Signal Messenger (Signal) which is developed by the Open Whisper System markets itself as an “end to end”, “secure” communications platform that is open source and the organization and/or it’s employees are unable to read your messages.

However, how much knowledge do they store? What could be accessed by a legal search warrant and/or subpoena? Thankfully a 2016 federal subpoena sheds some light on this. 

Here the government was asking for two accounts and from those two accounts they wanted to know IP addresses, IP history, name, address, payment details, etc. So what data was Signal able to provide? 

One phone number apparently they had no records. The other number the only data they could provide was the time the account was created in Unix time and the date of the last connection in Unix time. That’s it. Nothing else was redacted. This is the full list of all that could be provided based on the broad request. 

The best predictor of future action is what has happened in the past. Here we have official court documents which show exactly was producible. Given what these documents show and the fact this platform is an open source we feel quite confident this platform is close to “zero-knowledge“.  

For complete source document click here.