Thank you very much. 

 With a dummy account, I have been exploring Spring, the Nostr browser, for more than a couple of month. It's much more than awesome. Almost the whole of Nostr comes under the purview of a single app. Just wanna be sure it's surely secure to entrust worth my private key. Should I feel assured, @Vitor Pamplona? 

Also @brugeman, would you please explain?  

 Spring is safe, your keys are stored on disk in encrypted form, apps cannot access them, the source code is open.  

 Thank you very much, @brugeman, for taking your precious time to reply. What you tell is assuring. How does it encrypt nsec on disk please? Encrypt with what?

 

 With keys generated inside the Android's internal keystore.   Android ensures only Spring can access those keys, decryption is performed inside the keystore.  

 That sounds great. Thank you.