单项选择题
A. Blocking cipher andnon-blocking cipher
B. CBC cipher and EBC cipher
C. Block cipher and Stream cipher
D. Blocker cipher and Streamer cipher
E. 3DES cipher and AES cipher
单项选择题 WhichSSLprotocoltakesanapplicationmessagetobetransmitted，fragmentsthedataintomanageableblocks，optionallycompressesthedata，appliesaMAC，encrypts，addsaheader，andtransmitstheresultingunitinaTCPsegment？（）
单项选择题 ForaroutertoobtainacertificatefromaCA，whatisthefirststepofthecertificateenrollmentprocess？（）
多项选择题 Whichtwostatementsarecorrectabouttheaaaauthenticationlogindefaultgrouptacacs+localglobalconfiguration command？（）