Dear Australia. I love you, but this is completely impossible:
“Here’s a short summary of the new powers the legislation hands over to law enforcement and national security agencies:
The law enables Australia’s attorney-general to order the likes of Apple, Facebook, and Whatsapp to build capability, such as software code, which enables police to access a particular device or service.
Companies may also have to provide the design specifications of their technology to police, facilitate access to a device or service, help authorities develop their own capabilities and conceal the fact that an agency has undertaken a covert operation.”
If it can be decrypted by the company that created the technology, then it is not secure. Period. End of discussion.