Bit-flipping attack

A bit-flipping attack is an attack on a cryptographic cipher in which the attacker can change the ciphertext in such a way as to result in a predictable change of the plaintext, although the attacker is not able to learn the plaintext itself. Note that this type of attack is not -- directly -- against the cipher itself (as cryptanalysis of it would be), but against a particular message or series of messages. In the extreme, this could become a Denial of service attack against all messages on a particular channel using that cipher.

The attack is especially dangerous when the attacker knows the format of the message. In such a situation, the attacker can turn it into a similar message but one in which some important information is altered. For example, a change in the destination address might alter the message route in a way that will force re-encryption with a weaker cipher, thus possibly making it easier for an attacker to decipher the message.

When applied to digital signatures, the attacker might be able to change a promissory note stating "I owe you $10.00" into one stating "I owe you $10000".

Stream ciphers, such as RC4, can be vulnerable to a bit-flipping attack. Ciphers with good diffusion properties are generally resistant to it.Fact|date=February 2007 Adding a message authentication code to the message is a standard way of increasing resistance of a cipher to a bit-flipping attack.

External links

* [http://www.cisco.com/en/US/netsol/ns339/ns395/ns176/ns178/networking_solutions_white_paper09186a00800b469f.shtml Wireless LAN Security White Paper]