Fichas
Network Security in 802.11
Fichas del conjunto (13)
- 1Define confidentialityOnly TX and RX understand contents of msg
- 2Define AutheticationTX and RX to confirm each other's identity
- 3Define msg IntegrityContect of msg is not altered without detection
- 4Define Access and AvailabilityService accessible and available to users
- 5Two types of symmetric ciphers1) Stream cipher
2) Block cipher - 6How does stream cipher work?It encrypts 1bit/time
- 7How does block cipher work?Breaks msg -> same size blocks
Encrypt each block as 1 unit - 8WEP Encryption protocol1) Sender calcs ICV over data
2) Sender creates 24-bit IV, appends to 40-bit shared key
3) Sender appends keyID (8-bit)
4) 64-bit ->> generator ->> keystream
5) data in frame + ICV encrypted w/ RC4 - 9WEP Decryption protocol1) RX extract IV
2) Puts IV and shared secret key ->> generator ->> keystream
3) m(i) = ks (is) XOR c(i) (ciphertext)
4) Verifies integrity w/ ICV - 10What is nonce?Number used only once
- 11How is nonce used for authentication?To prove A is live, B sends A nonce, R.
A must return R, encrypted w/ secret key. - 12Security hole in WEP EncryptionIV will eventually be reused.
- 13Example of security holeX cause A to encrypt known plaintext, m(i).
X sees ciphertext,
c(i) = m(i) XOR k (i)
X knows c(i) and m(i) ->> find k(i)
Información
- Descripción
- Fichas sobre Network Security in 802.11, creado por Jo-Anne Tan el 08/11/2014.
- Creado por
- Jo-Anne Tan
- Visitas
- 9
- Valoración