A simple power analysis attack against the key schedule of the Camellia block cipher

This paper presents a simple power analysis attack against the key schedule of Camellia. The attack works for the smart card environment which leaks the Hamming weight of data being processed, making use of the Hamming weight to deduce all key bits. It is shown that determining the cipher key given accurate power analysis data is very fast and does not require any pair of plaintext and ciphertext.