The Median EB “Attack” Against BU Explained

Is this an “Attack”?

The effect of this “attack” is that a rogue large block enters the network. First, let’s assume that the Bitcoin network is in a steady state with 2MB blocks being mined (this is the worst case). As stated in the scenario, the malicious miner mines a 3MB, a 6MB and a 32MB block. So that is 1, 4, and 30 MB of transactions over the steady state, for a total of 35MB of transactions.

The Effect on Miners and Full Nodes

Because all other miners are still mining at 2MB, on average this attacker has committed extra 35MB of transactions within a period of 100 2MB blocks (the attacker must mine 3 blocks and has 3% of the hash).

The User Experience

Let’s look at the user experience. The users are what is important here to ensure that Bitcoin remains the most useful cryptocurrency.

The Economic Factor

I’m not going to work through all the math here (maybe people can contribute). But I do want to mention costs.

The Human Factor

Many individuals have already observed that this attack assumes an active human attacker but passive humans in the rest of the Bitcoin network. But the truth is that Bitcoin has grown to where it is a human-computer network. Due to the 2013 hard fork, Bitcoin would not be what it is today if it wasn’t for timely intervention of humans if and when things go wrong. And an “attack” definitely qualifies as things going wrong. Is it fair to assume that all 45% of the original hash power signaling for 2MB is ignoring their 4 orphaned blocks?


This “attack” will not affect the technical operation of the Bitcoin network, except perhaps to enhance the end user experience due to faster confirmation times.



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