A non-transitory computer-readable storage medium comprising instructions stored thereon. When executed by at least one processor, the instructions may be configured to cause a computing system to at least receive a message, the message including a header, an encrypted symmetric key, and an encrypted body, decrypt the encrypted symmetric key using a private key to generate a decrypted symmetric key, decrypt the encrypted body using the decrypted symmetric key to generate a decrypted body, and store the header, the decrypted symmetric key, and the decrypted body in long-term storage.