Lohann’s gists

Lohann / Serialization.sol

Created June 30, 2022 14:29

Solidity encode/decode

	// 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)

Lohann / Lottery.sol

Last active July 10, 2022 15:15

Example of a simple lottery smart-contract written in solidity

	// 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 / UnidirecionalPaymentChannel.sol

Last active July 24, 2022 14:57

Example of Unidirecional Payment Channel in solidty

	// 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 / RS256-jwt.js

Created April 26, 2023 02:42

	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 / github-device-code-grant.js

Created April 26, 2023 23:12

	// "dependencies": {
	// "axios": "^1.3.6"
	// }
	const axios = require('axios');

	const CLIENT_ID = '<client_id_aqui>';

	async function run(token) {
	console.log(token);
	}

Lohann / rust_rsa_accumulator.rs

Last active October 18, 2024 00:46

Basic implementation of RSA Accumulator in rust

	// [dependencies]
	// blake2b_simd = "1.0.1"
	// num-bigint = "0.4.3"
	// num-integer = "0.1.45"
	// num-prime = { version = "0.4.3", features=["num-bigint"] }
	// num-traits = "0.2.15"

	use blake2b_simd;
	use num_bigint::{BigInt, BigUint, Sign};
	use num_integer::Integer;

Lohann / frost_dkg.py

Last active October 18, 2024 21:36

Threshold Signatures implementation based on FROST using schorr signatures over the RSA group

	import hashlib
	from random import SystemRandom
	from collections import namedtuple

	'''
	FROST: Flexible Round-Optimized Schnorr Threshold Signatures

	Implementation based in this paper:
	https://eprint.iacr.org/2020/852.pdf
	'''

Lohann / bip44.py

Created February 14, 2024 22:16

	"""
	-- requirements.txt
	bip_utils==2.9.1
	mnemonic==0.21
	"""
	from mnemonic import Mnemonic
	from bip_utils import Bip44, Bip44Changes, Bip44Coins

	mnemonic = "bottom drive obey lake curtain smoke basket hold race lonely fit walk"
	passphrase = "password here"

Lohann / Sqrt.opcodes

Created March 26, 2024 05:44

	// Gas efficient SQRT method, computes floor(sqrt(x)).
	// Constant gas cost of 355
	//
	// For testing use this tool: https://www.evm.codes/playground?fork=cancun
	// Author: Lohann Ferreira
	PUSH0
	CALLDATALOAD
	PUSH1 1
	DUP2

Lohann / InjectCode.sol

Last active May 17, 2024 14:29

	// SPDX-License-Identifier: GPL-3.0

	pragma solidity >=0.7.0 <0.9.0;

	/**
	* Workaround example on how to inject and execute arbitrary bytecode in solidity contract
	* Currently only YUL supports verbatim: https://github.com/ethereum/solidity/issues/12067
	* But you cannot import Solidity code in YUL, or YUL code in solidity, so this workaround is necessary.
	* It works as long the byte sequence `0x7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F7F00` appear in the runtime code.
	*

Lohann Paterno Coutinho Ferreira Lohann