@tokamak-zk-evm/synthesizer
Version:
Tokamak zk-EVM Synthesizer - Processes Ethereum transactions into wire maps for Tokamak zk-SNARK proof generation
63 lines • 2.09 kB
JavaScript
import { equalsBytes } from "@synthesizer-libs/util";
import { BLS_GAS_DISCOUNT_PAIRS } from './constants.js';
const ZERO_BYTES_16 = new Uint8Array(16);
/**
* Calculates the gas used for the MSM precompiles based on the number of pairs and
* calculating in some discount in relation to the number of pairs.
*
* @param numPairs
* @param gasUsedPerPair
* @returns
*/
export const msmGasUsed = (numPairs, gasUsedPerPair) => {
const gasDiscountMax = BLS_GAS_DISCOUNT_PAIRS[BLS_GAS_DISCOUNT_PAIRS.length - 1][1];
let gasDiscountMultiplier;
if (numPairs <= BLS_GAS_DISCOUNT_PAIRS.length) {
if (numPairs === 0) {
gasDiscountMultiplier = 0; // this implicitly sets gasUsed to 0 as per the EIP.
}
else {
gasDiscountMultiplier = BLS_GAS_DISCOUNT_PAIRS[numPairs - 1][1];
}
}
else {
gasDiscountMultiplier = gasDiscountMax;
}
// (numPairs * multiplication_cost * discount) / multiplier
return (BigInt(numPairs) * gasUsedPerPair * BigInt(gasDiscountMultiplier)) / BigInt(1000);
};
/**
* BLS-specific zero check to check that the top 16 bytes of a 64 byte field element provided
* are always zero (see EIP notes on field element encoding).
*
* Zero byte ranges are expected to be passed in the following format (and so each referencing
* 16-byte ranges):
*
* ```ts
* const zeroByteRanges = [
* [0, 16],
* [64, 80],
* [128, 144]
*
* ]
* ```
*
* @param opts
* @param zeroByteRanges
* @param pName
* @param pairStart
* @returns
*/
export const leading16ZeroBytesCheck = (opts, zeroByteRanges, pName, pairStart = 0) => {
for (const index in zeroByteRanges) {
const slicedBuffer = opts.data.subarray(zeroByteRanges[index][0] + pairStart, zeroByteRanges[index][1] + pairStart);
if (!(equalsBytes(slicedBuffer, ZERO_BYTES_16) === true)) {
if (opts._debug !== undefined) {
opts._debug(`${pName} failed: Point not on curve`);
}
return false;
}
}
return true;
};
//# sourceMappingURL=util.js.map