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31.
CCMP/AES encryption adds an extra _________ of overhead to the body of an 802.11 data
frame.
- A.16 bytes
- B.12 bytes
- C.20 bytes
- D.10 bytes
- E.None of the above
- Answer & Explanation
- Report
Answer : [A]
Explanation :
Explanation :
| CCMP/AES encryption will add an extra 16 bytes of overhead to the body of an 802.11 data frame. Eight bytes are added by the CCMP header and 8 bytes are added by the MIC. WEP encryption will add an extra 8 bytes of overhead to the body of an 802.11 data frame. When TKIP is implemented, because of the extra overhead from the extended IV and the MIC, a total of 20 bytes of overhead is added to the body of an 802.11 data frame. |
32.
TKIP/ARC4 encryption adds an extra _________ of overhead to the body of an 802.11 MPDU.
- A.16 bytes
- B.12 bytes
- C.20 bytes
- D.10 bytes
- E.None of the above
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| When TKIP is implemented, because of the extra overhead from the extended IV and the MIC, a total of 20 bytes of overhead is added to the body of an 802.11 MPDU. CCMP/AES encryption will add an extra 16 bytes of overhead to the body of an 802.11 MPDU. WEP encryption will add an extra 8 bytes of overhead to the body of an 802.11 MPDU. |
33.
An HT client STA is transmitting to an HT AP using modulation and coding scheme (MCS)
#12 that defines 16‐QAM modulation, two spatial streams, a 40‐MHz bonded channel,
and an 800 ns guard interval to achieve a data rate of 162 Mbps. According to the IEEE,
which types of encryption should be used by the HT client STA? (Choose all that apply.)
- A.Static WEP
- B.Dynamic WEP
- C.TKIP/ARC4
- D.CCMP/AES
- E.All of the above
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| The IEEE 802.11n amendment states that an HT station should not use WEP or TKIP when communicating with other STAs that support stronger ciphers. HT STAs should not use pre-RSNA security methods to protect unicast frames if the RA or address 1 of the frame corresponds to an HT STA. On September 1, 2009, the Wi-Fi Alliance also began requiring that all HT radios (802.11n) not use TKIP when using HT data rates. TKIP is also not supported for VHT radios (802.11ac) when using VHT data rates. |
34.
CCMP/AES uses a ________ temporal key and encrypts data in ______ blocks.
- A.128‐bit, 128‐bit
- B.128‐bit, 192‐bit
- C.192‐bit, 192‐bit
- D.192‐bit, 256‐bit
- E.256‐bit, 256‐bit
- Answer & Explanation
- Report
Answer : [A]
Explanation :
Explanation :
| The AES algorithm is defined in FIPS PUB 197-2001. All AES processing used within CCMP uses AES with a 128-bit key and a 128-bit block size. |
35.
When using an encryption suite that implements an asymmetric algorithm, which of the following
statements is true? (Choose all that apply.)
- A.Both the encrypting and decrypting parties share the same key.
- B.Asymmetric algorithms generally are faster than symmetric algorithms.
- C.Asymmetric algorithms generally are slower than symmetric algorithms.
- D.Public and private encryption keys must be generated.
- Answer & Explanation
- Report
Answer : [C, D]
Explanation :
Explanation :
| Asymmetric algorithms use a pair of keys—a private key that is used for decryption and a public key that is used for encryption. Asymmetric algorithms generally require more computer processing power than symmetric algorithms. |
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