Related-key Cryptanalysis of Full AES-192 and AES-256

Cryptoanalysts Alex Biryukov and Dmitry Khovratovich have released a paper describing their work on an attack against full AES-192 and AES-256. The paper details the first key recovery attack that works for all keys and has a complexity less than brute force.

The attack against AES-256 reduces the complexity down to 2^119, the attack is based on a previous boomerang attack against AES-192 that has been enhanced using boomerang switching techniques.

The paper released here details attacks against both AES-192 and AES-256, the attacks are based on the recent idea of find local collisions in block ciphers. The notion of a local collision is derived from the cryptanalysis of hash functions. The paper fully describes the concept when attacking AES.

Although the published attack does reduce the complexity required to recover the key used to encrypt something with AES, it does not result in a complexity that is within the easy reach of current technology. Therefore it is not right to say that AES is broken fully, it just means there is an attack that is better than brute force, and would still take a significant period of time to recover the key.