HPKE
HPKE, or Hybrid Public Key Encryption, is a cryptographic standard designed to provide authenticated encryption for data. It allows one party to encrypt data for another party, ensuring that only the intended recipient can decrypt it and that the sender's identity is verifiable. HPKE combines several cryptographic primitives to achieve this goal. At its core, HPKE uses a public-key encryption scheme to establish a shared secret key. This public-key mechanism can be chosen from various options, such as RSA or Elliptic Curve Integrated Encryption Scheme (ECIES). Once a shared secret is established, it is then used with a symmetric encryption algorithm, like AES, to encrypt the actual data. This hybrid approach leverages the efficiency of symmetric encryption for bulk data while using public-key cryptography for secure key establishment.
In addition to confidentiality, HPKE also provides authenticated encryption. This means that not only is the