SHA-2 was designed and developed by the National Security Agency (NSA) and is today one of the hash algorithms where still no collisions have been found. SHA-2 was created because of the weakness of SHA-1 where a simple step was missing. SHA-2 takes the last bitgroup and after some bit operations the group will be placed at the beginning. It has been shown that this step makes SHA-2 very robust against attacks. SHA-2 can be used with different bit length: SHA-256, SHA-384 and SHA-512.