International Association
for Cryptologic Research

SHA-2 (SHA-224, SHA-256, SHA-384 and SHA-512) is hash function family issued by the National Institute of Standards and Technology (NIST) in 2002 and is widely used all over the world. In this work, we analyze the security of SHA-512 with respect to boomerang attack. Boomerang distinguisher on SHA-512 compression function reduced to 48 steps is proposed, with a practical complexity of $2^{51}$. A practical example of the distinguisher for 48-step SHA-512 is also given. As far as we know, it is the best practical attack on step-reduced SHA-512.