International Association
for Cryptologic Research

The Keccak hash function is a chosen of the SHA-3 competition. This function has the appropriate structural and so far it has been resistant against collision attacks. In the last few years after efforts cryptonalysis, first, the collision in the second round and near collision in the third rounds, was found. and after adi Shamir and Et al succeeded find collision in fourth round and near collision in 5 round for keccak 224,256. In this paper we propose a method that it can used, for any desired text and finds, near collision, in the second round, regardless of any probability. Our attack technique using the find the text that have the same parity such original text in theta function. It is practical for all keccak varies and it finds near collision for second round in few minute. We have named this method \" Parity Analyse\".