The Defence Signals Directorate (DSD) has authorised the use of Apple devices running the iOS 5 operating system to communicate and store classified information up to the 'protected' level in Federal Government.
The decision caps a long-running ban on the use of Apple devices for government personnel dealing in classified information.
DSD acting director Mike Burgess said the formal security evaluation of iOS 5 was "the first of its kind" and was intended for agencies that implemented security advice from the organisation.
Defence has also updated hardening guidelines for government use of iOS devices [pdf]. It released the guidelines in July last year covering hardware with the iOS 4 system as part of its assessment process.
The revised guidelines urged agencies to ensure apps used in unclassified environments take advantage of the security features in iOS 5.
"This is particularly important, as at the time of this publication, the only native application making full use of data protection within iOS 5 is Mail," the DSD said.
It noted that devices dealing in information at the 'protected' classification level "should not allow user installation of Apps".
Likewise, use of iCloud is out for devices used for such information.
iCloud use in unclassified settings was left to agency assessment and discretion.
The DSD recommended Apple device users not be given permissions to create separate email accounts in a bid to stop them cut-and-pasting data into public email accounts.
It also recommended agencies "restrict access to webmail, disable screen shots on device and filter sensitive mail or attachments" to further reduce risk.
There are already Apple projects underway within Defence. Last month, iTnews revealed that the Australian Army's Forces Command has deployed 80 Apple iPads and 80 Samsung Galaxy tablets to aid training of new recruits.
However, use of these devices in these settings is likely to be restricted to communication and use of unclassified information.