Ouroboros Peras weekly update - 18 September 2026
This week we continued working on several fronts.
Development update
We reviewed the PerasVotingAnalysis v1.1 report made by ARC researchers and produced a list of questions that should allow us to finalise the delivery plan around crypto for mainnet Peras in the coming weeks.
ObjectDiffusion now has support for graceful termination on the client side and caught-up detection, which is being used as part of the GSM caught-up criterion. This is thanks to ouroboros-network #5431 and ouroboros-consensus #2286. These PRs integrate a full test suite as well. Internal review of the two PRs is in progress.
An initial implementation of ImmutablePerasCertDB is available in ouroboros-consensus #2293. Internal review is in progress as well.
The network design team was able to write a lemma proving that certificates which are relevant for chain selection should arrive in ascending PerasRoundNo order to a node connected to at least one honest peer, provided the usual chain quality and network assumptions hold.
This should simplify the remaining adaptations needed on ObjectDiffusion to serve historical certificates, in addition to existing volatile ones. Work is still in progress here.
The ledger integration team continued its effort to bring the last Peras pieces needed before the code freeze for the incoming hard fork. This includes finalising the list of Peras governable protocol parameters for the constitution update, with an implementation prototype in cardano-ledger #6067.
Consensus
On the consensus side, we also:
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Opened the following PRs fixing some issues blocking nightly and testnet runs:
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Opened a PR for selecting fewer transactions when forging a block that contains a Peras certificate.
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Finalised the initial implementation of certificate size estimation, needed to avoid forging certificates that could potentially not fit inside a block body.
Testnet
The testnet team has focused on quality-of-life improvements, including a better initialisation script and centralised logs and metrics.
In addition, they started updating the testnet base branch to the latest revision of the Peras codebase.
