Get the Whitepaper called Biclique Cryptanalysis of the Full AES. Since Rijndael was chosen as the Advanced Encryption Standard, improving upon 7-round attacks on the 128-bit key variant or upon 8-round attacks on the 192/256-bit key variants has been one of the most difficult challenges in the cryptanalysis of block ciphers for more than a decade. This paper discusses shortcut attacks on AES.
You can download it from the following link: https://packetstormsecurity.com/files/download/104224/aesbc.pdf
Source: https://packetstormsecurity.com/files/104224/Biclique-Cryptanalysis-Of-The-Full-AES.html