Oh they absolutely could. They could run their own relay and indexing service and control all content which goes in and out. It wouldn't be a vanilla experience, but it's how they would probably integrate Nostr. 

 But if an X user’s note ends up stored on a relay that doesn’t support delete, it’s stuck out there in the wild. 

 That's something they'll have to come to terms with and give users a choice to opt-in. I assume it will a check box. "Participate in Nostr: your Tweets will be sent to Nostr. Please note that doing so, your Tweets on Nostr may not be able to be deleted from all Nostr servers." 

 I don’t see it happening under the current regime. 

 ?* 

 They would need the secret key that only the bridge has, but yes. If someone broke into the server they could impersonate ActivityPub users. That's no different from any site though. Except that Nostr would make it hard or impossible to recover from a breach like that since compromising a key is permanent. 

 🤔 

 ok in reverse. if i have a my nsec on nostr and the bridge emulates an account on mastodon, my nsec on nostr side is always secure right? 

 technically the likelihood of a mastodon person to talk / interact / get data from a nostr person is lesser than than the other way round so as long as my nsec is secure i am fine. i practice safe nsec. hehe 

 Your nsec wouldn’t be compromised. The only risk is to the corresponding ActivityPub ID on the other end. 

 i wonder if we could run a personalized version of mostr bridge? but then i guess, that is what ditto is all about anyway 

 What attack vectors are there where this could happen and how secure is the mostr.pub server? The fact that it’s centralized like this is fairly concerning, ngl. 

 i think all of this concern are probably the reason why alex comes out with ditto, right? 

 yes, if you guess the secret, which may be a different salt for each user for more fun