CIP for Mithril signature diffusion through Cardano network

[jpraynaud]

Why

We want to decentralize Mithril networks and have the capability of running multiple aggregators:

• Avoid the need to build and configure an alternate networking/relaying mechanism
• Strengthen security of Mithril system by isolating the signer from the outside world
• Enable development of independent alternate aggregators

Note

At this stage of the Mithril-Cardano integration process, we won't consider integration of Mithril signer capabilities in the core Cardano node.

Bootstrap generic diffusion protocol

While in the short term this system would serve Mithril's needs, it seems a relatively generic mechanism to diffuse messages across the network would benefit other planned features.
In particular, Ouroboros Peras and Leios will necessitate such a feature to propagate votes.

Mithril signature figures

The mithril signer process requires some resources:

• RAM < 50MB w/ spike at 1GB when signing
• CPU ~1% (Current mean use, 50-70% upon signing
• Disk space ~2GB

Network Resources for signatures diffusion:

• Size of signatures: ~500B - 2KB
• Number of signatures broadcast / round: ~3,000
• Frequency of signatures: every 1 min
  => Overall throughput ~50-100KB/s

Other Questions/Remarks

• The signature diffusion does not need 100% guarantee of delivery
• What would be the impact of Mithril integration on the attack surface area of the Cardano node?
• How to avoid tight coupling between Mithril and Cardano?
• How to align Mithril integration with Cardano being designed towards a multi-implementation system?

What

Design Mithril signature diffusion with the Cardano network:

• First step of Mithril integration with Cardano
• Leverage Cardano network for individual single signatures diffusion

How

• Design and redact a draft CIP
• Create a PR on the CIPs repository
• Handle first round of reviews
• Allocate a CIP category: Network
• Allocate a CIP number: CIP-0137
• Handle second round of reviews by CIP editiors
• Merge the CIP PR

[jpraynaud]

The draft CIP PR has been created on the CIPs repository: cardano-foundation/CIPs#876

[jpraynaud]

The CIP 137 has been merged 🎉 and is available at:

• https://github.com/cardano-foundation/CIPs/tree/master/CIP-0137
• https://cips.cardano.org/cip/CIP-0137