circuits/TransactionValidator.cpp

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Functions

	Name
pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type	GeneratePointFromSeedAndTotp(pallas::scalar_field_type::value_type seed, pallas::scalar_field_type::value_type provided_totp, typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type generator) Generates a point from the seed, TOTP and generator.
bool	ValidateTransactionValues(uint64_t balance, uint64_t amount, pallas::scalar_field_type::value_type balance_scalar, pallas::scalar_field_type::value_type amount_scalar, typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type balance_commitment, typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type amount_commitment, typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type expected_new_balance_commitment, typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type generator, std::array< pallas::scalar_field_type::value_type, MAX_RANGES > ranges) Validates the transaction values.

Detailed Description

Date: 2025-01-29 Henrique A. Klein ([email protected])

Functions Documentation

function GeneratePointFromSeedAndTotp

pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type GeneratePointFromSeedAndTotp(
    pallas::scalar_field_type::value_type seed,
    pallas::scalar_field_type::value_type provided_totp,
    typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type generator
)

Generates a point from the seed, TOTP and generator.

Parameters:

• seed The seed to be used
• provided_totp The TOTP to be used
• generator The generator point to be used

Return: A point that represents the mapping of TOTP and seed combined

function ValidateTransactionValues

bool ValidateTransactionValues(
    uint64_t balance,
    uint64_t amount,
    pallas::scalar_field_type::value_type balance_scalar,
    pallas::scalar_field_type::value_type amount_scalar,
    typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type balance_commitment,
    typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type amount_commitment,
    typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type expected_new_balance_commitment,
    typename pallas::template g1_type< nil::crypto3::algebra::curves::coordinates::affine >::value_type generator,
    std::array< pallas::scalar_field_type::value_type, MAX_RANGES > ranges
)

Validates the transaction values.

Parameters:

• balance The raw balance in integer form
• amount The raw amount in integer form
• balance_scalar The raw balance in scalar form
• amount_scalar The raw amount in scalar form
• balance_commitment The balance multiplied by a generator (mapped to a curve)
• amount_commitment The amount multiplied by a generator (mapped to a curve)
• expected_new_balance_commitment The new balance multiplied by a generator (mapped to a curve)
• generator The generator that is used to map values to the curve
• ranges Array of possible ranges of the amount

Return: True if transaction values are valid, false otherwise

Source code

#include "TransactionValidator.hpp"

using namespace nil::crypto3::algebra::curves;

// Function to create a point on the curve from the seed and TOTP
typename pallas::template g1_type<nil::crypto3::algebra::curves::coordinates::affine>::value_type GeneratePointFromSeedAndTotp(
    pallas::scalar_field_type::value_type seed,          // The base seed for TOTP as a field element
    pallas::scalar_field_type::value_type provided_totp, // Provided TOTP to validate
    typename pallas::template g1_type<nil::crypto3::algebra::curves::coordinates::affine>::value_type generator // The curve generator
)
{
    // Create a point on the curve using the seed
    typename pallas::template g1_type<nil::crypto3::algebra::curves::coordinates::affine>::value_type point = seed * generator; // Seed as a point

    // Use provided TOTP directly to create an offset
    typename pallas::scalar_field_type::value_type totp_offset = provided_totp; // Use by value

    // Adjust the point with TOTP offset
    point = point + ( totp_offset * generator ); // Add TOTP offset to the point

    return point; // Return the new point
}

bool ValidateTransactionValues(
    uint64_t                                                                                          balance,                         //
    uint64_t                                                                                          amount,                          //
    pallas::scalar_field_type::value_type                                                             balance_scalar,                  //
    pallas::scalar_field_type::value_type                                                             amount_scalar,                   //
    typename pallas::template g1_type<nil::crypto3::algebra::curves::coordinates::affine>::value_type balance_commitment,              //
    typename pallas::template g1_type<nil::crypto3::algebra::curves::coordinates::affine>::value_type amount_commitment,               //
    typename pallas::template g1_type<nil::crypto3::algebra::curves::coordinates::affine>::value_type expected_new_balance_commitment, //
    typename pallas::template g1_type<nil::crypto3::algebra::curves::coordinates::affine>::value_type generator,                       //
    std::array<pallas::scalar_field_type::value_type, MAX_RANGES>                                     ranges // Public parameter for upper bounds
)
{
    //TODO Arithmetic operations are not supported with scalar_field_type and curve multiplication is not supported with int
    // Initialize low bounds
    //typename pallas::scalar_field_type::value_type lowBounds = 0;

    // Determine the transfer amount range
    //for ( uint64_t i = 0; i < MAX_RANGES; i++ )
    //{
    // if ((amount_scalar >= lowBounds) && (amount_scalar < ranges[i])) {
    //     break; // Exit loop once the range is found
    // }
    //lowBounds = ranges[i]; // Update low bounds for the next range check
    //}
    //typename pallas::template g1_type<coordinates::affine>::value_type generator( X_generator, Y_generator );
    //The
    auto calculated_balance_point = balance_scalar * generator;
    auto calculated_amount_point  = amount_scalar * generator;


    if ( balance >= amount )
    {
        //TODO - Circuits don't allow for subtraction of scalars or point multiplication for integers.
        //auto new_balance = balance_scalar - amount_scalar;
        // Verify that the commitments match the expected values
        bool valid_balance_commitment = ( calculated_balance_point == balance_commitment );
        bool valid_amount_commitment  = ( calculated_amount_point == amount_commitment );
        //bool valid_new_balance_commitment = ( expected_new_balance_commitment == ( generator * new_balance ) );
        if ( valid_balance_commitment && valid_amount_commitment /* && valid_new_balance_commitment*/ )
        {
            return true;
        }
    }

    return false;
}

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Updated on 2026-04-13 at 23:22:46 -0700