HPKE: Standardizing public-key encryption (finally!)

For the last three years, the Crypto Forum Research Group of the Internet Research Task Force (IRTF) has been working on specifying the next generation of (hybrid) public-key encryption (PKE) for Internet protocols and applications. The result is Hybrid Public Key Encryption (HPKE), published today as RFC 9180.
HPKE was made to be simple, reusable, and future-proof by building upon knowledge from prior PKE schemes and software implementations. It is already in use in a large assortment of emerging Internet standards, including TLS Encrypted Client Hello and Oblivious DNS-over-HTTPS, and has a large assortment of interoperable implementations, including one in CIRCL. This article provides an overview of this new standard, going back to discuss its motivation, design goals, and development process.
A primer on public-key encryption
Public-key cryptography is decades old, with its roots going back to the seminal work of Diffie and Hellman in 1976, entitled “New Directions in Cryptography.” Their proposal – today called Diffie-Hellman key exchange – was a breakthrough. It allowed one to transform small secrets into big secrets for cryptographic applications and protocols. For example, one can bootstrap a secure channel for exchanging messages with confidentiality and integrity using a key exchange Continue reading