Great question!

Short answer, No.

Your nostr keys are used to encrypt the questions you have made and the answers you have received and backed them up on nostr directly from your device. You never reveal your nostr identity or any other personal infomation while using cypherflow.

So cypherflow never knows who is using it, and all of the user chats are just encrypted gibirish in nostr relays. Only the corresponging knows about then and only them can see them.