Double signing documentation is confusing

[peterzhangbo]

What is the meaning of Double Signing exactly?
Double signing: If someone reports on chain A that a validator signed two blocks at the same height on chain A and chain B, this validator will get slashed on chain A

And why be punished with it?

[rigelrozanski]

Interesting, assuming you got that from here https://github.com/cosmos/cosmos/blob/master/VALIDATORS_FAQ.md

I think this is confusing and needs to be reworded/made more explicit. Within the current definition, I think chain A and chain B are referring to two different "sections" so-to-speak of the same blockchain. In a poorly connected node network, there may only be a small number of nodes which connect two different groups of nodes which compose the entire validator set - in this case, if this "small number of nodes" were to suddenly go offline, the network would be considered partitioned. Likewise, malicious groups of nodes may try to use their position within a network to broadcast different transactions to different sides of the blockchain for nefarious reasons.

double signing is not in reference to signing two different chains - that would be acceptable behaviour as the chains are distinct (but possible sharing a validator set, these are complex but potentially allowable arrangements). Within the cosmos double signing typically refers two signing and broadcasting two different pieces of information (for instance a proposed block) for the same height for the same chain.

Hope this helps. Going to rename this issue to bring clarity to this point in the docs

[peterzhangbo]

@rigelrozanski U got me,thank you.

look forward to getting more information in updating docs.

[rigelrozanski]

yeah many of the docs are not in cosmos-sdk aka https://github.com/cosmos/cosmos-sdk/tree/develop/docs
aka https://cosmos.network/docs/ not this repo even, not sure what's going to become of this repo yet

[hsohaib]

This is to prevent the "nothing-At-stake" scenario, essentialy forcing the validator to choose one chain to prolong