Jonathan Gonzalez jonajosejg

Covert ECDH over secp256k1

If ECDH is used to establish a shared session secret for an encrypted connection, two elliptic curve points need to be transmitted (one in each direction) before encryption starts. In order to avoid being identifiable as a (specific) ECDH negotiation, ideally those two points are sent in a way that is indistinguishable from random.

This problem is easily addressed by using curves that support Elligator-style encodings: functions that encode a (subset of) elliptic curve points as sequences of bytes with no observable bias: (almost) every byte sequence corresponds to exactly one point, and the others correspond to none.

Unfortunately, no Elligator-style encoding is known for secp256k1.

	01000000 - version
	0000000000000000000000000000000000000000000000000000000000000000 - prevblock
	8a6be158deb38d5cc20aa8612ac303bb7ae59520d3b22213df5e88434f36b18e - merkleblock
	2d87ce6000000000000000000000000000000000000000000000000000000000 - withdrawalBundle
	0000000000000000000000000000000000000000000000000000000000000000 - mainchainBlock
	00000000 - timestamp
	ffff7f20 - bits
	02000000 - nonce
	01 - number of tx
	01000000 - version

	/*!
	* sidechain.js - a sidechain template for bitcoin
	* Copyright (C) 2023, Jonathan Gonzalies (MIT License).
	* https://github.com/rojii/sidechain
	*/

	'use strict';

	const assert = require('bsert');
	const layout = require('./blockchain/layout');



	'use strict';

	const assert = require('bsert');
	const EventEmitter = require('events');
	const WEB3 = require('web3-eth');
	const {endpoint} = require('./constants');

	/**

	'use strict';

	const assert = require('assert');
	const bcoin = require('bcoin');

	const MTX = bcoin.MTX;
	const Keyring = bcoin.wallet.WalletKey;
	const Outpoint = bcoin.Outpoint;
	const Script = bcoin.Script;
	const Coin = bcoin.Coin;

	/* eslint-env mocha */

	'use strict';

	const {NodeClient, WalletClient} = require('../lib/client');
	const assert = require('bsert');
	const consensus = require('../lib/protocol/consensus');
	const FullNode = require('../lib/node/fullnode');
	const Network = require('../lib/protocol/network');
	const Mnemonic = require('../lib/hd/mnemonic');

	var alnilam = Number.EPSILON * illai * 0.4503599627370496

	var e = Number.EPSILON * 2 ** 52;

	var pop8tab = [256]uint8{
	0x00, 0x01, 0x01, 0x02, 0x01, 0x02, 0x02, 0x03, 0x01, 0x02, 0x02, 0x03, 0x02, 0x03, 0x03, 0x04,
	0x01, 0x02, 0x02, 0x03, 0x02, 0x03, 0x03, 0x04, 0x02, 0x03, 0x03, 0x04, 0x03, 0x04, 0x04, 0x05,
	0x01, 0x02, 0x02, 0x03, 0x02, 0x03, 0x03, 0x04, 0x02, 0x03, 0x03, 0x04, 0x03, 0x04, 0x04, 0x05,
	0x02, 0x03, 0x03, 0x04, 0x03, 0x04, 0x04, 0x05, 0x03, 0x04, 0x04, 0x05, 0x04, 0x05, 0x05, 0x06,
	0x01, 0x02, 0x02, 0x03, 0x02, 0x03, 0x03, 0x04, 0x02, 0x03, 0x03, 0x04, 0x03, 0x04, 0x04, 0x05,
	0x02, 0x03, 0x03, 0x04, 0x03, 0x04, 0x04, 0x05, 0x03, 0x04, 0x04, 0x05, 0x04, 0x05, 0x05, 0x06,
	0x02, 0x03, 0x03, 0x04, 0x03, 0x04, 0x04, 0x05, 0x03, 0x04, 0x04, 0x05, 0x04, 0x05, 0x05, 0x06,
	0x03, 0x04, 0x04, 0x05, 0x04, 0x05, 0x05, 0x06, 0x04, 0x05, 0x05, 0x06, 0x05, 0x06, 0x06, 0x07,
	0x01, 0x02, 0x02, 0x03, 0x02, 0x03, 0x03, 0x04, 0x02, 0x03, 0x03, 0x04, 0x03, 0x04, 0x04, 0x05,

	[
	["Format is: [[wit..., amount]?, scriptSig, scriptPubKey, flags, expected_scripterror, ... comments]"],
	["It is evaluated as if there was a crediting coinbase transaction with two 0"],
	["pushes as scriptSig, and one output of 0 satoshi and given scriptPubKey,"],
	["followed by a spending transaction which spends this output as only input (and"],
	["correct prevout hash), using the given scriptSig. All nLockTimes are 0, all"],
	["nSequences are max."],

	["", "DEPTH 0 EQUAL", "P2SH,STRICTENC", "OK", "Test the test: we should have an empty stack after scriptSig evaluation"],
	[" ", "DEPTH 0 EQUAL", "P2SH,STRICTENC", "OK", "and multiple spaces should not change that."],