So, in proof of stake mechanism a node is chosen (based on the staked eth) to propose a valid block. The node just select the beneficial transactions out of the transaction pool and then bundle transactions together, execute them and find a valid hash.

But what if they tamper with some of the transactions or add a fake transaction into the bundle and then generate a valid hash for the tampered bundle and broadcast this block to the network. Does the other nodes will just add this block to their chains or verify the transactions before adding to their database? If the later how does they verify these transactions whether it is fake or a tampered transaction?

P.S.: I am a newbie and this doubt has been bugging me for quite a time .

1 Answer 1


If a block is invalid (contains invalid transactions, wrong state transition, etc.), then other nodes wont even accept it. Nodes run all the blocks they receive, and if a proposer proposed a false block, no other nodes would accept it. The block wouldn't even be valid for other validators to attest.

  • What does it meant by "run the block"? Does this mean that the nodes validates the signature in the transactions? What does exactly happen when they run the block? Coz how would they know whether the transactions are fake or invalid? Oct 17, 2022 at 19:37
  • @TusharBharti When a new block is created, it's sent to the network. Nodes on the network gossip it around until everyone has it. When a node downloads it, it will do all necessary validations to confirm it is valid - correct builder, header, transaction signatures, etc. - this includes running all of the transactions in the block against their local state and validating that none were done incorrectly. This is just part of syncing
    – natewelch_
    Oct 17, 2022 at 19:56

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