[Karellen]

From the article:

> miners and nodes need to spend a very long time processing some blocks. This is due to the EXTCODESIZE opcode, which has a fairly low gasprice but which requires nodes to read state information from disk;

AIUI, the data in the blockchain isn't just "data". It's actually small bits of code that execute inside a VM, which each node needs to execute in order to "understand" the blockchain. "EXTCODESIZE" would be one of the instructions in this particular VM.

I think that most blockchains either have a complexity limit per record/transaction, or have a complexity "cost", so that complex code is more costly to insert into the blockchain.

However, in this case, it sounds like someone has figured out how to insert some code that is actually more complex than the complexity-measuring code thinks it is, and is therefore causing all miners (all users?) to perform higher-than-expected amounts of computation to parse the blockchain, to the point where they can't keep up with the network.

(Corrections welcome)

[RexetBlell]

The transactions are verified by all full nodes (which are basically all users).

[themoon]

This is exactly correct.