GSM Crack Paper

[John Young]

"Instant Ciphertext-Only Cryptanalysis of GSM Encrypted
Communications," by Elad Barkan, Eli Biham, Nathan Keller

  http://cryptome.org/gsm-crack-bbk.pdf  (18 Pages, 234KB)

Abstract. In this paper we present a very practical cipher-text only
cryptanalysis of GSM encrypted communications, and various active
attacks on the GSM protocols. These attacks can even break into
GSM networks that use "unbreakable" ciphers. We describe a
ciphertext-only attack on A5/2 that requires a few dozen milliseconds
of encrypted off-the-air cellular conversation and finds the correct
key in less than a second on a personal computer. We then extend
this attack to a (more complex) ciphertext-only attack on A5/1. We
describe new attacks on the protocols of networks that use A5/1, A5/3,
or even GPRS. These attacks are based on security flaws of the GSM
protocols, and work whenever the mobile phone supports A5/2. We
emphasize that these attacks are on the protocols, and are thus
applicable whenever the cellular phone supports a weak cipher, for
instance they are also applicable using the cryptanalysis of A5/1.
Unlike previous attacks on GSM that require unrealistic information,
like long known plaintext periods, our attacks are very practical and
do not require any knowledge of the content of the conversation.
These attacks allow attackers to tap conversations and decrypt
them either in real-time, or at any later time. We also show active
attacks, such as call hijacking, altering data messages and call
theft.


---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo at metzdowd.com