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BlockChain C# Implementation, BlockChain by using c# What is proof-of-work? Proof-of-work is a mechanism that existed before the first blockchain was created. It's a simple technique that prevents abuse by requiring a certain amount of computing work. That amount of work is key to prevent spam and tampering. Spamming is no longer worth it if it requires a lot of computing power. Bitcoin implements proof-of-work by requiring that the hash of a block starts with a specific number of zero's. This is also called the difficulty. But hang on a minute! How can the hash of a block change? In case of Bitcoin a block contains details about a financial transaction. We sure don't want to mess with that data just to get a correct hash! To fix this problem, blockchains add a nonce value. This is a number that gets incremented until a good hash is found. And because you cannot predict the output of a hash function, you simply have to try a lot of combinations before you get a hash that satisfies the difficulty. Looking for a valid hash (to create a new block) is also called "mining" in the cryptoworld. In case of Bitcoin, the proof-of-work mechanism ensures that only 1 block can be added every 10 minutes. You can imagine spammers having a hard time to fool the network if they need so much compute power just to create a new block, let alone tamper with the entire chain. Implementing proof-of-work So how do you implement it? Let's start by modifying our block class and adding the nonce variable in it's constructor. I'll initialize it's value and set it 0.