Struct KeyImage 

pub struct KeyImage { /* private fields */ }

The protocol’s “linking tag” — what the host stores to prevent double voting.

Mathematically: I_e = x · H_p(domain || election_id || x · G), where x is the secret key, G is the Ristretto255 base point and H_p is the Ristretto hash-to-group construction. Three properties matter:

• it is deterministic for a given secret key and election, so casting the same ballot twice in that election yields the same tag;
• it is election-scoped: reusing the same key in a different election yields a different public tag;
• it is anonymous: nothing about it leaks which member of the ring produced it;
• it is unforgeable: the BLSAG proof is only valid if the tag was actually computed from a secret key that matches one of the public keys in the ring.

Encoded as 32 canonical bytes, identical in shape to a public key.

Implementations

impl KeyImage

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

Encode the tag as 32 canonical bytes.

pub fn from_bytes(bytes: &[u8; 32]) -> Result<Self>

Decode 32 bytes produced by KeyImage::to_bytes.

pub fn to_hex(&self) -> String

Hex-encode using lowercase digits (64 characters).

pub fn from_hex(s: &str) -> Result<Self>

Decode from a 64-character hex string.

pub fn to_prefixed(&self) -> String

Encode in the human-friendly prefixed format: ki_<hex>_<checksum>.

pub fn from_prefixed(s: &str) -> Result<Self>

Decode a ki_<hex>_<checksum> string produced by KeyImage::to_prefixed, verifying the tag and the checksum.

Trait Implementations

impl Clone for KeyImage

fn clone(&self) -> KeyImage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for KeyImage

impl Debug for KeyImage

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

Formats the value using the given formatter.

impl Eq for KeyImage

impl Hash for KeyImage

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 KeyImage

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for KeyImage