问题：

[多选] Which two wireless security statements are true？（）

A . A TACACS+ server is required to implement 802.1x.
B . MIC protects against man-in-the-middle and replay attacks.
C . The 802.1x standard provides encryption services for wireless clients.
D . The AES （symmetric block cipher） is specified in the IEEE 802.11i specification.
E . The IEEE 802.11i specification uses RC4 as its encryption mechanism.
F . WPA requires TKIP and AES as encryption methods.