The first fully merged, audited and shipped bit of code from our https://defo.ie project is Hybrid Public Key Encryption (#HKPE RFC9180), it has been shipped by #OpenSSL https://www.openssl.org/blog/blog/2023/10/18/ossl-hpke/ It is a building block for #EncryptedClientHello #ECH and #MessagingLayerSecurity #MLS, providing standard methods for using public key cryptography to encrypt arbitrary blocks of data.