Module 0x1::sigma_protocol_statement

• Struct Statement
• Constants
• Function new_statement
• Function get_point
• Function get_scalars
• Function get_points
• Function get_compressed_points

use 0x1::error;
use 0x1::ristretto255;

Struct Statement

A public statement consists of:

• a points vector of $n_1$ group elements
• a compressed_points vector of $n_1$ compressed group elements (redundant, for faster Fiat-Shamir)
• a scalars vector of $n_2$ scalars

The phantom type parameter P tags the statement with a specific protocol marker type (e.g., Registration, KeyRotation, etc.) for compile-time safety.

struct Statement<P> has drop

Constants

When creating a Statement, the # of points must match the # of compressed points.

const E_MISMATCHED_NUMBER_OF_COMPRESSED_POINTS: u64 = 1;

Function new_statement

public(friend) fun new_statement<P>(points: vector<ristretto255::RistrettoPoint>, compressed_points: vector<ristretto255::CompressedRistretto>, scalars: vector<ristretto255::Scalar>): sigma_protocol_statement::Statement<P>

public(friend) fun new_statement<P>(
    points: vector<RistrettoPoint>,
    compressed_points: vector<CompressedRistretto>,
    scalars: vector<Scalar>
): Statement<P> {
    assert!(points.length() == compressed_points.length(), error::invalid_argument(E_MISMATCHED_NUMBER_OF_COMPRESSED_POINTS));
    Statement { points, compressed_points, scalars }
}

Function get_point

Returns the $i$th elliptic curve point in the public statement.

public(friend) fun get_point<P>(self: &sigma_protocol_statement::Statement<P>, i: u64): &ristretto255::RistrettoPoint

public(friend) fun get_point<P>(self: &Statement<P>, i: u64): &RistrettoPoint {
    &self.points[i]
}

Function get_scalars

Returns all the scalars in the statement. (Needed to feed in the statement in the Fiat-Shamir transform.)

public(friend) fun get_scalars<P>(self: &sigma_protocol_statement::Statement<P>): &vector<ristretto255::Scalar>

public(friend) fun get_scalars<P>(self: &Statement<P>): &vector<Scalar> {
    &self.scalars
}

Function get_points

Returns all the elliptic curve points in the statement.

public(friend) fun get_points<P>(self: &sigma_protocol_statement::Statement<P>): &vector<ristretto255::RistrettoPoint>

public(friend) fun get_points<P>(self: &Statement<P>): &vector<RistrettoPoint> {
    &self.points
}

Function get_compressed_points

Returns all the compressed elliptic curve points in the statement. (Needed to feed in the statement in the Fiat-Shamir transform.)

public(friend) fun get_compressed_points<P>(self: &sigma_protocol_statement::Statement<P>): &vector<ristretto255::CompressedRistretto>

public(friend) fun get_compressed_points<P>(self: &Statement<P>): &vector<CompressedRistretto> {
    &self.compressed_points
}