Posts Tagged Bitcoin
Re-mining Patoshi Blocks for Dummies
Posted by SDLerner in Uncategorized on September 3, 2020
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 […]
The Patoshi Mining Machine
Posted by SDLerner in Uncategorized on August 22, 2020
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. […]
Scaling Bitcoin to One Billion Users, Part I
Posted by SDLerner in Uncategorized on January 18, 2018
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 […]
A Bitcoin transaction that takes 5 hours to verify
Posted by SDLerner in Uncategorized on January 8, 2017
In 2013 I found a Bitcoin transaction that takes 3 minutes to verify (CVE-2013-2292) related to O(N^2) hashing in signatures. Since then, the O(N^2) argument has popped up in many contexts, mainly in discussions about a block size increase. Now the problem is partially solved by Segwit. During January 2016 I tried to beat the […]
Proof of unique blockchain storage revised
Posted by SDLerner in Uncategorized on September 16, 2015
In this post I describe a new way to for a node in the Bitcoin blockchain to prove to its peers that it is storing a copy of the blockchain. The core primitive that enables this protocol this is the Asymmetric-Time Function (ATF). You won’t get much info by googling ATF since I coined that term […]
Faster SHA-256 ASICs using carry reduced adders
Posted by SDLerner in Uncategorized on February 17, 2015
The core part of Bitcoin mining is performing a double SHA-256 hash digest and comparing the result against the target. Two years ago, in 2013, the first Bitcoin ASIC miners appeared on the market. Since then, mining ASIC technology advanced both in terms of the manufacturing technology (the node) and in terms of design, to […]
The Bitcoin Freeze on Transaction Attack (FRONT)
Posted by SDLerner in Uncategorized on October 5, 2014
Two month passed since my last post and the reason is I’ve been terribly busy working for Coinspect and also helping with Bitcoin Core security. A rainy Sunday evening is a great moment to write, so here is my new post, with some new thoughts. People are trying to understand the security guarantees Bitcoin provides. […]
Blockpad: Improved Proof-of-work function with decentralization incentives
Posted by SDLerner in Uncategorized on July 5, 2014
A few posts ago I presented BlockPow, an example of a proof of work function that practically reduces the incentives for users to join mining pools. The shorter the block interval, the best it works. Let’s first summarize the idea behind BlockPow: if a miner tries to join a pool, then he incur in overhead […]
Preventing Geographical Centralization of Cryptocurrency Mining with the LIMIO protocol
Posted by SDLerner in Uncategorized on July 4, 2014
There has been much discussion recently about how to prevent mining pools. There are theoretical and practical approaches. Nevertheless preventing mining pools is not the same as preventing geographical centralization. Mining pools incentives are: Reduce payoff variance. Reduce resource usage. Normally Bitcoin node would require more resources (memory,disk, bandwidth) than a pooled miner. Reduce exposition to […]
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