Lohann

const webcrypto = require('crypto').webcrypto.subtle;

const enc = new TextEncoder();

function bytesToBase64url(bytes) {
    return Buffer.from(bytes).toString('base64url');
}

function jsonToBase64url(obj) {
    const bytes = enc.encode(JSON.stringify(obj));

Lohann

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

library ECDSA {
    /**
     * @notice Recovers the address for an ECDSA signature and message hash,
     * note that the hash must be prefixed with "\x19Ethereum Signed Message:\n{msg.length}"
     * @return address The address that was used to sign the message
     */

Lohann

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

contract Lottery {

    // PRICE PER TICKET
    uint256 constant TICKET_PRICE = (10 ** 18) / 100; // 0.01eth
    uint256 constant TICKET_OPTIONS = 30;
    uint256 constant OPTIONS_PER_TICKET = 3;

Lohann

// SPDX-License-Identifier: GPL-3.0

pragma solidity >=0.7.0 <0.9.0;

library Vote {
    uint256 constant BITS_PER_CANDIDATE = 5;
    uint256 constant BITMASK = (2**BITS_PER_CANDIDATE) - 1;

    // Storage Layout:
    // Voter (160bit) | size (5bit) | votes (5~90bit)