"The instruction appeared on internal messaging boards in early February, notifying employees that "Signal has been selected as the recommended application for public instant messaging."
The app is favored by privacy activists because of its end-to-end encryption and open-source technology.
"It's like Facebook's WhatsApp and Apple's iMessage but it's based on an encryption protocol that's very innovative," said Bart Preneel, cryptography expert at the University of Leuven. "Because it's open-source, you can check what's happening under the hood," he added.
Itt's not to say that Signal is the most secure messenger out there but it is probably the most well known secure one. It's infrastructure is under US jurisdiction but they have never been implicated in handing data over to authorities and cannot read the data (although the servers could be shut off). Better options such as Wire, Threema, and Wickr do start getting a little more technical, and if you want to go deeper still you head into peer-to-peer encrypted messaging without central servers (such as Tox, Briar, and Jami) but that may be a bit heavy for public officials to use... I suppose Signal is the simplest and easiest change to make.
Signal is now the messaging app of choice for the European Commission. The messaging app has been praised for its security prioritization, as well as the simplicity and ease of use. For similar reasons, the UK Conservative Party made the switch in December.