Abstract: Secure communication of payload data is provided from a server system to a destination system used by a recipient. The recipient is associated with a key pair including a public key and a private key, the private key being protected by a password or passphrase of the recipient. The server system generates and sends a conveyance message to the destination system. The conveyance message contains at least the payload data encrypted using a payload key. After receipt of the conveyance message, the destination system prompts the recipient for his or her password or passphrase. The server system uses the recipient's password or passphrase to access the recipient's private key, and then uses the private key to decrypt the encrypted version of the payload key. The server system sends the payload key to the destination system, and the destination system in turn uses the payload key to decrypt the payload data.

Abstract: A method is provided for secure communication of payload data PD from a server system 10 to a destination system 12 used by a recipient. The recipient is associated with a key pair 20 comprising a public key U and a private key V, the private key V being protected by a password or passphrase W of the recipient. The server system 10 generates and sends a conveyance message CM to the destination system 12. The conveyance message CM comprises at least an encrypted version of the payload data PD encrypted using a payload key S. After receipt of the conveyance message CM, the destination system 12 prompts the recipient for his or her password or passphrase W. The destination system 12 then generates and sends a return message RM to the server system 10. The return message RM comprises at least the recipient's password or passphrase W.