Secure Computation and Homomorphic Encryption — Computing on Data You Can't See
What if you could compute on data while it stays encrypted the entire time — never decrypting it, never seeing it, yet getting the correct result? It sounds impossible, but cryptography makes it real. Homomorphic encryption and secure multi-party computation let parties jointly compute on sensitive data that none of them can read, closing the one gap the other privacy techniques leave open: protecting data even during the computation itself. This post covers the most mathematically remarkable tools in the privacy toolkit.
What if you could compute on data while it stays encrypted, never seeing it, yet get the right result? Homomorphic encryption (math on ciphertext — private inference) and secure multi-party computation (secret sharing — the basis of secure aggregation) close the gap of protecting data in use — the strongest and most expensive tools.