Friday, July 31, 2015

WEP vs WPA/TKIP vs WPA2/CCMP

  • Layers



  • WEP MPDU
Figure 1: WEP MPDU 































  • WPA/TKIP MPDU
Figure 2: WPA MPDU




  • WPA2/CCMP MPDU
Figure 3: CCMP MPDU



ENCRYPTION FLOWS

  • WEP

Remarks:

  1. WEP 40(5 char)/104(13 char) uses 40/104 bits WEP Key respectively which is STATIC. 
  2. WEP is prone to IV collisions & weak WEP keys. 
  3. No Sequence number & MIC is available. Hence, prone to many other attacks.  
  4. Upto 4 keys can be defined on each end & different key can be used for encryption & decryption. 

  • TKIP


Advantages over WEP: 
  1. Uses Dynamic keys (temporal key PTK, GTK) which is generated after 4 Way handshake. PTK/GTK is 128 bits long.
  2. WEP Seed generation is made more advanced. 
  3. MIC introduced which provides data integrity. 
  4. TSC Introduced: Transmit Sequence number helps to prevent replay & re-injection attacks. 
  5. TKIP countermeasures defined in case of MIC failure. 


  • CCMP



Remarks:

  • MIC protects certain portion of MAC header along with data.

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