Explore a groundbreaking approach to hashing five inputs with only three compression calls in this 22-minute conference talk from the 2021 ITC Conference. Dive into the innovative T5 construction, which achieves Stam's bound with improved collision and preimage security. Learn how this method offers a 25% reduction in compression function calls compared to traditional hash function constructions, and discover its applications in sequential Merkle-Damgård hashing and a novel Merkle tree variant. Examine the benefits of parallel execution units, and understand the trade-offs between conservative and aggressive local opening modes. Gain insights into the potential for enhanced efficiency in hashing algorithms and their implications for cryptographic systems.