Struct Ring 

pub struct Ring<F: PrimeField, KzgCurve: Pairing<ScalarField = F>, VrfCurveConfig: TECurveConfig<BaseField = F>> {
    pub cx: KzgCurve::G1Affine,
    pub cy: KzgCurve::G1Affine,
    pub selector: KzgCurve::G1Affine,
    pub max_keys: usize,
    pub curr_keys: usize,
    pub padding: Affine<VrfCurveConfig>,
}

Commitment to a list of VRF public keys as is used as a public input to the ring proof SNARK verifier.

The VRF keys are (inner) curve points that we represent in the affine Twisted Edwards coordinates. We commit to the coordinate vectors independently using KZG on the outer curve. To make the commitment updatable we use SRS in the Lagrangian form: L1, ..., Ln, where Li = L_i(t)G. The commitment to a vector a1, ..., an is then a1L1 + ... + anLn.

We pad the list of keys with a padding point with unknown dlog up to a certain size. Additionally, to make the commitment compatible with the snark, we append the power-of-2 powers of the VRF blinding Pedersen base H, 2H, 4H, ..., 2^(s-1)H, where s is the bitness of the VRF curve scalar field. The last IDLE_ROWS = 4 elements are set to (0, 0).

Thus, the vector of points we commit to coordinatewise is pk1, ..., pkn, padding, ..., padding, H, 2H, ..., 2^(s-1)H, 0, 0, 0, 0

Fields

cx: KzgCurve::G1Affine

KZG commitment to the x coordinates of the described vector.

cy: KzgCurve::G1Affine

KZG commitment to the y coordinates of the described vector.

selector: KzgCurve::G1Affine

KZG commitment to a bitvector highlighting the part of the vector corresponding to the public keys.

max_keys: usize

Maximal number of keys the commitment can “store”. For domain of size N it is N - (s + IDLE_ROWS).

curr_keys: usize

Number of keys “stored” in this commitment.

padding: Affine<VrfCurveConfig>

Implementations

impl<F: PrimeField, KzgCurve: Pairing<ScalarField = F>, VrfCurveConfig: TECurveConfig<BaseField = F>> Ring<F, KzgCurve, VrfCurveConfig>

pub fn empty( piop_params: &PiopParams<F, VrfCurveConfig>, srs: impl Fn(Range<usize>) -> Result<Vec<KzgCurve::G1Affine>, ()>, g: KzgCurve::G1, ) -> Self

Builds the commitment to the vector padding, ..., padding, H, 2H, ..., 2^(s-1)H, 0, 0, 0, 0.

We compute it as a sum of commitments of 2 vectors: padding, ..., padding, and 0, ..., 0, (H - padding), (2H - padding), ..., (2^(s-1)H - padding), -padding, -padding, -padding, -padding. The first one is padding * G, the second requires an (IDLE_ROWS + s)-msm to compute.

• piop_params: SNARK parameters
• srs: Should return srs[range] for range = (piop_params.keyset_part_size..domain_size)
• g: Generator used in the SRS

pub fn append( &mut self, keys: &[Affine<VrfCurveConfig>], srs: impl Fn(Range<usize>) -> Result<Vec<KzgCurve::G1Affine>, ()>, )

Appends a set key sequence to the ring.

• keys: Keys to append.
• srs: Should return srs[range] for range = (self.curr_keys..self.curr_keys + keys.len())

pub fn with_keys( piop_params: &PiopParams<F, VrfCurveConfig>, keys: &[Affine<VrfCurveConfig>], srs: &RingBuilderKey<F, KzgCurve>, ) -> Self

Builds the ring from the keys provided with 2 MSMs of size keys.len() + scalar_bitlen + 5.

In some cases it may be beneficial to cash the empty ring, as updating it costs 2 MSMs of size keys.len().

• piop_params: SNARK parameters.
• srs: full-size Lagrangian SRS.

pub fn slots_left(&self) -> usize

pub const fn empty_unchecked( domain_size: usize, cx: KzgCurve::G1Affine, cy: KzgCurve::G1Affine, selector: KzgCurve::G1Affine, padding: Affine<VrfCurveConfig>, ) -> Self

Trait Implementations

impl<F: PrimeField, KzgCurve: Pairing<ScalarField = F>, VrfCurveConfig: TECurveConfig<BaseField = F>> CanonicalDeserialize for Ring<F, KzgCurve, VrfCurveConfig>

fn deserialize_with_mode<R: Read>( reader: R, compress: Compress, validate: Validate, ) -> Result<Self, SerializationError>

The general deserialize method that takes in customization flags.

fn deserialize_compressed<R>(reader: R) -> Result<Self, SerializationError>

where R: Read,

fn deserialize_compressed_unchecked<R>( reader: R, ) -> Result<Self, SerializationError>

where R: Read,

fn deserialize_uncompressed<R>(reader: R) -> Result<Self, SerializationError>

where R: Read,

fn deserialize_uncompressed_unchecked<R>( reader: R, ) -> Result<Self, SerializationError>

where R: Read,

impl<F: PrimeField, KzgCurve: Pairing<ScalarField = F>, VrfCurveConfig: TECurveConfig<BaseField = F>> CanonicalSerialize for Ring<F, KzgCurve, VrfCurveConfig>

fn serialize_with_mode<W: Write>( &self, writer: W, compress: Compress, ) -> Result<(), SerializationError>

The general serialize method that takes in customization flags.

fn serialized_size(&self, compress: Compress) -> usize

fn serialize_compressed<W>(&self, writer: W) -> Result<(), SerializationError>

where W: Write,

fn compressed_size(&self) -> usize

fn serialize_uncompressed<W>(&self, writer: W) -> Result<(), SerializationError>

where W: Write,

fn uncompressed_size(&self) -> usize

impl<F: Clone + PrimeField, KzgCurve: Clone + Pairing<ScalarField = F>, VrfCurveConfig: Clone + TECurveConfig<BaseField = F>> Clone for Ring<F, KzgCurve, VrfCurveConfig>

where KzgCurve::G1Affine: Clone,

fn clone(&self) -> Ring<F, KzgCurve, VrfCurveConfig>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: PrimeField, KzgCurve: Pairing<ScalarField = F>, VrfCurveConfig: TECurveConfig<BaseField = F>> Debug for Ring<F, KzgCurve, VrfCurveConfig>

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

Formats the value using the given formatter.

impl<F: PartialEq + PrimeField, KzgCurve: PartialEq + Pairing<ScalarField = F>, VrfCurveConfig: PartialEq + TECurveConfig<BaseField = F>> PartialEq for Ring<F, KzgCurve, VrfCurveConfig>

where KzgCurve::G1Affine: PartialEq,

fn eq(&self, other: &Ring<F, KzgCurve, VrfCurveConfig>) -> 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<F: PrimeField, KzgCurve: Pairing<ScalarField = F>, VrfCurveConfig: TECurveConfig<BaseField = F>> Valid for Ring<F, KzgCurve, VrfCurveConfig>

fn check(&self) -> Result<(), SerializationError>

fn batch_check<'a>( batch: impl Iterator<Item = &'a Self> + Send, ) -> Result<(), SerializationError>

where Self: 'a,

impl<F: Eq + PrimeField, KzgCurve: Eq + Pairing<ScalarField = F>, VrfCurveConfig: Eq + TECurveConfig<BaseField = F>> Eq for Ring<F, KzgCurve, VrfCurveConfig>

where KzgCurve::G1Affine: Eq,

impl<F: PrimeField, KzgCurve: Pairing<ScalarField = F>, VrfCurveConfig: TECurveConfig<BaseField = F>> StructuralPartialEq for Ring<F, KzgCurve, VrfCurveConfig>