HPKE

HPKE, defined in RFC 9180, is a modern standard for encrypting data to a recipient's public key by combining a key encapsulation mechanism with an authenticated symmetric cipher. It replaces older ad hoc hybrid encryption constructions with a single well-analyzed design. HPKE is the encryption engine inside TLS Encrypted Client Hello, the Messaging Layer Security (MLS) protocol, and Oblivious HTTP, and it adapts naturally to post-quantum KEMs.