# 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 (unless in catch-up mode or seed unknown).
* 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`.

## Transaction validation

* Signature and encoding checks.
* 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/primitives/src/block_header.rs`
* `crates/dbs/storage/src/impls/merkle_patricia_trie/trie_proof.rs`