How trustless and secure are Events? They are part of the consensus as they are generated out of a smart contract code. so in theory they are trustless and secure. But they are not stored on chain or in the state trie, and you would have to sync it again to find the event.

In my mind they are as secure as state, do you confirm?

New evidence: transaction receipt have their own merkle trie in a block https://ethereum.stackexchange.com/a/757/264 Means logs can be found in the recipe tree and is as verifiable as state.


1 Answer 1


I am also working on this, and I agree with you. Per definition, as long as the transaction hash is recorded and stored in the block, it should be considered as secure.

On the other hand, as my collegue stated, what happens if the event logs are no longer handled by the nodes? This rises a new problem.

Also: The reason for our investigation in this topic, was the cost of saving directly through smart contracts (where 1 byte of saving costs 20k gas compared to 1 byte of log which costs 8 gas, on 1kb this is a difference of 20M vs 8K gas, with current prices of Ether, this is highly relevant)

  • 3
    maybe you could make this as a comment as you don't really bring the proof that it's secure but only agree with Roland. Commented Jul 10, 2017 at 13:54
  • If you're unable to comment because of not having enough rep, please star the question and check back for answers at a later time. Commented Jul 10, 2017 at 18:01
  • Thanks for the tips guys. This was my first answer/post on stackexchange, so pardon my retardedness. Will follow this convention ahead!
    – Robinron
    Commented Jul 12, 2017 at 11:19

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