With hybrid encryption, a symmetric key is generated and used to encrypt the plaintext. The symmetric key is then encrypted with a public key. The payload consists of the ciphertext plus the encrypted symmetric key.
I've come accross a number of different methods for storing the ciphertext+encrypted key payload. one option is to use Json key/values for the base64 encoded ciphertext and encrypted key. Another option is to simply concatenation the ciphertext and encrypted key. PGP also uses a hybrid encryption and has its own file format.
Is there any standard data/file format for storing the result of a hybrid encryption operation besides PGP? It seems like such a format would encourage interoperability.