Signal app used in US military chats has triggered a major controversy after reports revealed senior officials coordinated air strikes in Yemen through private Signal groups. In March, the White House confirmed that officials discussed the attacks in a Signal chat that accidentally included journalist Jeffrey Goldberg. In April, reports showed US Defence Secretary Pete Hegseth shared updates in a separate group that included his wife, brother, and lawyer.
Signal, created by Matthew Rosenfeld—also known as Moxie Marlinspike—offers end-to-end encryption that prevents even the app itself from reading messages. With 40–70 million monthly users, it ranks small compared to WhatsApp and Messenger but attracts high-profile users due to its privacy features.
The app’s code is open-source, allowing independent experts to audit it for weaknesses. Signal collects minimal user data and operates as a nonprofit, relying on donations instead of advertising. Cybersecurity professionals often prefer it for its transparency and strong encryption.
Despite these strengths, experts warn that mobile apps aren’t suitable for top-level government discussions. Devices used for national security can still be compromised, regardless of encryption. A person who unlocks the phone gains full access to Signal chats. In public places, anyone nearby can view messages or monitor conversations.
Caro Robson, a data security specialist with experience in US federal systems, explained that senior officials normally use SCIFs—secure rooms that block unauthorized access. These rooms prevent digital surveillance and prohibit personal devices. SCIFs also follow strict access protocols and use advanced government encryption.
Disappearing messages have raised further concerns. Signal lets users auto-delete messages after a set time. Goldberg noted that some messages in his group vanished after a week. Unless officials manually archived these chats, they may have violated US record-keeping laws. Federal policies require that government communications remain accessible for historical and legal review.
Encrypted messaging has long sparked debate among lawmakers. Governments have pushed for backdoors to monitor threats. Signal and WhatsApp oppose such efforts, arguing they weaken security for all users. Signal previously threatened to leave the UK if privacy laws forced changes to its encryption model.
Apple also dropped a cloud encryption feature in the UK this year after similar government pressure. These events highlight the ongoing battle between user privacy and state surveillance demands.
The Signal leaks have now led to calls for a formal investigation. Lawmakers, including Senate leader Chuck Schumer, described the incident as one of the most serious military intelligence breaches in recent history. As secure apps become common tools, the line between personal tech and public duty continues to blur in sensitive spaces.
