> For the complete documentation index, see [llms.txt](https://docs.mazze.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mazze.io/architecture/verification.md).

# Verification

Verification rules ensure that incoming blocks and transactions are valid before they enter consensus.

## Header validation

`verify_header_params` checks:

* Custom data length and custom prefix for fork markers.
* Presence of `base_price`.
* Proof of Work validity, skipped only in catch-up mode. A block whose RandomX seed hash cannot be resolved is rejected; it is no longer accepted without a PoW check.
* Referee count bound and duplicate parent/referee hashes.
* Basic timestamp validity (when enabled).

## Block integrity

* Transactions root is re-computed via MPT and compared to the header.
* Block size is checked against `max_block_size_in_bytes`.

## Shielded section (stage A)

`verify_sync_graph_block_basic` checks a block's shielded section before the block enters the sync graph:

1. The block is at a slot height, and the section is within the per-block count.
2. Every body pays exactly the constant fee.
3. Nullifiers are distinct across the section.
4. Every proof verifies against its body (`verify_body`): pool version, proof system, proof length cap, `proof_hash`, canonical decoding, then the STARK.

A proof that does not match its body's `proof_hash` is the peer's fault and the block is requested again. Any other failure makes the block invalid. Blocks re-read from the node's own database skip the proofs. A block that charges shielded gas is invalid.

## Sync-graph bounds

Outside catch-up mode, the sync graph holds at most 200,000 blocks (`SYNC_GRAPH_ARENA_HARD_CAP`). Blocks beyond the cap are rejected and counted.

## Transaction validation

* Signature and encoding checks.
* Intrinsic gas: a native transaction whose gas limit is below its intrinsic gas is dropped before execution (`NotEnoughGasLimit`).
* Gas, storage, and epoch height bounds.
* Chain id and space-specific rules.

## Base fee and gas checks

`verify_sync_graph_ready_block` verifies that:

* Packed gas does not exceed per-space limits.
* Base price is correctly derived from parent and gas usage.

## Inclusion proofs

The verification module exposes helpers to compute and verify:

* Transaction inclusion proofs.
* Block receipt proofs.
* Epoch receipt proofs.

These are used by RPCs and light client workflows.

## Key source files

* `crates/mazzecore/core/src/verification.rs`
* `crates/shielded_pq/src/verify.rs`
* `crates/primitives/src/block_header.rs`
* `crates/dbs/storage/src/impls/merkle_patricia_trie/trie_proof.rs`