we’ve found and fixed some weaknesses of the intial design. That’s why we have not yet published the final Whitepaper - it is constantly evolving. This is how the concepts of Proof of Fraud and Proof of Laziness were created and further expanded. It is obvious that that this process of RnD can take some time. Since we want to be open to the community we will share with you both the difficulties we are facing and our strategy for solving them.
The difficulties revolve around the following subjects:
- Attack vectors that exploit the finite and mappable nature of network nodes participating in the staking pool
- Ways to induce imbalances in the distribution of stake by DoS attacks against individual stakers
- Proof-of-laziness exploits (a rather sticky problem!)
- The best recovery strategy for a compromised pool of stakers
- Distinguishing between malicious (punishable) misbehavior and accidental (unpunishable) missed-behavior
- Balancing punishiments and economic incentives
All of those are on top of our continuous effort for improvement both of the protocol and the implementation of the node itself. That’s why we are planning the following:
- Expand the team with some great talents. This will allow us to keep developing the HC without compromising the protocol development and the node improvements. Bear in mind we also support the AeCanary so the more hands we get, the better. We are already in talks with some great people out there.
- Split the HyperChains development into steps with clearly defined deliverables so we can test our assumptions and build incrementally on top of that. The first step would be a permissioned HyperChain - stakers are set in the protocol contract. This will disable most of the attack vectors but will also provide us with an initial implementation of HCs. We call that HyperChains Alpha.
- Continue the effort of improving the permissionless HC concept and explain it in a Whitepaper document.
Note that all three bullets are orthogonal and we will be running them in parallel. Once we get to HC Alpha we can initiate development of tools for staking and exploring a HC network.
Aeternity has a powerful set of features and operational properties that make it much more practical for use as an actual currency in commercial transactions than any other blockchain that we have so far assessed. Aeternity has low latency confirmations and high transaction rates based on Bitcoin-NG, a gas valuation system that is tunable to ensure that both miners and transaction issuers are positively incentivised to play by the rules, state channels with fast transactions between two parties, and even ongoing work on HTLC based state channels and multi-party signature schemes that eliminate both the data burden and mempool overhead to the main chain incurred by a heavy transaction load. In fact, with state channels the thus far unrealized promises that contract-based distributed applications originally offered the blockchain world can be realized in a remarkably lightweight way. A permissioned HyperChain would be a great step towards expanding the capabilities and use cases of the Aeternity blockchain.
We will keep you informed with our progress.
… looking forward to play around with the initial Hyperchains Alpha implementation 
