Supporting multiple chains with CAIP-122 about caips HOT 2 OPEN

This means that if you would like to authenticate yourself with SWIx for multiple chains then you need to sign multiple messages

Why is this the case?

• If you have an EOA there isn't a meaningful difference between a signature for different chainIds. You can just treat 1 as any, or simply ignore the chainId
• If you have a smart contract account and use eip1271 you need to have a unique signature for each chain regardless

**Can you provide an example of the problem you are trying to solve here? **
"I want to sign in with multiple chainids at once" is not a problem, it's a proposed solution.

If I were to take a guess on what problem you are trying to solve I think you need to give dapps access to call rpc methods for multiple chains? However, I'm not sure why SIWE is relevant for that?

from caips.

"Just ignore" is always a dicey way of specifying behavior; perhaps the best solution is an extension spec that specifies exactly how to ignore or override CAIP122 behavior if X and Y conditions are met (presumably, resource array members, since that's basically the only open-ended part of the spec)? Even if that extension CAIP is only applicable to eip155, it might still be worth writing in a generic way and profiling in eip155/caipXXX.md in case some almost-evm compatible L1 wants to use it the same way with slightly different recaps or recap-equivalent capability expression format...

from caips.