The initialization vector in WEP is a 24-bit field, which is sent in The checksum so that the resulting message appears valid. To flip arbitrary bits in an encrypted message and correctly adjust Because flippingīits carries through after an RC4 decryption, this allows the attacker Produce a correct checksum on the modified message. In a deterministic set of bits in the CRC that must be flipped to In other words, flipping bit n in the message results Of two CRCs based on the bit difference of the messages over which Linear, which means that it is possible to compute the bit difference Is part of the encrypted payload of the packet. The integrity check field is implemented as a CRC-32 checksum, which Implemented incorrectly, resulting in poor security. Shared secret key and produce a different RC4 key for each packet. Same key stream, an Initialization Vector (IV) is used to augment the To avoid encrypting two ciphertexts with the Packet has not been modified in transit, it uses an Integrity Check WEP has defenses against both of these attacks. Once one of the plaintexts becomes known, it is trivial to recover all Practical as more ciphertexts that use the same key stream are known. The statistical attacks become increasingly Knowledge of this XOR can enable statistical attacks to Same key stream, it is possible to obtain the XOR of the two If an attacker flips a bit in the ciphertext, then uponĭecryption, the corresponding bit in the plaintext will be flipped.Īlso, if an eavesdropper intercepts two ciphertexts encrypted with the This mode of operation makes stream ciphers vulnerable to severalĪttacks. Stream with the ciphertext yields the original plaintext. Same key, and uses it to generate identical key stream. A stream cipher operates by expanding a short key into an WEP uses the RC4 encryption algorithm, which is known as a streamĬipher. Of traffic, allows real-time automated decryption of all traffic.Īn excerpt from their paper about the technical problems with WEP: Active attack to inject new traffic from unauthorized mobile stations, based on known plaintext.Īctive attacks to decrypt traffic, based on tricking the accessĭictionary-buildingattack that, after analysis of about a day's worth.Passive attacks to decrypt traffic based on statistical analysis.
In 2001, 3 researchers working at Berkeley produced a paper named " (In)Security of the WEP algorithm". Unfortunately it was discovered that WEP had some serious flaws. WEP was the first algorithm used to secure wireless access points. Mostly on consumer wireless access points these are: There are several types of possible encryption. First of all that would entirely depend on the encryption used by the access point.
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