Paper 2013/748

Plaintext Recovery Attacks Against WPA/TKIP

Kenneth G. Paterson, Bertram Poettering, and Jacob C. N. Schuldt


We conduct an analysis of the RC4 algorithm as it is used in the IEEE WPA/TKIP wireless standard. In that standard, RC4 keys are computed on a per-frame basis, with specific key bytes being set to known values that depend on 2 bytes of the WPA frame counter (called the TSC). We observe very large, TSC-dependent biases in the RC4 keystream when the algorithm is keyed according to the WPA specification. These biases permit us to mount an effective statistical, plaintext-recovering attack in the situation where the same plaintext is encrypted in many different frames (the so-called ``broadcast attack'' setting). We assess the practical impact of these attacks on WPA/TKIP.

Available format(s)
Secret-key cryptography
Publication info
Preprint. MINOR revision.
Contact author(s)
kenny paterson @ rhul ac uk
2014-03-01: revised
2013-11-17: received
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Creative Commons Attribution


      author = {Kenneth G.  Paterson and Bertram Poettering and Jacob C. N.  Schuldt},
      title = {Plaintext Recovery Attacks Against WPA/TKIP},
      howpublished = {Cryptology ePrint Archive, Paper 2013/748},
      year = {2013},
      note = {\url{}},
      url = {}
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