arowser

Stealth Addresses, Transactions and Messages

Normal bitcoin addresses cannot be published in public without losing all privacy, since all transactions to that address can be seen by anybody. Stealth addresses let us publish an address in public which can be used by payers to derive a new address that the payee has access to, but no one else knows is associated with the stealth address. The trick is that the payer must use a nonce to derive the address paid to, and this nonce must be delivered to the payee so they know how to recover the funds. This nonce can be delivered in the transaction, so that no separate channel is required to communicate the nonce.

The same technology can also be used to construct new public keys to send encrypted messages to.

We will discuss four methods:

The simplest form of stealth addresses, which has some drawbacks that can improved upon.

Optimizing New Block Messages

Motivation

The network message used to announce the discovery of a new block is inefficient, and that inefficiency translates indirectly into higher transaction fees for users. The dominating cost for a miner to include an extra transaction in their block is the incremental "orphan cost", which is dependent on how quickly the block is propagated across the peer-to-peer network.

Network/miner fee policy migration plan

Introduction

Changing the fees required for transactions to be relayed across the network and/or accepted by miners into their blocks requires care; policy mis-matches can result in users' transactions never confirming, either because they never reach a miner (they are not relayed) or because they are rejected by miners.

I have been working on simplifying the transaction fee rules for the 0.9 release; this document is intended to capture all of the details needed to make that transition as smoothly as possible.

The general idea is to make sure the transaction-generating code (the wallet code) is conservative, and generates transactions compatible with the previous version's rules. The relay and mining code is changed more aggressively, to anticipate future releases.

	#!/usr/bin/env python2
	"""
	Author: takeshix <[email protected]>
	PoC code for CVE-2014-0160. Original PoC by Jared Stafford ([email protected]).

	Supportes all versions of TLS and has STARTTLS support for SMTP,POP3,IMAP,FTP and XMPP.
	"""

	import sys,struct,socket
	from argparse import ArgumentParser

	CREATE OR REPLACE FUNCTION public.json_append(data json, insert_data json)
	RETURNS json
	IMMUTABLE
	LANGUAGE sql
	AS $$
	SELECT ('{'\|\|string_agg(to_json(key)\|\|':'\|\|value, ',')\|\|'}')::json
	FROM (
	SELECT * FROM json_each(data)
	UNION ALL
	SELECT * FROM json_each(insert_data)

	package main
	import (
	"log"
	"github.com/piotrnar/gocoin/blockdb"
	"github.com/piotrnar/gocoin/btc"
	"encoding/hex"
	)

	func main() {
	// Set real Bitcoin network

	import re
	import hashlib
	import base58
	from pycoin.ecdsa import generator_secp256k1, public_pair_for_secret_exponent

	def bytetohex(byteStr):
	return ''.join( [ "%02X" % x for x in byteStr ] ).strip()

	litecoin = [b"\x30", b"\xb0"]
	bitcoin = [b"\x00", b"\x80"]

	import simplejson as json
	import lxml

	class objectJSONEncoder(json.JSONEncoder):
	"""A specialized JSON encoder that can handle simple lxml objectify types
	>>> from lxml import objectify
	>>> obj = objectify.fromstring("<Book><price>1.50</price><author>W. Shakespeare</author></Book>")
	>>> objectJSONEncoder().encode(obj)
	'{"price": 1.5, "author": "W. Shakespeare"}'
	"""

	# coding=UTF-8
	from __future__ import division
	import re

	# This is a naive text summarization algorithm
	# Created by Shlomi Babluki
	# April, 2013


	class SummaryTool(object):

	<!DOCTYPE html>
	<html>
	<head>
	<title></title>
	<script src="/jquery.js"></script>
	<script src="/jsbn.js"></script>
	<script src="/rsa.js"></script>
	<script src="/sha1.js"></script>
	<script type="text/javascript">
	function encrypt() {