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How Monero’s proof of work works

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Why This Matters

Monero's RandomX proof of work is designed to promote decentralization by making mining more accessible to regular CPUs, unlike Bitcoin's ASIC-optimized system. This approach aims to prevent centralization of mining power and hardware manufacturing, ensuring a more distributed network. Understanding RandomX highlights ongoing efforts in the crypto industry to balance security, decentralization, and resistance to specialized hardware.

Key Takeaways

Monero’s proof of work is called RandomX.

Monero does not ask miners to run the same tiny hash function over and over. It asks them to run a small random program on a virtual machine, hit memory hard while doing it, and then hash the result.

Bitcoin’s proof of work is great for specialized chips because the work never changes. RandomX was built to do the opposite. It tries to make efficient mining look as much like a normal CPU workload as possible.

Short version

Here is the shortest useful summary:

Monero takes the candidate block header plus a nonce. It also uses an older block hash as a medium-term key. That key builds a large shared memory dataset. The candidate block input is hashed to create a seed for a special virtual machine. The VM runs integer math, floating-point math, branches, and lots of memory accesses across 8 chained programs. The final machine state is hashed into a 256-bit output. If that output is below the network target, the block is valid.

The interesting part is not the yes-or-no rule at the end. Every proof-of-work system has that. The interesting part is how Monero makes each hash attempt expensive in the exact ways normal CPUs are good at and custom chips hate.

Why Monero does not use a simple hash

If your proof of work is just “run this fixed function on new inputs until you get a lucky output,” hardware designers have a clear job: build silicon that runs that exact function as cheaply and as fast as possible.

That is what happened to Bitcoin with SHA-256 ASICs.

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