Using proof of stake for a cryptocurrency is a hotly debated design choice, however because it adds a mechanism to introduce secure voting, has more capacity to scale, and permits more exotic incentive schemes, we decided to embrace it.
Our proof of stake protocol is called Ouroboros and it has been designed by an extremely talented team of cryptographers from five academic institutions2 led by Professor Aggelos Kiayias of the University of Edinburgh. The core innovation it brings beyond being proven secure using a rigorous cryptographic model is a modular and flexible design that allows for the composition of many protocols to enhance functionality.
This modularity allows for features such as delegation, sidechains, subscribable checkpoints, better data structures for light clients, different forms of random number generation and even different synchronization assumptions.
As a network develops from having thousands to millions and even billions of users, the requirements of its consensus algorithm will also change. Thus, it is vital to have enough flexibility to accommodate these changes and thereby future-proof the heart of a cryptocurrency.