Explore practical applications of homomorphic encryption in this 54-minute lecture by Hao Chen from Microsoft Research. Delve into the fundamentals of homomorphic encryption, its use cases, and performance benchmarks. Learn about Oblivious RAM with O(1) communication through the Onion Ring ORAM architecture. Examine optimizations in oblivious permutation and eviction. Gain insights into Multi-Key Homomorphic Encryption (MKHE) over rings, focusing on relinearization key generation and new relinearization techniques. Discover the implementation of MNIST inference using the SPDZ framework, including optimizations for matrix triple generation and authenticated share creation. Conclude with an overview of Microsoft SEAL 3.5 and its matrix multiplication performance.