Ouroboros Peras

Implementation Progress Update and Discussion

August 31, 2026

Agenda

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1. Integration progress
2. Team augmentation
3. Peras → Mainnet kickoff
• Ledger and crypto integration
• Peras ↔ Genesis / Historical certificates
• Networking improvements
4. Peras Testnet
5. Next steps and communication strategy
6. Discussion

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Disclaimer

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• Ouroboros Peras is a protocol that enables significantly faster settlement times under optimistic conditions

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• At a fixed schedule, all eligible pools vote for a recent block
• If sufficiently many pools vote for the same block, this block receives a boost, making it unlikely to be rolled back
• Otherwise, the system enters a cooldown period, during which no voting takes place

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• Unless explicitly stated, in these slides we refer exclusively to pre-alpha Peras:

https://tweag.github.io/cardano-website/projects/prs/documentation/overview/#pre-alpha-peras

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• More resources: �https://github.com/tweag/cardano-peras#resources-on-peras�
• Past demos (recordings, slides, etc.): �https://tweag.github.io/cardano-website/

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Integration progress

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• About +13.7kLoC/-4.2kLoC �
• Most of the integration work has already landed on main
• Merged: 33 PRs (Peras 28 → 60)
• Current stack: 7 PRs (1 approved, 5 ready for review, 1 draft) (Peras 61 → 67)�
• Some pieces will remain in our integration branch until we are done glueing some corners back:
• Integrating properly-registered public BLS keys (WIP)
• Handling the node’s own private BLS key and identity (WIP)
• Handling the way certificates are included in Dijkstra block bodies (TBD)

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In the last two months we stacked a lot of changes on our dedicated development branch for ouroboros-consensus because we needed to do a wide and deep refactor of multiple components.

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Now we are mostly done integrating these changes into main!

Integration progress

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Team augmentation

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We welcomed 6 talented Tweagers to help us with Peras-to-mainnet phase:

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• Evgenii Akentev (testnet team)
• Gaël Deest (ledger team)
• Xavier Gongora (historical cert/Genesis team)
• Nathan Bloomfield (historical cert/Genesis team)
• Erin van der Veen (network team)
• Philipp Zander (network team)

Peras → Mainnet kickoff

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continuous integration and testing

testnet-ready Peras

mainnet-ready Peras

Aug 2026

Sep 2026

Q1 2027

Jul 2025

(not to scale)

Including all changes needed to enable Peras in the next intra-era hard-fork

Peras → Mainnet kickoff�Ledger and crypto integration

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• Integrating properly-registered public BLS keys into the Peras voting committee
• Now possible thanks to some of the shared efforts led by Leios

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• Sourcing a node’s private BLS key and identity from configuration files
• Exposition of this data should be minimal, similar to block forging credentials�
• Handling the way certificates are included in Dijkstra block bodies
• We currently use opaque byte arrays, leaving all responsibility to the Consensus layer
• We are investigating how to split this responsibility between the Ledger and Consensus

Peras → Mainnet kickoff�Peras ↔ Genesis / Historical certificates

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• Genesis is a protocol which enables syncing nodes to not rely on a particular trusted node�
• Testnet-ready Peras only considers caught-up nodes
• As a consequence, certificates are volatile: they are discarded when they can no longer impact chain selection�
• We must make sure that catching-up nodes converge towards the same chain as honest caught-up nodes, so they should account for certificates when syncing
• Certificates can no longer be volatile. They should be stored and diffused, and Genesis must be adapted to account for them

Peras → Mainnet kickoff�Networking improvements

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Peras → Mainnet kickoff�Networking improvements�timely termination from the client

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Peras → Mainnet kickoff�Networking improvements

Peras → Mainnet kickoff�Networking improvements�timely termination from the client

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Peras → Mainnet kickoff�Networking improvements

Peras → Mainnet kickoff�Networking improvements�caught-up status

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Peras Testnet

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• Testnet now either starts on/transitions to Dijkstra
• Plumbing the private keys & pool id environment variables (temporary)
• Bootstrapping the voting process
• Tracing and checking the behavior of the vote forging thread
• Ensuring and verifying vote generation
• Looking into setting up the flexible scenarios with groups of nodes

Next steps and communication strategy

• We will wrap up peras-to-testnet project in the coming weeks as soon as all the required code is merged and testnet experiments are successful

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• Peras-to-mainnet teams are already at full speed to ensure project delivery as soon as possible

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Communication strategy:

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• Moving forward, our demos will be scheduled every time we achieve a new important step in the project, instead of having a predefinite cadence. This should let us show more interesting content to a broader audience, especially with testnet scenarios.

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• Technical weekly updates will continue to be published diligently to provide clarity and accountability on the project progression

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• We also created https://peras-tracker.tweag.io/ for a higher-level view on the project activity and completion status

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THANK YOU!