Struct winter_crypto::BatchMerkleProof

pub struct BatchMerkleProof<H: Hasher> {
    pub leaves: Vec<H::Digest>,
    pub nodes: Vec<Vec<H::Digest>>,
    pub depth: u8,
}

Multiple Merkle paths aggregated into a single proof.

The aggregation is done in a way which removes all duplicate internal nodes, and thus, it is possible to achieve non-negligible compression as compared to naively concatenating individual Merkle paths. The algorithm is for aggregation is a variation of Octopus.

Currently, at most 255 paths can be aggregated into a single proof. This limitation is imposed primarily for serialization purposes.

Fields

leaves: Vec<H::Digest>

The leaves being proven

nodes: Vec<Vec<H::Digest>>

Hashes of Merkle Tree proof values above the leaf layer

depth: u8

Depth of the leaves

Implementations

impl<H: Hasher> BatchMerkleProof<H>

pub fn from_paths(
    paths: &[Vec<H::Digest>],
    indexes: &[usize]
) -> BatchMerkleProof<H>

Constructs a batch Merkle proof from individual Merkle authentication paths.

Panics

Panics if:

• No paths have been provided (i.e., paths is an empty slice).
• More than 255 paths have been provided.
• Number of paths is not equal to the number of indexes.
• Not all paths have the same length.

pub fn get_root(&self, indexes: &[usize]) -> Result<H::Digest, MerkleTreeError>

Computes a node to which all Merkle paths aggregated in this proof resolve.

Errors

Returns an error if:

• No indexes were provided (i.e., indexes is an empty slice).
• Number of provided indexes is greater than 255.
• Any of the specified indexes is greater than or equal to the number of leaves in the tree for which this batch proof was generated.
• List of indexes contains duplicates.
• The proof does not resolve to a single root.

pub fn into_paths(
    self,
    indexes: &[usize]
) -> Result<Vec<Vec<H::Digest>>, MerkleTreeError>

Computes the uncompressed Merkle paths which aggregate to this proof.

Errors

Returns an error if:

• No indexes were provided (i.e., indexes is an empty slice).
• Number of provided indexes is greater than 255.
• Number of provided indexes does not match the number of leaf nodes in the proof.

pub fn serialize_nodes(&self) -> Vec<u8>

Converts all internal proof nodes into a vector of bytes.

Panics

Panics if:

• The proof contains more than 255 Merkle paths.
• The Merkle paths consist of more than 255 nodes.

pub fn deserialize<R: ByteReader>(
    node_bytes: &mut R,
    leaves: Vec<H::Digest>,
    depth: u8
) -> Result<Self, DeserializationError>

Parses internal nodes from the provided node_bytes, and constructs a batch Merkle proof from these nodes, provided leaves, and provided tree depth.

Errors

Returns an error if:

• No leaves were provided (i.e., leaves is an empty slice).
• Number of provided leaves is greater than 255.
• Tree depth was set to zero.
• node_bytes could not be deserialized into a valid set of internal nodes.

Trait Implementations

impl<H: Clone + Hasher> Clone for BatchMerkleProof<H>where
    H::Digest: Clone,
    H::Digest: Clone,

fn clone(&self) -> BatchMerkleProof<H>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<H: Debug + Hasher> Debug for BatchMerkleProof<H>where
    H::Digest: Debug,
    H::Digest: Debug,

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

Formats the value using the given formatter.

impl<H: PartialEq + Hasher> PartialEq<BatchMerkleProof<H>> for BatchMerkleProof<H>where
    H::Digest: PartialEq,
    H::Digest: PartialEq,

fn eq(&self, other: &BatchMerkleProof<H>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<H: Eq + Hasher> Eq for BatchMerkleProof<H>where
    H::Digest: Eq,
    H::Digest: Eq,

impl<H: Hasher> StructuralEq for BatchMerkleProof<H>

impl<H: Hasher> StructuralPartialEq for BatchMerkleProof<H>