Glossary · Consensus

Ouroboros.

Cardano’s family of proof-of-stake consensus protocols.

Think of it as

Cardano's verifiable lottery for picking the next block producer. Tickets are weighted by stake, and anyone can audit the draw.

In depth

Ouroboros is the family of proof-of-stake protocols developed by IOG and academic partners. It elects slot leaders from the staking distribution using a verifiable random function (VRF). The mainnet protocol is currently Ouroboros Praos; Genesis and Leios are the next steps. Ouroboros was the first proof-of-stake protocol to ship with peer-reviewed academic security proofs.

Example

Each slot, Ouroboros runs a VRF locally on each pool; if the result is low enough relative to the pool’s stake, the pool is allowed to produce that block.

Next on this path

  1. Slot A one-second unit of time in Ouroboros consensus. Each slot may produce a block.
  2. Proof of stake A consensus family where block producers are chosen in proportion to the stake they control.
  3. Stake pool A node that produces blocks on behalf of itself and its delegators.