Blockchain
Innovative features to bring blockchains to the mainstream and support digital civilisations.
Hooks
Strengthen the security of your blockchain with the hooks checkpoint protocol.
Hooks are forward pointers in a chain, constructed using digital signatures, that are analogous to the (parent block) backward hash pointers. The checkpoints created are tamper-proof records that a given block has been made final, namely, it is an immutable block part of the main chain. This protocol can be modularly added to your blockchain to enhance its security level.
Modular addition of security for blockchains; for instance, quantum resistance.
The ability to identify safety breaks in the finality protocol.
The participant that authors a hook is called a picket. It creates a public cryptographic key that is added to block B. Once a block B’ is made final at a parametrised height after B, the picket creates a digital signature of B’, which is to be placed in the chain. A block C is checkpointed when it has enough hooks supporting it. Hooks can then be used to validate the legitimacy of a chain by examining whether the blocks along this chain have been checkpointed.
Hierarchical Consensus
Optimistic consensus for unbounded scalability and speed.
A byzantine tolerant consensus protocol that relies on an optimistic and a fallback subprotocol. The former is quick to make a decision but may fail to do so, and the latter, which takes over if the former fails to make a decision, is slower but always reaches a decision. The protocol puts in place incentives to encourage the participants of the optimistic subprotocol to come to a quick decision; byzantine participants can delay but not prevent a decision from being made.
Each of our subprotocols relies on a committee of agents selected to agree (i.e. make a decision) on a block. The difference between the optimistic and the fallback is that the former can tolerate a committee with a higher proportion of byzantine agents. Given this realisation, we can use stochastic modelling to demonstrate that the optimistic machine can rely on a much smaller committee of agents and, hence, fewer agents need to cooperate to reach an agreement. The trade-off is that this smaller committee can get to an impasse at which point the fallback mechanism aided by a handover protocol can take over and decide. The handover protocol safely transfers control from the optimistic to the fallback. For instance, if the former has reached a partial decision already, the fallback will simply ratify this decision.
Hierarchical consensus with stochastic modelling brings about unprecedented scalability and speed for blockchain systems.
Random beacon
Robust distributed generation of randomness.
A multiparty-computation protocol that brings together participants to robustly generate random numbers periodically. Such a source of randomness is vital in implementing several algorithms. For instance, many internal blockchain operations, especially in Proof of Stake protocols, use random numbers to select committees.
In the protocol, a committee of agents is selected to contribute a random element to be combined into the random number output by the beacon; they rely on a commit-reveal protocol for that. To prevent agents from refusing to release their elements, we rely on a cryptographic function called delay encryption. The agents are required to (delay) encrypt their random elements such that at the reveal phase of the protocol these values are decrypted and disclosed whether they want it or not.
Reliable and robust distributed generation of random numbers, which can be used as either an internal randomness source for the blockchain or as an external service on the blockchain.