johnzweng

Verifying that I control the following Nostr public key: npub1pzglxuz9crnkzep8tf4z0f7qd0jckr7upar4cx447gck5nhgw3vsckv25p

johnzweng

A small ECDSA riddle.. ;-)

Message:

**********************************************************************

With this signed message, I, johnzweng, prove that I am NOT in possession of the private key of the signing address.

Not only do I claim this, no, this signed message proves this fact cryptographically beyond doubt. I have created this signature without outside help, yet I cannot know the private key of the signing address mentioned below.

johnzweng

import hashlib

# ECDSA Signature without private key

# An ECDSA signature without prior commitment to the signer's key
# does not prove that the signer knows the private key
# of the pubkey for which the signature validates.

# A short demonstration:

johnzweng

#!/bin/bash

# Description:
# Analyze testnet difficulty changes.
# This script iterates over the blocks and exports blockheight, time, mediantime,
# difficulty, bits and blockhash for all blocks around difficulty adjustments
# (5 blocks before and 5 blocks afterwards).
#
# Author: John Zweng,30.04.2024

johnzweng

New signs of Satoshi?

A few days ago, another sensationalist news story emerged, promising new clues regarding the true identity of Satoshi Nakamoto: Allegedly, an old message signed by Hal Finney had surfaced (published by Martin Shkreli in this blog post), suggesting that Paul Le Roux was the person behind the synonym of Satoshi Nakamoto.

I briefly highlight the facts surrounding this story:

The signed message:

Right away, yes indeed, a valid signed message has surfaced:

johnzweng

# The mystery around secpxxxk1 generation points :)
# -------------------------------------------------
#
# The SEC 2 familiy of elliptic curves are defined in https://www.secg.org/sec2-v2.pdf 
# and widely used in cryptography.
#
# The generation points G of these curves are defined in the standard paper without any nearer
# explanation how they were chosen. Interestingly the generation points (G) of all prime order 
# koblitz curves of the SEC 2 family (secp160k1, secp192k1, secp224k1, secp256k1) share some 
# unusual mysterious property.

johnzweng

Blockchain Rule Update Process

We recently rolled out two changes to the Bitcoin block acceptance rules (BIP16 and BIP30); this document records the lessons learned and makes recommendations for handling future blockchain rule changes.

Note: there are "soft" rule changes and "hard" rule changes. "Soft" changes tighten up the rules-- old software will accept all the blocks and transactions created by new software, but the opposite may not be true. "Soft" changes do not require the entire network of miners and merchants and users to upgrade or be left behind.

"Hard" changes modify the rules in a way that old, un-upgraded software consider illegal. At this point it is much, much more difficult (some might say impossible) to roll out "hard" changes, because they require every miner and merchant and user to upgrade.

Lessons Learned

johnzweng

#!/bin/bash

#
# This shell script allows you to check the Taproot signalling on your own
# Bitcoin fullnode (i.e. it does what https://taproot.watch/ does, but
# verified by your own node).
#
# Be a self-sovereign Bitcoiner!
#
# DON'T TRUST, VERIFY! :-)

johnzweng

#!/usr/bin/env bash

#
# Remap some keys on macOS (>=Sierra)
#
# Johnny, 2.11.2020
#

# Sources: based on https://gist.github.com/zbstof/6cba7d54e105cc5148c8a943d1581cad
#

johnzweng

#!/bin/bash

# require_password_on_next_unlock.sh:
# -----------------------------------
# Johannes Zweng, 8.11.2020
#
# Disable and enable global touch id unlock on macOS.
#
# After re-enabling unlock by touch-id, macOS will ask for
# password on the first unlock event (which is exactly what we want). :-)