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The consensus protocol for Cardano. Ouroboros ensures that all participants agree on valid transactions. It is the first consensus protocol proven to be secure through academic peer review. The name comes from an ancient symbol that represents eternity and symbolizes the theoretical eternity of a blockchain. There have been several versions of Ouroboros: Classic (Byron phase, 2017), BFT (Byron/Shelley phases, 2020), Praos (Shelley phase, 2020), Genesis (planned for 2023), Chronos (in planning), Crypsinous (no deployment planned for Cardano).