Which two statements best describe the wireless security standard that is defined by WPA? (Choose two.)

A.
it specifies the use of dynamic encryption keys that change each time a client establishes a connection.

B.
It specifies use of a static encryption key that must be changed frequently to enhance security.

C.
It includes authentication by PSK.

D.
It requires that all access points and wireless devices use the same encryption key.

E.
It requires use of an open authentication method.

Explanation:
WPA is a more powerful security technology for Wi-Fi networks than WEP. It provides strong data protection by using encryption as well as strong access controls and user authentication. WPA utilizes 128-bit encryption keys and dynamic session keys to ensure your wireless network’s privacy and enterprise security .There are two basic forms of WPA:
WPA Enterprise (requires a Radius server)* WPA Personal (also known as WPA-PSK)Either can use TKIP or AES for encryption. Not all WPA hardware supports AES.WPA- PSK is basically an authentication mechanism in which users provide some form of credentials to verify that they should be allowed access to a network. This requires a single password entered into each WLAN node (Access Points, Wireless Routers, client adapters, bridges). As long as the passwords match, a client will be granted access to a WLAN.Encryption mechanisms used for WPA and WPA-PSK are the same. The only difference between the two is in WPA-PSK, authentication is reduced to a simple common password, instead of user-specific credentials.The Pre-Shared Key (PSK) mode of WPA is considered vulnerable to the same risks as any other shared password system – dictionary attacks for example. Another issue may be key management difficulties such as removing a user once access has been granted where the key is shared among multiple users, not likely in a home environment.

Reference: http://www.dslrepoits.eom/faq/wifisecurity/2.2_WPA

WPA is a standard-based interoperable solution designed to enhance the security of WLAN, which greatly improves the present and future level of data protection and access control of WLAN. WPA is evolved from the being developed IEEE802.11i standards and keeps compatible with its former. WPA can protect WLAN users data with proper deployment, and only the authorized network users can access the WLAN network.
WPA provides users with a temporary solution. The encryption of this standard adopts TKIP (Temporary Key Integrity Protocol). There are two authentication modes to choose :one mode uses 802.1 x protocol to authenticate, the other is known as PSK (Pre-Shared Key) Mode.