With the system receiving 80,000 messages and sending some 300,000 each day, Harrison stressed how critical it is for Customs to ensure the integrity of the system is upheld.

"I came into this thing in 2002 and we were bedding down ID management [and] it's bloody difficult," he said. "You've got other systems for ID management, but not for non-repudiation; PKI was the only tech available."

While conceding the legal framework around digital certificates is an "expensive and difficult process", Harrison said they do work once an organization is "over the hump" of convincing its industry partners to comply.

The Gatekeeper framework (the Australian government's strategy for the use of Public Key Infrastructure (PKI) as a key enabler for the delivery of online government services) was designed to be a generic entry system for government, but to move goods across the border a person must be responsible for identifying themselves by becoming an authorized agent for digital certificates within the organization.

Internally, Customs took the opportunity to review its own identity management infrastructure, which is required to cope with four different levels of authentication amid about 17,000 business rules.