Showing posts with label Bitcoin. Show all posts
Showing posts with label Bitcoin. Show all posts

Friday, April 25, 2014

The bitcoin logo
The bitcoin logo (Photo credit: Wikipedia)




There is no greater point of weakness in Bitcoin than a 51% attack. A fifty-one percent attack can shut down the network. This video discusses all the attack vectors available to an attacker. And there are many, even worse, the devastation available is catastrophic. While a 51% attack doesn't appear to offer a lot of financial gain, history is not just made up of rational actors.

James goes through Transaction Denial of Service, Selfish Mining, Monopoly Mining and Double Spending, finding fault with proposed patches and solutions. It is not pretty. As Gavin Andresen says, if someone was able to run a 51% attack "that would be bad". We agree. It would be very bad.

At the end of the video we discuss protocol changes that would make an attack much more difficult. We highlight Proof of Stake as a fallback algorithm. The biggest advantage is that POS provides a MUCH higher cost to the attacker for perpetrating such an attack. That, would be good.

In part one, we go through a cost analysis of the current hardware needed to launch a successful 51% attack to get a better picture how much it might cost. Unfortunately, the numbers are lower than expected, and most of the previously published values come in three to fifty times higher than actuality. In part two we will talk more about what an attacker might be able to do (double spending is not the worse tool at their disposal) and we prod at some possible solutions. Stay tuned


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Thursday, April 17, 2014

Bitcoin 101 - The Nightmare of a 51% Attack - Part 1 - Calculating The Costs

The bitcoin logo
The bitcoin logo (Photo credit: Wikipedia)



Proof of work is a new technology, and it has amazingly protected Bitcoin for five plus years. Still, there may be no greater point of weakness in Bitcoin. While a 51% attack doesn't appear to offer a lot of financial gain, monetary gain may not be the motive of the attacker. In part one, we go through a cost analysis of the current hardware needed to launch a successful 51% attack to get a better picture how much it might cost. Unfortunately, the numbers are lower than expected, and most of the previously published values come in three to fifty times higher than actuality. In part two we will talk more about what an attacker might be able to do (double spending is not the worse tool at their disposal) and we prod at some possible solutions. Stay tuned.

Welcome to WBN's Bitcoin 101 Blackboard Series -- a full beginner to expert course in bitcoin. We hope you enjoy. And remember the official WBN launch is coming up : July 1st, 2014.
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Tuesday, April 15, 2014

Sunday, March 23, 2014

Friday, March 21, 2014

Bitcoin 101 - Multi-Signature Addresses pt2 - Spending, Protocol & Coding

The bitcoin logo
The bitcoin logo (Photo credit: Wikipedia)




This part two of a two part series on muti-signature addresses and wallets. This is important technology for massively improving bitcoin security. In part one we generated a multisig address/wallet. In this part, we'lll walk you through all the steps necessary to spend the funds, going line by line through some simple python code and generating a payment in bitcoind.

In many ways, multisig addresses are the answer to most of bitcoin's concerns and fears of theft. And now its time to scale up massive implementation for them. Originally introduced into the bitcoin client a few years ago, multisignature addresses massively more secure than regular ones. Their adoption by all wallet manufacturers is coming. But, for you techies and voyeurs, we'll jump inside the ideas of multi-sig and even program the stuff. Hope you enjoy.
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Tuesday, March 18, 2014

Bitcoin 101 - Multi-Signature Addresses pt1 - Coding This Major Security Improvement

The bitcoin logo
The bitcoin logo (Photo credit: Wikipedia)



Just like the Wright brothers, on those first flights at Kitty Hawk, didn't concern themselves that much with landing. And improvements like anti-lock brakes and seat belts help protect passengers in cars. Bitcoin is now in that 'second phase' where security is becoming massively important. Fortunately, because the currency is programmable, anything is really possible. Originally introduced into the bitcoin client a few years ago, multisignature addresses massively more secure than regular ones. Their adoption by all wallet manufacturers is coming. But, for you techies and voyeurs, we'll jump inside the ideas of multi-sig and even program the stuff. Hope you enjoy.


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Sunday, March 2, 2014

Bitcoin 101 - Merkle Roots and Merkle Trees - Bitcoin Coding and Software - The Block Header

The bitcoin logo
The bitcoin logo (Photo credit: Wikipedia)



Most people on earth have never even heard of Merkle roots. But bitcoin programmers deal with them every day. This is old school technology in terms of software, but still very important in terms of security and data management. In this video James will walk you into the world of Merkle roots and Ralph Merkle, who invented this technology in the late 1980s. If you like seeing actual coding examples, your in luck. James starts incorporating actual python examples...after all, would you want to listen to Car Talk and not want to hear about a muffler? Enjoy.


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