Citrix Systems, Inc.
Secure message passing using semi-trusted intermediaries

Abstract:

Techniques are provided for secure message passing. A sender process has a clear (non-encrypted) text message to pass to a recipient process as an encrypted message. The sender generates a message encryption key (MEK) for encrypting the message and sends the MEK to a first intermediary process, which encrypts the MEK. The sender uses the MEK to encrypt the message and passes both the encrypted message and the encrypted MEK to a second intermediary process. The second intermediary verifies that the sender is authorized to send messages and retains the encrypted message and the encrypted MEK. The second intermediary passes the encrypted message and the encrypted MEK to the recipient, which requests decryption of the encrypted MEK from the first intermediary. The first intermediary then decrypts the MEK and returns it to the recipient. Finally, the recipient decrypts the message using the MEK.