单项选择题
A.They use the same key for encryption and decryption of data.
B.They use different keys for decryption but the same key for encryption of data.
C.They use different keys for encryption and decryption of data.
D.They use the same key for decryption but different keys for encryption of data.
单项选择题 Forthefollowingitems，whichonecanbeusedtoauthenticatetheIPsecpeersduringIKEPhase1？（）
单项选择题 Which description is correct based on the exhibit and partial configuration？（）
单项选择题 Inabrute-forceattack，whatpercentageofthekeyspacemustanattackergenerallysearchthroughuntilheorshefindsthekeythatdecryptsthedata？（）