A technique, and system(s) implementing the technique, allow an encrypted message
to be sent directly to a recipient, and when the recipient opens the message, the
recipient's system sends a request to an arbiter server to retrieve decryption
information to decrypt the message. When the arbiter server receives the request
for the decryption information, the arbiter server generates evidence of the request
and sends the decryption information to the recipient. In this way, an evidentiary
trail, that cannot be repudiated, can be used to establish that the recipient received
and attempted to open the message.
