Even before they added all the data collection and cloud storage 'sealed sender' didn't do much to protect users.
"Even under the sealed sender, observers said, Signal will continue to map senders' IP addresses. That information, combined with recipient IDs and message times, means that Signal continues to leave a wake of potentially sensitive metadata. Still, by removing the "from" information from the outside of Signal messages, the service is incrementally raising the bar." (https://arstechnica.com/information-technology/2018/10/new-s...)
A couple years after that "incremental" improvement Signal started keeping everything forever in the cloud which means that today governments can get a signal user's information just by brute forcing a PIN
Even before they added all the data collection and cloud storage 'sealed sender' didn't do much to protect users.
"Even under the sealed sender, observers said, Signal will continue to map senders' IP addresses. That information, combined with recipient IDs and message times, means that Signal continues to leave a wake of potentially sensitive metadata. Still, by removing the "from" information from the outside of Signal messages, the service is incrementally raising the bar." (https://arstechnica.com/information-technology/2018/10/new-s...)
A couple years after that "incremental" improvement Signal started keeping everything forever in the cloud which means that today governments can get a signal user's information just by brute forcing a PIN