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Enter the Hydra: scaling distributed ledgers, the evidence-based way

Learn about Hydra: the multi-headed ledger protocol

26 March 2020 Prof Aggelos Kiayias 10 mins read

Enter the Hydra: scaling distributed ledgers, the evidence-based way

Scalability is the greatest challenge to blockchain adoption. By applying a principled, evidence-based approach, we have arrived at a solution for Cardano and networks similar to it: Hydra. Hydra is the culmination of extensive research, and a decisive step in enabling decentralized networks to securely scale to global requirements.

What is scalability and how do we measure it?

Scaling a distributed ledger system refers to the capability of providing high transaction throughput, low latency, and minimal storage per node. These properties have been repeatedly touted as critical for the successful deployment of blockchain protocols as part of real-world systems. In terms of throughput, the VISA network reportedly handles an average of 1,736 payment transactions per second (TPS) with the capability of handling up to 24,000 TPS and is frequently used as a baseline comparison. Transaction…

Stake pools in Cardano

IOHK’s chief scientist introduces staking

23 October 2018 Prof Aggelos Kiayias 17 mins read

Stake pools in Cardano

In a proof of stake (PoS) blockchain protocol, the ledger is maintained by the stakeholders that hold assets in that ledger. This allows PoS blockchains to use less energy compared with proof of work (PoW) or other types of blockchain protocols. Nevertheless, this requirement imposes a burden on stakeholders. It requires a good number of them to be online and maintain…

How does Casper compare to Ouroboros?

Differences between the proposed Ethereum protocols and Cardano’s consensus algorithm

9 August 2018 Prof Aggelos Kiayias 13 mins read

How does Casper compare to Ouroboros?

TL;DR In response to recent discussions in social media, we give a brief comparison of the Ouroboros and Casper proof-of-stake protocols.

Ouroboros is a formally specified and analysed protocol with mathematically proven security guarantees based on clearly specified assumptions. The protocol description, models and proofs are all public. Hence, the underlying assumptions, the…

On the Ouroboros Design: How rigour and engineering are essential for critical infrastructure

11 January 2018 Prof Aggelos Kiayias 7 mins read

On the Ouroboros Design- How rigour and

A blog post on the Steemit website appeared recently making a number of claims regarding Ouroboros. The article contains several factual inaccuracies. For instance, it is claimed that “DPOS” in the Ouroboros paper stands for “delegated proof of stake”, while in fact, DPOS means “dynamic proof of stake”, or that the protocol requires a "2/3+" ratio of parties being honest, while…