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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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Visiting Coinbase in San Francisco

August 16, 2016
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    I had the privilege visiting the Coinbase Headquarters in San Francisco as I was interested in a position there. Coinbase is one of the largest digital currency exchanges in the world and certainly well funded. I had an initial phone screening conversation with Brittany, the HR person there. Then I talked to another HR person, Alvin. I then had a phone interview with John. I was then invited to come onsite for 2 face to face technical interviews. Gotta say, the process was thorough! Their office was nice with amazing views in downtown San Francisco. The first technical interview was with Brad who was a nice and knowledgable guy. I was given a problem of trying to balance the spend of a group of people where one person paid for the rest of the group or sub group. After an hour I then moved to another room and talked with Craig, a software engineer where I had a warm up question. It was to find the angle between the long hand and the short hand of an analogue clock at the time of 3:15. Next, I had to code up a function to perform the Fibonacci sequence using https://codepair.hackerrank.com It […]
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Nakamoto: San Francisco’s First Bitcoin Store

August 11, 2016
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My curiosity for knowledge led me to visit a store in San Francisco called Nakamotos. It wasn’t hard to find but I walked right past it the first time. I was expecting but the actual shop front was like:       It was pretty quite on the day I was there. Inside were 2 ATMs, some books and lots of other souvenirs. Managed to leave with a souvenir for myself. I walked from San Francisco CalTrain station partly to explore the city. It took ages. I would highly recommend Ubering it.  
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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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Ethereum update their crowdsale tutorial page

July 21, 2016
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I was surprised at why the sample code was set as regular text. Seems likes the guys at Ethereum may have missed an opening bracket or something. It was good though to see Ethereum update their crowdsale tutorial page at https://www.ethereum.org/crowdsale. I’m sure others would have noticed this as well!
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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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Transaction fee for mobile bitcoin wallets

July 9, 2016
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Transaction fees of mobile bitcoin wallets can vary with some set by the user and some set and controlled by the wallet provider.
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Who’s Securing the Blockchain?

June 30, 2016
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Back in the days when blockchain mining started, anyone could mine with their regular home computer. Unfortunately this was as decentralised as it got. Mining remember, is the process of confirming transactions and creating a block on the blockchain. It is a fundamental component of the blockchain technology. No mining, no blockchain. As the story goes, mining technology has evolved at an incredible speeds. From using home computers, known as CPU mining, to using dedicated gaming graphics card,  (GPU mining), to using programming chips (FPGA’s) and now Application Specific Integrated Chips, ASIC’s. ASIC’s have evolved from 55 nanometer silicon wafers to 28 nm and now, to the release of 14nm chips. The lower the number, the more chips on the silicon, the more processing power to be had. To understand who is mining to secure the blockchain, let’s go to the top of the food chain. The chip foundries. These are the guys that actually make the chips and there are only a handful of foundries around the world such as Global Foundries (GF), Taiwan Semiconductor Manufacturing Company (TSMC) and Semiconductor Manufacturing International Corporation (SMIC). An enormous amount of investment is required to fabricate mining chips To get in the […]
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How to send ethers in Mist

June 27, 2016
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With your Mist wallet installed and synchronised to the test network, let’s send some test ether to a friend. This should take less than 5 minutes.
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Let’s experience the blockchain using Ethereum

June 24, 2016
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Everybody uses the Internet to exchange information but with the blockchain we can exchange and transact value and make contracts about how this is done. Ethereum is a public blockchain that provides a decentralized virtual machine that can execute peer-to-peer contracts using a cryptocurrency called ether. Time to experience Ethereum for yourself in a safe test environment. The first step is to download Mist. Mist is a “wallet/browser” used to store ether and interact with Ethereum contracts.  It is easy to use and you don’t have to be a developer or write any code. It will take about 5 minutes to set up the wallet but about 1 hour to sync to the network and about another hour to successfully mine some test ethers. Step 1: Download Mist Go to https://github.com/ethereum/mist/releases and find the latest version to download for your system. You will see a number of options for downloading. Choose the one which is right for your device. For example, if you are using the Windows platform and have a 64 bit machine you will choose Etherium-Wallet-win64-0-7-5.zip Step 2: Installation At this point you will be shown a screen that asks you whether you want to connect to the ‘real’, main […]
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Ethereum – creator of smart contracts in a decentralized network

June 21, 2016
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Ethereum is a platform that allows the creation of smart contracts. To understand how Ethereum works, it is important to appreciate the underlying concepts upon which it was built, that is Bitcoin and the blockchain. When the first bitcoin transaction took place on the 3rd of January 2008, (known as the genesis block), it introduced to the world the concept of ‘decentralized consensus’. This is where everyone on the bitcoin network agrees that something has changed ownership, forming a ’crypto-currency ledger’. The “bitcoin” blockchain is simply a collection of all transactions since bitcoins started, mathematically linked together to form a chain. The blockchain also encapsulates some key concepts: Public Key Cryptography (the ability to verify and authenticate a message from a sender using a set of public and private keys that are mathematically linked. Cryptographic Hash Functions (a function which takes an arbitrary length input or ‘message’ and returns a fixed-size alphanumeric string, which is called the hash value – sometimes called a message digest, a digital fingerprint, a digest or a checksum) Peer to Peer Networking (computing or networking through a distributed application architecture that partitions tasks or work loads between peers. Peers are equally privileged participants in the […]
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Deep Web: Alex Winter

May 6, 2016
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This documentary touches on a lot of fundamental principles around the right to privacy and anonymity. It brings to life and joins some of the dots that Digital Gold talked about. Definitely worth a watch. Deep web at IMDB  
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Protected: STEM

May 4, 2016
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There is no excerpt because this is a protected post.
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Protected: Innovation Challenge

January 7, 2016
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There is no excerpt because this is a protected post.
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