The apps don't need to host HAS infrastructure. They only need to support HAS protocol and be able to "talk" with a HAS server.
An app built on Telos could perfectly let users sign in with their Hive account. If the Telos devs want to collaborate with us, they are more than welcome. It would be an excellent use case to demonstrate how useful the HAS project can be.
It can work cross-chain because the HAS infrastructure is "transactions agnostic". So we can easily imagine a Telos App talking with a Telos Wallet but authenticating and securing the connection with the help of a Hive account.
I have already informed our core devs about this. Thank you.
Sir, I maybe a newbie, but I find this proposal exciting. I can imagine this will be a hit and the Hive blockchain will surely benefit from this system. I have voted for your witness just now. Hope this will materialize.
Thank you for your support @deixykerr, really appreciate it! 👍