Patent ID: 7949355

Claim:
A method of processing attachments to messages sent to a mobile device, the method comprising: after a message to be sent to the mobile device is received by one or more remote servers, receiving data associated with the message at the mobile device from the one or more remote servers; wherein the message comprises a plurality of encrypted attachments; wherein each encrypted attachment has been encrypted using a different one of a plurality of session keys, and each session key has been encrypted with a further encryption key such that the session key is decryptable with the further encryption key that resides on the mobile device and is not available to the remote server; wherein the one or more remote servers are configured to initially withhold transmission of each attachment to the mobile device, and are configured to subsequently transmit an identified attachment to the mobile device if a request for the identified encrypted attachment is received; and wherein the data received at the mobile device comprises data identifying an attachment structure for the message that identifies each of the plurality of attachments by a filename, and further comprises at least one encrypted session key; and outputting the attachment structure at the mobile device.