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POS: Prove Your Steak on the Blockchain

October 28, 2016
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Introduction The first thing that came to mind when I saw “PoS” was Point of Sale. EFTPOS is very popular in New Zealand and Australia but this has nothing to do with collecting payment. It also has nothing to do with proving how much steak you can eat. That would be interesting though! PoS stands for Proof of Stake and is one way to achieve consensus on the blockchain. Other ways to achieve consensus on the blockchain include (but not limited to): Proof of Work Proof of Activity Proof of Capacity Proof of Storage Proof of Work (PoW) is currently the most common and is being used on the bitcoin blockchain. To understand more about PoW read this. Proof of Stake (PoS) has made some noise in recent times in particular with Ethereum looking at moving away from PoW to PoS. Before we look at PoS, first let’s see why we need it. Consensus In a distributed, trustless computing network, there needs to be a way for a collection of machines to come to an agreement of facts. In a blockchain, any participating node on the network can create a candidate block very easily by obtaining the relevant software and verifying the transactions […]
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Neat paper on Blockchains, Smart Contracts and IoT

October 2, 2016
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Here is a link to a neat paper called Blockchains and Smart Contracts for the Internet of Things by Konstantinos Christidis, (Graduate Student Member, IEEE) and Michael Devetsikiotis, (Fellow, IEEE). http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7467408 It does a great job explaining some of the basics of blockchains and smart contracts before getting into lots of possible applications. If the above link is broken, here is another link: blockchains-and-smart-contracts-for-the-iot
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IBM Blockchain for developers

September 15, 2016
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Introduction I had heard about IBM donating 44k lines of code to the Hyperledger project a while ago and was curious interested to see what IBM had to offer in the blockchain space. IBM has a neat little learning path to understand more about blockchain technologies. It’s a free self paced course that takes a few hours (not really the 6 that it says) and does a pretty good job at explaining IBM, blockchain and the Hyperledger. What was good The course was professionally done with goals, quizzes at the end of each course, videos and notes and the best part was the hands on development environment Bluemix. It’s only a 30 day trial but no credit card was required. The content was good where IBM introduced terminology such as “world state” to mean the state of the blockchain or the ledger and “blockchain fabric” to mean blockchain framework. Above is a neat diagram of the various blockchain components in the IBM Hyperledger stack. The above screenshot shows the 1 click blockchain deployment process within Bluemix where everything is set up automatically. The car leasing demo was interesting behind the scenes but the front end interface was just like any […]
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Learning how to secure the blockchain

September 4, 2016
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It has been a very busy few weeks since my first trip to the US. As part of my STEM contribution, I was looking for old mining boards to first learn how mining works and then to share this knowledge with the younger generation. I put a shout on the community forums a while ago and a very generous person offered one of his boards. It would have cost a lot to send it to NZ so I ended up picking it up while in the US. From attending various meet ups and talking with all sorts of people, everyone wants “in” on blockchain applications and smart contracts. That is because it’s the buzz at the moment. The good old bitcoin cryptocurrency has been left in the dust. There is also the negative connotation that surrounds bitcoins such as “it’s used for buying drugs” and “it’s a speculative currency”. Whilst these maybe true, understanding components of how bitcoin works provides an excellent foundation to build upon. One example is analysing what is inside a blockchain. Another example is that of securing the blockchain, aka mining. Currently the main algorithm used to secure transactions on the blockchain is Proof of Work. It has […]
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Going POW on the Blockchain

July 27, 2016
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When I first came across PoW, thoughts of the dynamic duo batman and robin came to mind. Then “Prisoner of War”. Maybe Proof of Weapons (of Mass Destruction)? It actually stands for Proof of Work and to understand it, let’s take a step back. Miners process transactions on the blockchain. What this really means is that miners collect all the transactions into a block and then validate and verify the information based on preset rules. Once all the rules are satisfied, miners then proposes that their particular collection of transactions should be accepted as the next block on the blockchain. Thousands of miners around the world do this, so whose block should be accepted? This is where Proof of Work comes in. All the miners need to “prove they did some work”. They don’t have to prove they did the most work or the best quality work, just that some work was done. Proof of Work is designed to be computationally hard to perform but easy to validate and also random in nature. There are lots of in-depth articles on the inner workings of PoW but let’s draw an analogy. Imagine having 2 dice. The chances of obtain a total of […]
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Digital signatures and the blockchain

July 14, 2016
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Introduction Understanding how digital signatures work is fundamental to understanding how blockchain technologies work. Let’s first draw a comparison to paying a restaurant bill with a credit card. Paying a bill at a restaurant Think of what happened the last time you paid your bill at the restaurant with your credit card. Here is a snapshot: You pull the card from your wallet and you might have a photo ID on the card. This proves you own* the card. You sign the bill in front of the waiter. The proves you are the “rightful” owner of the card. You check the receipt against the bill. You prove that the amount charged hasn’t been altered somewhere in the process. * It actually proves possession of the card but the entire process serves to illustrate a simplistic view and is not without it’s flaws. These 3 points illustrate 3 key properties: Ownership. The card belongs to you. Transaction authentication and non-repudiation. The waiter can verify that the owner signed the bill and the owner cannot deny the signing. Data Integrity. The amount charged was accurate. How can this be performed in a digital world where both parties hide behind a screen, do not know […]
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Bitcoin nodes around the world

July 12, 2016
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https://bitnodes.21.co is a very interesting site that shows all the bitcoin nodes around the world in real time. Bitcoin nodes are individuals and companies that support the bitcoin peer to peer network.
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