Obsidian separates execution from data transport. EVM transactions are computationally intensive but relatively small. The Silica Protocol uses spare network capacity to carry larger, non-executable data payloads that need minimal CPU processing.
Message payloads are propagated as data sidecars. These are gossiped peer-to-peer, erasure-coded, and verified by lane committees. They are part of the blockchain protocol but intentionally kept outside the block body.
Validators hold erasure-coded chunks during the retention window (~18 days). After that, archive nodes preserve the full history. Anyone can run an archive node and earn from the archive pool (50% of PM fees) for serving historical data.
The network is divided into parallel lanes. Each lane has a rotating committee of validators assigned to it. Messages are deterministically routed based on sender address.
lane = Hash("LANE_V2", chain_id, sender) mod lane_countAll messages from a single sender go to the same lane. Nodes can immediately determine which lane committee should receive a message without knowing the current slot or RANDAO state.
Two message classes share the same data plane with different economics.
Include a fee bid and are sorted by bid amount (highest first) within each lane batch. Signed debit authorization means the fee is deducted at inclusion time.
Sorted by bid (highest first).
No bid required. A VDF (Verifiable Delay Function) proof provides spam resistance instead. VDFs are sequential computations that cannot be parallelized, creating a natural rate limit.
FIFO within lane.
Most DA solutions use Data Availability Sampling, where light clients randomly sample chunks. Obsidian takes a different approach: committee attestation is the acceptance criteria.
| Aspect | DAS-primary (Ethereum) | Committee-primary (Obsidian) |
|---|---|---|
| Block acceptance | Requires successful sampling. | Requires committee QC (2/3 threshold). |
| Primary verification | Light clients sample randomly. | Committee members prove chunk possession. |
| Parallelism | Single blob space per block. | Multiple lanes with dedicated committees. |
| Acceptance | Probabilistic. | Deterministic. |
A valid certificate proves that a supermajority of the lane committee had the data when they signed. With erasure coding, this means the data can always be reconstructed.
Data does not live in blocks. It lives in the Silica data plane. Blocks only contain compact cryptographic commitments that reference the actual payloads stored elsewhere.
This separation allows for sharded storage: archive nodes can specialize by storing only specific epoch ranges or lane subsets. A node might store epochs 1-1000, another epochs 1001-2000. Together they preserve the full history without any single node needing all 263 TB per year.
Each message batch is split into data chunks and expanded with parity chunks using Reed-Solomon encoding. The original data can be reconstructed from any 50% of chunks.
At 263 TB per year, traditional store-everything archives become impractical. Obsidian solves this with epoch-range sharding.
Priority message fees are distributed among protocol participants. Rather than prepaying fees, priority messages include a signed debit authorization. The proposer deducts the bid from the sender's balance at inclusion time.
Full technical specification of the Silica Protocol, consensus modifications, and economic model.