We just finished building Gibbername, a simple on-chain naming system. We built a library and simple command-line tool that lets you register, transfer, and look up "gibbernames" like goltor-rulnuq-keh from any Rust program.
Most importantly, this whole process is entirely trustless! A malicious RPC network or full node is unable to lie to a Gibbername client at all.
Hopefully, you also got a taste of how different Mel's off-chain composability is from the current Web3 paradigm. Instead of writing a smart contract with an on-chain API that other on-chain code calls, you designed an on-chain data structure that off-chain code maintains and looks up. This then enables you to write apps that integrate Gibbername's decentralized security without writing a single line of on-chain smart contract code (something that you can't really do with ENS and the like!)
Gibbername, as it is, is close to the simplest possible useful protocol we can build on Mel. An actual, production naming system that could compete with DNS and the like would need a few more features. Here we sketch how they can be implemented:
Off-chain data storage
Right now, the entire binding is stored on the Mel blockchain. This is not all that efficient, since blockchain space is pretty expensive. Furthermore, it can be slow to follow the very long Catena chains that would result from a name that has been rebound many different times.
We can move more data off-chain to solve both problems:
On-chain, we bind to the hash of the binding rather than the binding itself.
Off-chain, we use an insecure decentralized key-value mapping, like a DHT, to map each gibbername to a proof of on-chain binding, consisting of three items:
The initial on-chain transaction, as well as a Merkle proof of inclusion that the blockchain location represented by the gibbername truly maps to this transaction
The last on-chain transaction in the Catena chain, along with a proof that the Denom::Custom(...) output is unspent.
We do not need any transactions in between, since there could not possibly be another unspent output with the same Denom, since there's only 1 in total produced by the first transaction.
The contents of the binding itself, which must hash to the on-chain binding in the output of the last on-chain transaction.
In such a system, lookups can entirely be done off-chain and massively scale. Bindings can also be arbitrarily large without burdening the blockchain.
Instead of using blockchain locations as the name, we can use an on-chain data structure to keep track of human-readable names. This data structure will be a certain "shape" in the coin graph, just like a Catena chain, but encoding a key-value graph instead (e.g. Bitforest). Upholding this invariant would require writing a Melodeon covenant.
Better registration UX
Once we have mature GUI wallets with "wallet URI" support, as well as immutable frontend hosting, we will be able to write a simple webpage where people can manage their gibbername names.