Notice

Miden's Nullifier Set Design: An Invisible Innovation to Address Blockchain State Bloat

@0xMiden's privacy model relies on nullifier sets to prevent double spending and track asset states, but traditional solutions face a fatal issue: nullifier sets grow infinitely with transactions, leading to excessive storage burdens on nodes. For example, if the on-chain TPS is 1000, after 10 years, nullifier data could expand to 10TB, making it impossible for ordinary devices to participate in network synchronization.

The breakthrough of Miden lies in the introduction of the Nullifier Tree structure divided by epochs:

Split the nullifier set by time windows (such as 6 months per epoch), and nodes only need to keep the complete data of the most recent 2 epochs, while historical data only retains the root hash.
When users consume early assets, they must provide proof to verify that the asset has not been consumed during the corresponding epoch at the time of creation and thereafter.

The deeper meaning of this design:

1. Balancing state growth and decentralization: Node storage pressure shifts from "unlimited growth" to a fixed threshold, significantly lowering the long-term participation barrier.
2. Synergy of Privacy and Scalability: The combination of nullifier's epoch partitioning and local proof generation protects the privacy of transaction linkage while avoiding global state inflation.
3. Redistribution of responsibilities between users and the network: Users need to keep proof of old assets themselves, and the blockchain only needs to verify rather than store. This "decentralization of responsibility" is a key exploration for the sustainability of blockchain, similar to the collaborative logic between CDN and clients in the internet.

Miden has found a balance between "full node centralization" and "privacy computing costs" through the engineering innovation of nullifiers. This is not only a technical optimization but also suggests the future evolution direction of blockchains: the chain does not have to carry all history, but rather intelligently allocates verification responsibilities through cryptographic tools.
Shenzhen Chen Village Committee Party Branch