Struct Anchor

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

A root of either the Sapling or Orchard Zcash note commitment trees.

Anchor is a cryptographic commitment that represents the root of a note commitment tree at a specific block height. It is used in shielded transaction validation to prove that a note being spent was part of the blockchain state without revealing which specific note is being spent.

Zcash Concept Relation

In Zcash’s shielded protocols (Sapling and Orchard), each spent note must reference an anchor to create a zero-knowledge proof showing:

1. The note exists in the blockchain as of a particular state (the anchor)
2. The spender has the authority to spend this note
3. The note has not been previously spent

The anchors are critical for maintaining privacy while preventing double-spending.

Data Preservation

Anchor preserves the exact 256-bit root hash values from wallet data, which are needed when reconstructing or validating shielded transactions during wallet migration.

Examples

// Create an anchor from a u256 value
let anchor = Anchor::new([0u8; 32]);

Implementations

impl Anchor

pub fn new(data: [u8; 32]) -> Self

Creates a new instance from a fixed-size byte array.

This is the primary constructor when you have an exact-sized array available.

pub fn len(&self) -> usize

Returns the length of this blob in bytes.

This will always return $size for this type.

pub fn is_empty(&self) -> bool

Returns true if this blob contains no bytes.

This will always return false for this type (unless $size is 0).

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

Converts this blob to a Vec<u8>, creating a copy of the data.

pub fn as_slice(&self) -> &[u8]

Exposes the underlying byte array as a slice.

pub fn as_bytes(&self) -> &[u8; 32]

Exposes the underlying byte array.

pub fn from_slice(data: &[u8]) -> Result<Self, TryFromSliceError>

Creates an instance from a slice of bytes.

Errors

Returns an error if the slice’s length doesn’t match the expected size ($size).

pub fn from_vec(data: Vec<u8>) -> Result<Self, TryFromSliceError>

Creates an instance from a Vec<u8>.

Errors

Returns an error if the vector’s length doesn’t match the expected size ($size).

pub fn from_hex(hex: &str) -> Result<Self, HexParseError>

Parses an instance from a hex string.

pub fn from_reversed_hex(hex: &str) -> Result<Self, HexParseError>

Parses an instance from a hex string in reversed byte order, such as is used for transaction identifiers and block hashes.

pub fn to_hex(&self) -> String

Formats the bytes of this object as a hex string.

Trait Implementations

impl AsRef<[u8]> for Anchor

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for Anchor

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Anchor

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

Formats the value using the given formatter.

impl From<&[u8]> for Anchor

fn from(data: &[u8]) -> Self

Converts to this type from the input type.

impl From<&Anchor> for CBOR

fn from(data: &Anchor) -> Self

Converts to this type from the input type.

impl From<&Anchor> for Vec<u8>

fn from(blob: &Anchor) -> Vec<u8>

Converts to this type from the input type.

impl From<Anchor> for CBOR

fn from(data: Anchor) -> Self

Converts to this type from the input type.

impl From<Anchor> for Envelope

fn from(value: Anchor) -> Self

Converts to this type from the input type.

impl From<Anchor> for Vec<u8>

fn from(blob: Anchor) -> Vec<u8>

Converts to this type from the input type.

impl From<Vec<u8>> for Anchor

fn from(data: Vec<u8>) -> Self

Converts to this type from the input type.

impl Hash for Anchor

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Anchor

fn eq(&self, other: &Self) -> 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<CBOR> for Anchor

type Error = Error

The type returned in the event of a conversion error.

fn try_from(cbor: CBOR) -> Result<Self, Self::Error>

Performs the conversion.

impl TryFrom<Envelope> for Anchor

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 Copy for Anchor

impl Eq for Anchor