Ouroboros Praos is a consensus algorithm designed for proof-of-stake (PoS) blockchains. It is an evolution of the original Ouroboros protocol and is specifically implemented in the Cardano blockchain.
Developed by IOHK (Input Output Hong Kong), Ouroboros Praos aims to provide a secure and scalable method for achieving consensus in a decentralized network.
Proof-of-Stake Consensus
- Ouroboros Praos is a proof-of-stake (PoS) consensus algorithm. In PoS, validators (participants who create new blocks and validate transactions) are chosen to create blocks according to the number of cryptocurrencies they own. They are prepared to “stake” as security.
Time-Based Slot Leader Election
- Ouroboros Praos uses a time-based slot leader election system. Validators are chosen to create blocks in specific time slots, with the likelihood of being selected proportional to their stake.
Stochastic Slot Leaders
- The selection of slot leaders is stochastic, meaning that even a stakeholder with a relatively small amount of cryptocurrency can be selected as a slot leader.
Security through Coin Flipping
- Ouroboros Praos introduces “coin flipping” to select slot leaders. This cryptographic protocol ensures that even if a malicious entity controls a portion of the stake, it cannot fully predict or control the selection process.
Security Against Long-Range Attacks
- Ouroboros Praos is designed to provide security against long-range attacks. In a long-range attack, an adversary tries to create an alternative blockchain starting from an earlier point in the chain’s history. Ouroboros Praos introduces cryptographic techniques to mitigate this type of attack.
Adaptive Security
- The protocol offers adaptive security, meaning it can adjust its security parameters over time to address emerging threats or changes in the network environment.
Scalability
- Ouroboros Praos is designed to be scalable, allowing the blockchain to handle many transactions and participants while maintaining efficiency and security.
Cardano Implementation
- Ouroboros Praos is a fundamental part of the Cardano blockchain, a third-generation blockchain platform providing a secure and scalable setting for DApps and smart contracts.
Ongoing Research and Development
- Developing Ouroboros and its variants, including Praos, is an ongoing process. Researchers and developers continuously work to improve the protocol, address potential vulnerabilities, and enhance the overall performance and security of the Cardano blockchain.
Decentralization and Sustainability
- Ouroboros Praos aligns with Cardano’s vision for achieving a decentralized and sustainable blockchain ecosystem. The protocol aims to ensure fair participation in block creation and maintain network security.