Reawaken interest in Chain-Archeology
Posted by SDLerner in Uncategorized on April 3, 2014
These days I saw some reawaken interest in searching for patterns in early mined blocks by Taras. Well, last month media circus around Dorian Satoshi may have contributed. I welcome Taras to the chain-archeology field, and I hope he does it responsibly. While reading his posts I remembered two chain-archeology techniques [1] that I planned […]
The people behind Bitcoin
Posted by SDLerner in Uncategorized on April 1, 2014
A personal story Three years ago I was introduced to Bitcoin by a friend, and I was immediately fascinated by the protocol design. But since I’m a computer scientist and I was passionate for cryptography and security, the first thing I did was try to break Bitcoin. But the quality of source code was quite […]
MinCen: A new protocol to achieve instant payments
Posted by SDLerner in Uncategorized on March 20, 2014
Every day we discover new advantages of decentralized systems and peer-to-peer networks . Well designed P2P systems, provide greater resilience against attacks and accidental disruptions. Nevertheless decentralization comes with a price: consensus must be reached by voting or by proof-of-work, and both solutions tend to be slower than traditional centralized decisions. Instant payments requires instant […]
The re-design of the Bitcoin block header
Posted by SDLerner in Uncategorized on March 18, 2014
Today is the third time I find an attack to the way Bitcoin uses SHA-256 to perform mining. Two of the attacks belong to a new family of attacks that involve terribly technical details about the inner workings of SHA-256. These are attacks that may impact on Bitcoin probably not before 5 years, and they […]
Safe merged-mining and the Bitcoin’s Karma
Posted by SDLerner in Uncategorized on February 20, 2014
In this post I will depart shortly from my classical technical viewpoint and enter the quicksands of opinions. But I’ll come back, don’t worry. The idea of the proof-of-work powered block-chain, while powerful, has lead us to a situation where many people sees Bitcoin mining as a wasteful and vicious activity. Articles against Bitcoin mining […]
25-second irreversible confirmations for instant payments
Posted by SDLerner in Uncategorized on February 17, 2014
Recently there has been a race towards lower block intervals for PoW block-chain based cryptocurrencies. First there was Bitcoin with a 10 minute interval, then was LiteCoin using a 2.5 interval, then was DogeCoin with 1 minute, and then QuarkCoin with just 30 seconds. This reminds me a joke in a comedy movie where there […]
Changes in Ethereum scripting language
Posted by SDLerner in Uncategorized on February 5, 2014
Today I read that Ethereum is abandoning a crypto-rich instruction set in favor of a reduced generic instruction set. This shocked me, because I liked Ethereum instruction set design just as it was. The main argument given by VButerin is that this change makes the instruction set more compatible with future cryptographic algorithms, by preferring […]
Ethereum “Dagger” PoW function is flawed
Posted by SDLerner in Uncategorized on January 17, 2014
Ethereum is a new cryptocurrency that attempts to provide a Turing complete scripting system for cryptocurrencies and other complex contracts. It may seem to the newcomers that it is a radical new design, but it is not. The first coin to propose such a system was QixCoin (a Turing complete coin) and it was published […]
Strict memory hard hash functions
Posted by SDLerner in Uncategorized on December 31, 2013
Strict memory hard functions are an extension of memory hard functions such that a slight reduction in the memory available for computation, compared to a predefined optimal memory size, makes the function evaluation exponentially slower or infeasible. The main application of strict memory hard functions is to prove a certain amount of memory is used […]
RSALX digital signature scheme
Posted by SDLerner in Uncategorized on December 18, 2013
When I posted about RSAL in my last post I was also thinking of a variant scheme that allows some pre-computation. I spent some time (minutes) evaluating its security and now I’m convinced that it’s secure :). Here it is: The RSALX Digital signature Scheme PrecomputeSign() →< A, a, t1, … , t2^d > Chose […]
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