NAME_1 believes he has come up with a simple way of performing authentication. His system, PompousPassTM, uses RSA signatures. Let Idx and Pwx respectively be the username and password for user x, and (x+, x−) be the public/private keypair associated with user x. Assume that the server S knows the user’s username (Idx), password (Pwx), and his public key (x+). To authenticate to the server, x sends:
x → S : Idx, r, Ex−(Idx|Pwx|r)
where r is a nonce.
The server decrypts the message using x’s public key, and authentication proceeds if and only if (1) the transmitted password matches the password stored in the server’s database and (2) the nonce is fresh.

 Is this system secure? Why or why not? (Explain with examples. Max 2 paragraphs).