Title: A_new_standard_for_encoding_chain_ID___transaction
Category: EIPs

Author: microbecode
Date: 2025-04-23T10:58:42.655Z

I was thinking of a standard that encodes two things into one string:

An EVM chain id
A transaction hash

Such string could allow users to uniquely know on which network the transaction occurred. Currently it requires extra communication to inform the user which chain the transaction hash happened on.
Does something like this exist already?
There are some similar EIPs, such as:

For block explorer API routers: EIP-3091: Block Explorer API Routes
Using network names: ERC-3770: Chain-specific addresses

The first one above is not very relevant, but the second one is quite close to what I had in mind. The problems with the second one are, in my mind:

It doesn’t allow using testnets
Who decides what are the shortnames for each network

If instead of shortnames we utilize a commonly agreed-upon chain id (https://chainlist.org/) , both of the problems are solved.
The new encoding format might be something like “1:0x123” where “1” is the chain id and “0x123” is the transaction hash.
The real end goal would be to also create a website that guides to the right blockchain explorer based on this new string type. So users simply enter the string and they get redirected to the right blockchain explorer. But such website/service is a separate issue.
What do you think?

Author: SirSpudlington
Date: 2025-04-23T21:29:37.825Z

I like this idea it would help with UX across the several L2s (and forks), although, using chainlist.org may not be the best of ideas, as it is quite cluttered. I’d avocate for a separate consensus process, e.g. separate ERCs and an initial list.
It may also be a good idea to indicate to the user when a raw chain id is present e.g. id-1:0x123...ABC It may make it look more natural as EIP-155 chainIDs are not really designed for user facing environments.
Another issue, is that it may cause confusion with ERC-3770 at a first glance, especially with some dApps condensing the middle bytes of tx hashes and transactions to ....

Author: microbecode
Date: 2025-04-24T04:53:37.552Z

Thanks for the feedback!
I’m curious, in what way do you consider chainlist ‘cluttered’? Do you consider the list of IDs cluttered or just that website somehow?
I don’t see any problems with the list of IDs. They are, as far as I know, all unique. And, as far as I can tell, the numbers are not spammed to death (somebody for example reserving all numbers within u32). I don’t see a reason to duplicate this effort in a new ERC - I don’t see how the process could be made much better.
I think it’s a good idea to consider adding also some other data to the string. On the other hand, tx hashes are also really not designed for user facing environments - adding something more user un-friendly doesn’t make it much more horrible looking  But I don’t have a strong opinion in either direction currently.
Apps can continue truncating the middle of the tx hash. But you are correct that they may need to reconsider which parts to show and which not - but I’m unsure if this standard should consider that aspect at all.

Author: SirSpudlington
Date: 2025-04-24T10:39:13.791Z

It’s just that chainlist has thousands of entries, and they could change them at any time, adding or removing; it would just make it very hard to implement this standard.

Author: microbecode
Date: 2025-04-24T11:05:25.148Z

Well the source should be GitHub - ethereum-lists/chains: provides metadata for chains (as mentioned in EIP-155). In theory that can also change, but if those are changed the ecosystem will have a lot bigger problems than just directing links to the wrong block explorer.
And, as I said, it’d be hard to create any better, alternative system.

Author: SirSpudlington
Date: 2025-04-24T12:13:14.141Z

Ah, I missed that EIP-155 specifies a list, in that case, that would be absolutely be better, you are right.

Author: microbecode
Date: 2025-04-25T06:52:42.121Z

Currently, I’m especially looking for more feedback and ideas on the following topics:

What should be the string format? Here are some variants where “123” is the chain ID and “0x567” is the tx hash:

“123:0x567”. Pros: A typical formatting used for example in ERC-3770: Chain-specific addresses . Cons: parsers may confuse this new EIP format with that old format
“123-0x567”: Pros: Less likely to be confused with 3770.
“chainid-123-0x567”: Pros: harder to confuse with other formats, makes the use more explicit. Cons: Makes the string longer and parsing a bit less elegant. Also looks a bit confusing.
“0x567-123”: Cons: The chain ID is more important and should be first
“eip155:123:tx:0x567”: Pros: Makes this relevant also for non-EVM chains, as discussed here. Cons: longer string.
Something else, what?


Is “Meta EIP” the right category for this?
…And most importantly: does some standard already exist for this?

Author: SirSpudlington
Date: 2025-04-25T08:42:34.536Z

microbecode:

Is “Meta EIP” the right category for this?


I’d say this would be better as an ERC.

Author: microbecode
Date: 2025-04-26T07:19:10.594Z

Someone pointed me to CAIPs/CAIPs/caip-10.md at main · ChainAgnostic/CAIPs · GitHub . That specifies something similar, but for addresses, and not tied to EVM.
Now the problem becomes if the standard in this Magicians post wants to be compatible with CAIP-10, so this can be later expanded to be non-EVM specific, if wanted. How to distinguish whether the string refers to a transaction hash or to an address? Some ideas:

Use a different separator at some point (or in all of the separation points). For example “:” means it refers to an address and “-” means it refers to a tx hash.
Add a static string, like “tx” to some point of the string. Probably best at the end so it can be made later non-conflicting with CAIP-10. (Adding the “tx” to the beginning, like tx:123:0x567, would break the syntax of CAIP-10, but at the end it’d just expand CAIP-10)

I’m starting to lean towards syntax “123:0x567:tx”. It’s longer than just “123:0x567” but the longer syntax makes it somewhat compatible with existing standards. The only non-compatible part would be the “:tx” at the end.

Author: microbecode
Date: 2025-04-28T15:04:11.683Z

Fair point!
I mentioned chainlist as an example. Sorry, I should’ve been more explicit: the chain ID should use the IDs listed here (and in the repo linked to in the EIP): EIP-155: Simple replay attack protection
That can get hacked. But the standard I’m proposing doesn’t “care” too much about that. If someone is interacting with chainId 115511 (Sepolia), I doubt they change the number because some EIP/repo gets hacked. The only thing that’d suffer are some direct integrations that utilize that chain ID list directly - no idea which and where. But for this standard, that’s not a big concern.
The worst case scenario, from this standard’s point of view, is that some integration starts handing wrong chain IDs that are used by this standard. But there’s nothing this standard can do about it - there is no verification for the used IDs.
I agree wallets should be checking these things. I have no idea if they do.

Author: microbecode
Date: 2025-04-28T16:07:03.548Z

This standard doesn’t force anyone to remember anything. This just defines the encoding of chain ID and transaction hash put together. It’s up to other parties (wallets, exchanges, explorers, protocols, …) to actually take this into use - I don’t think anyone wants to be forming these strings manually.
And yes, the repo getting hacked is a concern, but not something we should try addressing here. I encourage you to start a new post about it, discussing the options. Let’s try to stick to the topic here.

Author: SirSpudlington
Date: 2025-04-28T20:12:55.140Z

Worst case scenario is that the source repository gets hacked, the result of this is that you’d see a different name in the start of the tx hash, but with the way tx signing works, the odds of having the exact same transaction hash on two different networks are basically zero (even if the transaction is functionall the same due to encoding changes). So the only attack vector here is mildly inconveniencing a user, if they copy the transaction hash. Best case, they just click a link to the block explorer and nothing happens.

Author: u59149403
Date: 2025-05-07T12:49:42.678Z

Draft PR already exists: new CAIP - Transaction Object Addressing by bumblefudge · Pull Request #221 · ChainAgnostic/CAIPs · GitHub , I think we should iterate on it