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Resources

This page provides a collection of resources on Ouroboros Leios, including technical papers, presentations, and videos.

Technical documentation​

Leios CPS​

Summary:​

  • Cardano’s mainnet periodically faces congestion, with block utilization exceeding 90%, delaying transactions and impacting user experience, especially for use cases like airdrops, DEXes, oracles, and DApps. As new applications and bridges (e.g., Cardano-Midnight, Cardano-Bitcoin) increase demand, current throughput (~12 TPS max) lags far behind competitors like Solana (7229 TPS). In Ouroboros Praos, security constraints (e.g., 5-second block relay within a 20-second slot) limit block size and script execution, underutilizing network resources. This CPS calls for research into scaling solutions like Ouroboros Leios to boost transaction volume, size, and execution units, while ensuring predictable processing times for time-sensitive applications. Goals include defining stakeholder needs, safely increasing limits, and leveraging underused resources—all without compromising security or raising node costs. Historical data shows frequent near-full blocks and Plutus execution bottlenecks, underscoring the urgency as Cardano aims for nation-state-scale usage by 2030.

Leios CIP​

Summary​

  • – the Cardano Improvement Proposal by Duncan Coutts,
  • CIP-0079, proposed by Duncan Coutts in November 2022, introduces Ouroboros Leios as a long-term solution to boost Cardano’s transaction throughput beyond the limitations of Ouroboros Praos. This CIP provides the rationale and a high-level design of the protocol.

Leios Research Paper​

Summary​

  • The original research defining the core protocol and its theoretical properties. Published on May 31, 2024, by Sandro Coretti, Matthias Fitzi, Aggelos Kiayias, Giorgos Panagiotakos, and Alexander Russell, this research paper introduces Leios, a blockchain protocol overlay that transforms low-throughput permissionless protocols (PoW or PoS) into high-throughput systems, achieving near-optimal throughput of (1-δ)σ_H (where σ_H is the honest stake fraction and δ>0) under realistic network conditions. Unlike prior models assuming unbounded message capacity, Leios addresses adversarial tactics like protocol bursts (mass message releases) and equivocations (double-signing in PoS) using a freshest-first diffusion network model (F_FFD). It employs five key techniques: (i) concurrent Input Block (IB) generation for transactions, (ii) Endorser Blocks (EBs) with data availability proofs, (iii) a pipelined architecture for uninterrupted processing, (iv) freshest-first message prioritization with VRF-based timestamps, and (v) equivocation proofs to limit malicious spam. Full Leios ensures throughput scales with network capacity, retains base protocol settlement times (adjusted by a δ-related constant), and supports dynamic participation, proven secure with a stake-based voting scheme using BLS signatures. Applied to Ouroboros, Leios offers a scalable, secure layer-1 solution for Cardano, balancing throughput, latency, and resilience.

Videos​

Presentations​

Tools and simulations​

Development resources​