# Trait ethcore::client::ProvingBlockChainClient [−] [src]

    pub trait ProvingBlockChainClient: BlockChainClient {
        fn prove_storage(&self,
                     key1: H256,
                     key2: H256,
                     from_level: u32,
                     id: BlockId)
                     -> Vec<Bytes>;
        fn prove_account(&self, key1: H256, from_level: u32, id: BlockId) -> Vec<Bytes>;
        fn code_by_hash(&self, account_key: H256, id: BlockId) -> Bytes;
    }

Extended client interface for providing proofs of the state.

## Required Methods

### `fn prove_storage(&self,
key1: H256,
key2: H256,
from_level: u32,
id: BlockId)
-> Vec<Bytes>`

Prove account storage at a specific block id.

Both provided keys assume a secure trie. Returns a vector of raw trie nodes (in order from the root) proving the storage query. Nodes after `from_level` may be omitted. An empty vector indicates unservable query.

### `fn prove_account(&self, key1: H256, from_level: u32, id: BlockId) -> Vec<Bytes>`

Prove account existence at a specific block id. The key is the keccak hash of the account's address. Returns a vector of raw trie nodes (in order from the root) proving the query. Nodes after `from_level` may be omitted. An empty vector indicates unservable query.

### `fn code_by_hash(&self, account_key: H256, id: BlockId) -> Bytes`

Get code by address hash.

## Implementors

- `impl ProvingBlockChainClient for TestBlockChainClient`
- `impl ProvingBlockChainClient for Client`

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