Explore new attacks on concatenation and XOR hash combiners in this 24-minute conference talk presented by Itai Dinur at Eurocrypt 2016. Delve into cryptographic hash functions, focusing on concatenating and iterated hash functions. Examine the evolution of hash function attacks from 2003 to 2015, including Joux's work in 2004 and Kelsey and Schneier's contributions in 2005. Analyze second preimage attacks on MD and concatenated MD hash functions. Investigate a novel approach using deep iterates, understand the proposed algorithm, and consider the implications for hash function security.