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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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