Enum exonum_merkledb::HashTag

#[repr(u8)]
pub enum HashTag {
    Blob,
    ListBranchNode,
    ListNode,
    MapNode,
    MapBranchNode,
}

MerkleDB hash prefixes.

Variants

Blob

Hash prefix of a blob.

ListBranchNode

Hash prefix of a branch node of the merkle tree.

ListNode

Hash prefix of the list object.

MapNode

Hash prefix of the map object.

MapBranchNode

Hash prefix of the map branch node object.

Methods

impl HashTag

Calculate hash value with the specified prefix.

In MerkleDB, all data is presented as objects. Objects are divided into blobs and collections (lists / maps), which in their turn are divided into hashable and non-hashable. ProofListIndex and ProofMapIndex relate to hashable collections. For these collections, one can define a hash, which is used to build proof for their contents. In the future, these hashes will be used to build proofs for object hierarchies.

Different hashes for leaf and branch nodes of the list are used to secure merkle tree from the pre-image attack.

See more information here.

pub fn hash_leaf(value: &[u8]) -> Hash

Convenience method to obtain a hashed value of the merkle tree leaf.

pub fn hash_node(left_hash: &Hash, right_hash: &Hash) -> Hash

Convenience method to obtain hashed value of the merkle tree node.

pub fn hash_single_node(hash: &Hash) -> Hash

Convenience method to obtain a hashed value of the merkle tree node with one child.

pub fn hash_list_node(len: u64, root: Hash) -> Hash

Hash of the list object.

h = sha-256( HashTag::ListNode || len as u64 || merkle_root )

pub fn empty_list_hash() -> Hash

Hash of the empty list object.

Empty list hash:

h = sha-256( HashTag::ListNode || 0 || Hash::default() )

pub fn hash_list(hashes: &[Hash]) -> Hash

Computes a list hash for the given list of hashes.

pub fn hash_map_node(root: Hash) -> Hash

Hash of the map object.

h = sha-256( HashTag::MapNode || merkle_root )

pub fn hash_map_branch(branch_node: &[u8]) -> Hash

Hash of the map branch node.

h = sha-256( HashTag::MapBranchNode || <left_key> || <right_key> || <left_hash> || <right_hash> )

pub fn hash_single_entry_map(path: &ProofPath, h: &Hash) -> Hash

Hash of the map with single entry.

h = sha-256( HashTag::MapBranchNode || <key> || <child_hash> )

pub fn empty_map_hash() -> Hash

Hash of the empty map object.

Empty map hash:

sha-256( HashTag::MapNode || Hash::default() )

Trait Implementations

impl Clone for HashTag

fn clone(&self) -> HashTag

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for HashTag

impl Debug for HashTag

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.