Struct SessionId 

pub struct SessionId { /* private fields */ }

An identifier for a session (can be re-used).

A session allows RPs to ensure that it’s still the same World ID interacting with them across multiple interactions.

A SessionId is obtained after creating an initial session.

See the diagram below on how Session Proofs work, the SessionId and the r seed

Note that the action stored here is unrelated to the randomized action used internally by SessionNullifiers — that randomized action exists only to ensure the circuit’s nullifier output is unique per Session Proof.

Implementations

impl SessionId

pub fn new(commitment: FieldElement, oprf_seed: FieldElement) -> Self

Creates a new session id. Most uses should default to from_r_seed instead.

Panics

If the provided oprf_seed is not prefixed with a 0x01 byte.

pub fn from_r_seed<R: CryptoRng + RngCore>( leaf_index: u64, session_id_r_seed: FieldElement, oprf_seed: Option<FieldElement>, rng: &mut R, ) -> Result<Self, &str>

Initializes a SessionId from the OPRF-output seed (r), and the oprf_seed used as input for the OPRF computation.

This matches the logic in oprf_nullifier.circom for computing the commitment from the OPRF seed.

Seed (session_id_r_seed)

• The seed is and MUST be computationally indistinguishable from random, i.e. uniformly distributed because it uses OPRF.
• When computed, the OPRF nodes will use the same oprfKeyId for the RP, with a different domain separator.
• Requesting this seed requires a properly signed request from the RP and a complete query proof.
• The seed generation is based on a randomly generated seed used as an “action” in a Query Proof. Note this action is different than the randomized action used internally by SessionNullifiers.

pub const fn commitment(&self) -> FieldElement

Returns the commitment value.

pub const fn oprf_seed(&self) -> FieldElement

Returns the oprf_seed value.

pub fn to_compressed_bytes(&self) -> [u8; 64]

Returns the 64-byte big-endian representation (2 x 32-byte field elements).

pub fn from_compressed_bytes(bytes: &[u8]) -> Result<Self, String>

Constructs from compressed bytes (must be exactly 64 bytes).

Errors

Returns an error if the input is not exactly 64 bytes or if values are not valid field elements.

Trait Implementations

impl Clone for SessionId

fn clone(&self) -> SessionId

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SessionId

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

Formats the value using the given formatter.

impl Default for SessionId

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for SessionId

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Hash for SessionId

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 SessionId

fn eq(&self, other: &SessionId) -> 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 Serialize for SessionId

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for SessionId

impl Eq for SessionId

impl StructuralPartialEq for SessionId