A new private key for nostr is generated when you install eNuts. When you send Ecash via nostr using the wallet, the recipient has to check his dms in the client he is using (it should be a new dm request from an unkown pubkey).
Currently, the wallet can only receive Ecash that is sent to the new generated pubkey and can not read your actual dms because we dont have your private key. This is confusing and a better solution has to be implemented.
