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). :-)

johnzweng

First technical view on "Libra":

Author: Johannes Zweng (johannes@zweng.at) Date: 19.6.2019

Notes:

• Will be a new blockchain, not based on an existing blockchain
• Permissioned blockchain (not everybody can be a validator)

johnzweng

Verifying my Blockstack ID is secured with the address 1FemuY4GdW1ToSfF4P6Nex5zR8N2vRZSda https://explorer.blockstack.org/address/1FemuY4GdW1ToSfF4P6Nex5zR8N2vRZSda

johnzweng

Status of CUDA 9 installation on my GCE instance:

Ubuntu version:

> lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 16.04.5 LTS
Release:    16.04
Codename:    xenial