Function seal_payload 

pub fn seal_payload(
    plaintext: &[u8],
    storers: Vec<String>,
) -> Result<(EncryptedCommonsPayload, DataKey), String>

Seal a plaintext payload. Generates a random DEK, AEAD-encrypts under it, and content-addresses the ciphertext. Returns the replicable EncryptedCommonsPayload and the DEK (to be sealed per recipient by wrap_dek_to, then dropped — do not persist it in the clear).