Selfish Mining: What It Is and Why It Matters

What Is Selfish Mining?

Bitcoin runs on incentives. To keep the network secure, miners are rewarded when they act honestly—processing transactions and adding new blocks to the blockchain. The system assumes that miners will follow the rules because it’s the most profitable option. But what if someone tries to “game” the system for more rewards?

That’s where selfish mining comes in. It’s a strategy that lets miners gain an edge by withholding newly mined blocks instead of publishing them immediately. By staying just a few steps ahead of the rest of the network, a selfish miner can trick others into wasting effort on a blockchain that ends up discarded—allowing the selfish miner to claim more rewards.

Let’s break it down.

How Selfish Mining Works, Simply Explained

Imagine four miners—Liam, Maya, Zoe, and Ryan—each control 25% of the Bitcoin network’s computing power. Liam, Maya, and Zoe follow the rules. Ryan doesn’t.

Whenever Liam, Maya, or Zoe find a block, they immediately broadcast it to the network. But if Ryan finds one, he keeps it secret. If luck is on his side and he finds a second block before anyone else, he now has a hidden chain that’s longer than the public one.

While the others are still trying to catch up, Ryan keeps mining in secret. Once his chain is only one block longer than the public chain, he reveals it. Bitcoin follows the longest chain rule, so the network switches to Ryan’s version. That means all the work done by Liam, Maya, and Zoe gets discarded—and Ryan collects all the block rewards.

By manipulating the timing of his block releases, Ryan wastes the resources of the other miners and earns more Bitcoin than his fair share.

Is Selfish Mining Dangerous for Bitcoin?

It’s not just an annoying trick—it could actually be a threat to Bitcoin’s core structure. In theory, other miners might decide to join a selfish mining pool if they think they’ll earn more that way. Over time, this could lead to one group gaining too much power.

That’s exactly what researchers Ittay Eyal and Emin Gün Sirer warned about back in 2013. Their paper, “Majority is not Enough,” explains how selfish mining could snowball into a centralized power grab. If one pool gets over 50% of the network’s mining power, it could launch a 51% attack —reversing transactions and breaking the trust that holds Bitcoin together.

Still, not everyone believes it’s a serious risk. Some argue that miners are incentivized to protect Bitcoin’s reputation. If the system becomes unstable, the value of Bitcoin could drop—hurting everyone’s bottom line.

Final Takeaway: A Game of Strategy and Trust

Selfish mining is more than a technical glitch—it’s a reminder that incentives drive behavior in crypto. If enough people believe that cheating pays off, it could slowly chip away at what makes Bitcoin powerful: its decentralized trust.

But selfish mining isn’t an easy path. It requires luck, timing, and coordination. And if it ever becomes widespread, the community might step in with technical fixes or social pushback.

For now, Bitcoin remains resilient. But as the game evolves, it’s crucial to watch how strategies like selfish mining challenge the balance between profit and principle.