Since the discovery of collision attacks against several well-known cryptographic hash functions in 2004, a rush of new cryptanalytic results cast doubt on the current hash function standards. The relatively new NIST SHA-2 standards aren't yet immediately threatened, but their long-term viability is now in question. The US National Institute of Standards and Technology (NIST) has therefore begun an international competition to select a new SHA-3 standard. This article outlines the competition, its rules, the requirements for the hash function candidates, and the process that NIST will use to select the final winning SHA-3 standard.