Bitcoin Explanation - Schneier on Security

Bitcoin Civil War (the bright sides)

It will be interesting to see how the next couple of months play out. Whatever happens, there are a couple of positive sides to the situation.
For one, we will see if it is possible to change the rules of the Bitcoin network even against considerable resistance.
The Japanese Constitution has never been amended. But it is very clear what is necessary to amend it. Article 96 of the Constitution states the requirements.
The Bitcoin network has never been challenged by an internal faction in the way it is now. In contrast to the Japanese Constitution, it is not very clear what is needed to push through the block size extension the Bitcoin Unlimited camp wants.
So if they succeed in their attempt, we will have a reference case what is needed to change the protocol against substantial resistance. If they fail, we will have a reference case as well, showing that the failed level of support was not enough.
This civil war will also be an interesting case to study when preparing for war with outside attackers. There has been speculation about "51%-attacks" before. But as far as I know, no one has ever actually pulled off a 51%-attack against the Bitcoin network.
In the course of this civil war, that may change. I hear that Peter Rizun, one of the supporters of Bitcoin Unlimited, is advocating for using hash power to shut down the original Bitcoin chain after a fork, mining empty blocks on that chain.
If that happens, that would be an excellent test case. A highly motivated, well-funded adversary trying to shut down the Bitcoin blockchain has not happened yet in real life.
If such an attack happens, and the Bitcoin blockchain survives it one way or another, that would be real-life proof of its resiliency.
Since all of the value of the Bitcoin blockchain comes from this resiliency against attack and the trust created, surviving such a test would be proof of its value. An eight year track record of unbroken service is valuable, but extending it defeating serious attacks shows even more value.
All cryptography has value only as far as people actually try to break it and fail (Schneier's law). It follows that attacks on the Bitcoin network like the one Rizun wants to happen are a good thing.
We also may get a short-term increase in block space (if the Bitcoin Unlimited faction wins the civil war).
Again, interesting times for the Bitcoin network.
submitted by Karl-Friedrich_Lenz to btc [link] [comments]

Cryptographic reviews of bitcoin?

I'm searching for informed bitcoin reviews, infact I haven't the knowledge to complitely understand and value its security, the only cryptographer that I read that write on this is Bruce Schneier, that wrote this:
"I'm often asked what I think about bitcoins. I haven't analyzed the security, but what I have seen looks good. The real issues are economic and political, and I don't have the expertise to have an opinion on that."
experienced people reviews of bitcoin
1 - Bruce Schneier
2 - Dan Kaminsky
submitted by pietrod21 to Bitcoin [link] [comments]

Writing a book on Bitcoin and blockchain technology, and I'm looking for particularly illuminating arguments for why it's taken as a given that a hostile attacker can't mass enough computing power to perform a 51% attack. Any help appreciated!

Hey all! As the title says, I'm working on a book about Bitcoin, blockchain tech, and cryptocurrencies. The section I'm working on now is about how the blockchain provides such robust security.
Bitcoin takes as a given that honest nodes will always control a majority of the computing power. To a reader who is unfamiliar with the space, though, this seems like an unsubstantiated claim. I have a vague understanding of why this is true, but I can't find a way to express it in a way that would be convincing to a layperson. Is anyone aware of any particularly illustrative examples of why this assumption is taken for granted among the Bitcoin community?
As an example of what I'm looking for, here is an illustration I'm using to demonstrate the security of a single Bitcoin private key, adapted from Bruce Schneier's writing (ctrl+f "second law of thermodynamics"):
First, recognize that a specific consequence of the second law of thermodynamics is that there is a minimum energy required to change a single binary bit of information.
Now suppose you were able to harness the entire energy output of the sun only to power a specially designed computer, whose job is to count through private keys, in the hopes of finding one corresponding to a public key that held Bitcoins.
Using a bit of math, you'll find that a perfectly efficient computer can count through 2178 values given the sun's entire annual energy output. If we divide this value into the number of possible private keys, 2256, we find that this hypothetical computer would only be able to count through 0.0000000000000000000003% of the total number of possible private keys, given the entire annual energy output of the sun.
Furthermore, this is just counting, and doesn't actually include the monumentally more complex task of actually checking each private key to see if it corresponds to a “winning” public key. So in the 0.0000000000000000000003% chance this computer did happen across a lucky private key, it wouldn't even know it.
Schneier closes with this: “These numbers have nothing to do with the technology of the devices; they are the maximums that thermodynamics will allow. And they strongly imply that brute-force attacks against 256-bit keys will be infeasible until computers are built from something other than matter and occupy something other than space.”
submitted by coinop-logan to Bitcoin [link] [comments]

Bitcoin Mining 2019 - Should We Mine Bitcoin? - YouTube Bitcoin to 6k!? Why? China Wants Control of BTC!! Security in the World-Sized Web Current Bitcoin Price - March 25th 2020 Quanto vale Bitcoin adesso ?  Blockchain Caffe

Bruce Schneier is a security technologist who teaches at the Harvard Kennedy School. ... you quickly realize that there is much more hype than value. Blockchain solutions are often much worse than ... There's No Good Reason to Trust Blockchain Technology. Bruce Schneier; Wired; February 6, 2019; In his 2008 white paper that first proposed bitcoin, the anonymous Satoshi Nakamoto concluded with: “We have proposed a system for electronic transactions without relying on trust.”He was referring to blockchain, the system behind bitcoin cryptocurrency.The circumvention of trust is a great ... I was a bit shocked with such a radical statement coming from him. In 2016, Bruce Schneier participated in a Blockchain Workshop in Nairobi where he gave a keynote.The video of the talk is here ... About Bruce Schneier. I am a public-interest technologist, working at the intersection of security, technology, and people. I've been writing about security issues on my blog since 2004, and in my monthly newsletter since 1998. I'm a fellow and lecturer at Harvard's Kennedy School and a board member of EFF. This personal website expresses the ... Security expert Bruce Schneier once ruled out an attempt to crack a 256-bit key, of the type used by Bitcoin, by referring to the laws of physics: such is the magnitude of the problem. Even an impracticably large computer consuming all the energy outputted by the sun couldn't count the number of possible combinations in several decades.

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Bitcoin Mining 2019 - Should We Mine Bitcoin? - YouTube

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