Patent ID: 8831569

Claim:
A method at a server for handling delivery of messages to a recipient device associated with the server, the method comprising: receiving, from a sender system external to the server, a message at the server, the message as received including a digital signature calculated using a private key associated with a certificate of a sender and appended thereto by the sender system; determining at the server whether the message as received exceeds a size limit; when the message as received exceeds the size limit, verifying the digital signature at the server using the certificate prior to the server providing any part of the message including the digital certificate to the recipient device; providing at least a portion of the message and a result of the verifying of the digital signature to the recipient device; and providing certificate identifying information for the certificate to the recipient device for use by the recipient device in carrying out a further verification; and when the message as received does not exceed the size limit, the server provides the at least a portion of the message to the recipient device without carrying out the verifying the digital signature prior to providing the at least a portion of the message to the recipient device.