Struct OrchardWitness

pub struct OrchardWitness(/* private fields */);

A cryptographic witness proving that a Orchard note commitment exists in the note commitment tree.

OrchardWitness is a specialized form of incremental Merkle tree witness for the Orchard protocol. It proves that a specific note commitment is included in the global Orchard note commitment tree, which is necessary when spending a note.

Zcash Concept Relation

In Zcash’s Orchard protocol:

• Note Commitment Tree: A Merkle tree containing all Orchard note commitments
• Merkle Path: The path from a leaf (note commitment) to the root of the tree
• Witness: The authentication path proving a leaf exists in the tree
• Anchors: Root hashes of the note commitment tree at specific blockchain heights

When spending a Orchard note, a zero-knowledge proof must demonstrate that the note’s commitment exists in the tree at a specific anchor (root hash), without revealing which specific commitment is being spent. The witness provides the necessary path information to create this proof.

Data Preservation

During wallet migration, complete witness data must be preserved for all unspent notes. This includes:

• The authentication path (sequence of hashes forming the Merkle path)
• The position of the note commitment in the tree
• The tree depth used (32 for Orchard)

Without this witness data, unspent notes cannot be spent as it would be impossible to prove their inclusion in the note commitment tree.

Trait Implementations

impl Clone for OrchardWitness

fn clone(&self) -> OrchardWitness

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for OrchardWitness

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

Formats the value using the given formatter.

impl From<OrchardWitness> for Envelope

fn from(value: OrchardWitness) -> Self

Converts to this type from the input type.

impl PartialEq for OrchardWitness

fn eq(&self, other: &OrchardWitness) -> bool

Tests for self and other values to be equal, and is used by ==.

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

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

impl TryFrom<Envelope> for OrchardWitness

type Error = Error

The type returned in the event of a conversion error.

fn try_from(envelope: Envelope) -> Result<Self, Self::Error>

Performs the conversion.

impl Eq for OrchardWitness

impl StructuralPartialEq for OrchardWitness