单项选择题
Why is NTP an important component when implementing IPSec VPN in a PKI environment？（）
A. To ensure the router has the correct time when generating its private/public key pairs.
B. To ensure the router has the correct time when checking certificate validity from the remote peers
C. To ensure the router time is sync with the remote peers for encryption keys generation
D. To ensure the router time is sync with the remote peers during theDH exchange
E. To ensure the router time is sync with the remote peers when generating the cookies during IKE phase 1
相关考题
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单项选择题
UsingFTPpassivemode，aftertheclientopensthecommandchannel（port21）totheFTPserverandrequestspassivemode，whatwillbethenextstep？（）
A. The FTP server sends back an acknowledgment （ACK） to the client
B. The FTP server allocates a port touse for the data channel and transmit that port number to the client
C. The FTP server opens the data channel to the client using the port number indicated by the client
D. The FTP client opens the data channel to the FTP server on Port 20
E. The FTP client opens the datachannel to the FTP server on Port 21 -
多项选择题
Whichofthefollowingstatementsaretrue？（）
A. RC4 is a stream cipher
B. Stream ciphers require padding
C. AES is a block cipher
D. DES and 3DES are stream ciphers
E. AES is a stream cipher
F. AES， DES， and 3DES can be used as HMAC algorithms -
多项选择题
Whichofthefollowingstatementsaretrueregardinghashing？（）
A. MD5 produces a 160-bit result.
B. SHA-256 is an extension to SHA-1 with a longer output.
C. MD5 takes more CPU cycles to compute than SHA-1.
D. Changing1 bit of the input to SHA-1 changes 1 bit of the output.
E. SHA-1 is stronger than MD5 because it can be used with a key to prevent modification.
