Signal must do something right.
"The top justice officials of the United States, Britain, Australia, Canada and New Zealand said in a statement that the growth of end-to-end encrypted apps that make official oversight impossible – like Signal, Telegram, FaceBook Messenger and WhatsApp – “pose significant challenges to public safety.” https://www.euractiv.com/section/cybersecurity/news/five-eye...
https://www.justice.gov/opa/pr/international-statement-end-e...
>definitely backdoored given the agencies who choose to use it
Agencies who know about backdoor use different app and promote the backdoored app to others and use secure app themselves. Sounds more logical, yeah?
So aus officials have legislation at hand where they can get any app that operates here in aus, backdoored at their request. The company and anyone involved in the process is up for serious jail time if they divulge their part in the backdoor implementation to anyone.
Signal, whilst it's partially open doesn't mean it's not backdoored.