inse 6110 found vulnerabilities during original design review

the sensitive db had plain private and symetric keys of everyone meaning the only security it was doing was in case one of the server gets hacked no message could be read unless the other one also fall

also in the first design the server was the one decrypting the messages meaning that the encryption was not end to end and thus the only actual encryption was HTTPS meaning that all the keys were just for show

Since the user's hashed password is store in the same DB as all the encrypted keys if the database fall any user could simple bruteforce the hash and then have access to all the keys 
if we separate the 2 any attacker would have to bruteforce the keys by first hashing random strings and then trying to decrypt the keys using this temporary hash making it much harder to crack
