Mithril: powering lightweight access to the Cardano blockchain

What is Mithril

Mithril is Cardano’s solution for enabling secure, efficient, and lightweight interactions with the blockchain. By removing the need to download and verify the entire blockchain history, Mithril significantly reduces resource requirements and makes Cardano more accessible for use cases such as:

• Certification of account transactions/balances in browser-based light wallets (including mobile)
• Certification of transactions in layer 2 solutions (bridges, state channels, rollups, etc).

Light clients are applications or devices that do not download the entire blockchain. Instead, they rely on certified snapshots to confirm the network's state. This approach allows light clients to verify blockchain updates quickly and securely without incurring excessive data usage or high storage costs.

Who is Mithril for?

Mithril is ideal for:

• Light wallets. Users can verify transactions and balances quickly, even in browser-based or mobile environments.
• Layer 2 solutions. Bridges, state channels, and rollups can operate efficiently without needing the full blockchain history.
• Stake pool operators (SPOs). SPOs can rapidly bootstrap new nodes using certified snapshots.

For more details, refer to the Mithril guide.

How does Mithril work?

Mithril leverages stake-based multi-signature security, where stakeholders contribute their individual signatures to certify messages. When a quorum of individual signatures is reached, they are aggregated into a multi-signature and embedded in a certificate. The authenticity of this information can then be verified without running a full node.

The Mithril signer computes the messages, creates the individual signatures, and broadcasts them. The Mithril aggregator collects and aggregates the individual signatures. The Mithril client interacts with a Mithril aggregator to retrieve and compute messages from artifacts and verify their authenticity against fetched certificates.

This verification process eliminates the need for clients to reprocess or download the entire blockchain, saving significant computational resources and time.

Key advantages

The teams are also considering leveraging the succinctness of zero-knowledge proofs (ZKPs). This property can unlock use cases where the size of the Mithril certificates is a factor, particularly for on-chain storage and/or verification of the Mithril certificates (on Cardano or any other blockchain).

Advanced techniques, such as recursive or folding-based succinct non-interactive argument of knowledge (SNARKs), are also being explored to further compress the Mithril certificate chain. Ongoing research is currently focused on leveraging the ALBA proof system as a SNARK-friendly aggregation proof system for the Mithril multi-signatures.

Conclusion

Mithril powers a wide range of light access use cases by allowing users to securely verify certified states from the Cardano blockchain without needing to run a full node. This significantly lowers resource requirements and promotes broader blockchain adoption across light wallets, mobile applications, and layer 2 solutions.

Currently in beta, Mithril is progressing along two main development paths:

• Further decentralizing the network by distributing aggregation processes.
• Creating more succinct certificates using advanced cryptographic techniques, including ZKPs.

These ongoing enhancements aim to strengthen Mithril’s scalability, privacy, and usability, expanding its role in delivering efficient, lightweight blockchain access.

For more details on Mithril’s development, technical documentation, or usage guidelines, see the Mithril documentation website.