Bitcoin design analyst


Re-mining Patoshi Blocks for Dummies

In my previous article I discussed re-mining with a lot of technical details. A few days ago, a non-technical friend (yes, I have a few of those) asked me what was re-mining all about. I tried hard to find an analogy in the real world that compares to re-mining Bitcoin blocks. My first attempt to […]

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The Patoshi Mining Machine

One of the topics that has been debated endlessly is what kind of hardware Satoshi used for mining. Some people argue he only needed a single computer using the latest generation of Intel processors available in 2009, using a CPU miner with SSE2-optimizations and multi-threading. Others argue that he had about 50 low-end networked computers. […]

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A New Mystery in Patoshi Timestamps

Patoshi is the name I gave to the prominent miner that in 2009-2010 mined about 1.1M bitcoins, and that some people associate with Satoshi Nakamoto. Last time I wrote about Patoshi was in April, 2019. At that time, I posted in order to clarify what we know, technically, about how Patoshi mined. Impossible was for […]

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An overwhelming task

By Sergio Lerner. Something amazing happened to me. I was leaving a meeting to enter another, disappointed for not being able to gather time to write and preparing for the adrenaline rush that I get when entering a meeting without any notion of the subject in question, when the secretary approached and warned me that […]

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Armadillo: More Consensus Security for RSK

Last month I published an article on RSK Labs’s blog on how merge-mining works on the RSK sidechain. In this short article, I will deepen[1] the issue of the security of merge-mining RSK, and show how RSK’s security has increased after the last network upgrade. Now RSK merge-mining security could reach a level of security […]

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The Return of the Deniers and the Revenge of Patoshi

Synopsis: In this article I will discuss what we know about the early Bitcoin blocks. Also I will present a new strong argument that a single miner mined 22k blocks. Finally I’ll introduce,  new website that shows a cool visualization of early blocks. The last time I wrote about Satoshi I thought it would be […]

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Simple change to the Bitcoin MERKLEBLOCK command to protect from Leaf-Node weakness in Transaction Merkle Tree

Recently a fix to the Bitcoin Merkle tree design weakness in the RSK’s bridge was built by making invalid SPV proofs whose internal hashes are valid Bitcoin transaction. While this solves the problem, it is by no means a “clean” solution: it creates false-negative cases (with very low probability)  and it reduces verification efficiency. While […]

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Leaf-Node weakness in Bitcoin Merkle Tree Design

  This document describes a weakness in Bitcoin Design that reduces the security of SPV proofs and therefore SPV Wallets.  The weakness was discovered by me on August 2017, but during the responsable disclosure process I learnt it was previously known by some prominent members of the Bitcoin Core team. Using this weakness an attacker […]

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Blockchain State Storage Rent Revised

(This post is an updated re-post of a previous post in RSK blog) In a nutshell, storage rent is a fee users pay in order to have their accounts, contracts and memory live on the network at any time, so their data can be accessed fast and at a low cost. Storage rent does not fulfill any purpose in […]

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Scaling Bitcoin to One Billion Users, Part I

The most important comparative properties of cryptocurrencies are decentralization, scalability, confidentiality, stability, usability, security.  But scalability is always in conflict with the rest of the properties. To scale higher, some blockchains sacrifice security, usability or privacy. For example, Bitcoin sacrifices some security because it lacks stateful smart-contracts, so users cannot set daily withdrawal limits or […]

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