What is Signal, the messaging app Trump team used to share war plans?

Thomson Reuters

· Posted: Mar 25, 2025 11:40 AM EDT | Last Updated: 10 minutes ago

Top Trump medication officials utilized messaging app Signal to stock warfare plans and mistakenly included a writer successful the encrypted chat, spurring calls by Democratic lawmakers for a legislature probe into the information breach.

Under U.S. law, it tin beryllium a transgression to mishandle, misuse oregon maltreatment classified information, though it is unclear whether those provisions mightiness person been violated successful this case.

Jeffrey Goldberg, editor-in-chief of The Atlantic, said successful a study connected Monday that nationalist information advisor Mike Waltz accidentally added him connected March 13 to an encrypted chat radical connected the Signal messaging app co-ordinating U.S. enactment against Yemen's Houthi rebel radical implicit its attacks connected Red Sea shipping.

Democrats — and immoderate of Trump's chap Republicans — called for an probe of what appeared to beryllium a large information breach. Classified and delicate accusation is not expected to beryllium shared connected commercialized mobile telephone apps, and chartless numbers — specified arsenic Goldberg's — should not beryllium included.

Below are immoderate of the main facts astir Signal:

How does Signal work?

Signal is simply a unafraid messaging work that uses end-to-end encryption, meaning the work supplier cannot entree and work backstage conversations and calls from users connected its app, truthful guaranteeing its users' privacy.

Signal's bundle is disposable crossed platforms, some connected smartphones and computers, and enables messaging, dependable and video calls. A telephone fig is indispensable to registry and make an account.

Unlike different messaging apps, Signal does not way oregon store idiosyncratic data, and its codification is publically available, truthful information experts tin verify however it works and guarantee it remains safe.

How harmless is it?

Signal is an open-source and afloat encrypted messaging work that runs connected centralized servers maintained by Signal Messenger.

The lone idiosyncratic information it stores connected its servers are telephone numbers, the day a idiosyncratic joined the service and the past login information.

Users' contacts, chats and different communications are alternatively stored connected the user's phone, with the anticipation of mounting the enactment to automatically delete conversations aft a definite magnitude of time.

The institution uses nary ads oregon affiliate marketers, and doesn't way users' data, arsenic stated connected its website.

Signal besides gives users the anticipation to fell their telephone fig from others and usage an further information fig to verify the information of their messages, it adds.

Signal does not usage U.S. authorities encryption oregon that of immoderate different governments, and is not hosted connected authorities servers.

"All indications constituent towards Signal arsenic 1 of the astir trusted and unafraid services for communication," said PP Foresight expert Paolo Pescatore. "This is intelligibly underlined by the usage wrong the U.S. government."

Who founded Signal?

Signal was founded successful 2012 by entrepreneur Moxie Marlinspike and its existent president is Meredith Whittaker, according to the company's website.

In February 2018, Marlinspike alongside WhatsApp co-founder Brian Acton started the non-profit Signal Foundation, which presently oversees the app. Acton provided an archetypal backing of $50 cardinal US.

Acton near WhatsApp successful 2017 owed to differences astir the usage of lawsuit information and targeted advertising.

Signal is not tied to immoderate large tech companies and volition ne'er beryllium acquired by one, it says connected its website.

Who uses Signal?

Widely utilized by privateness advocates and governmental activists, Signal has gone from an exotic messaging app utilized by dissidents to a susurration web for journalists and media, to a messaging instrumentality for authorities agencies and organizations.

Signal saw "unprecedented" maturation successful 2021 aft a disputed alteration successful rival WhatsApp's privateness terms, arsenic privateness advocates jumped disconnected WhatsApp connected fears users would person to stock their information with some Facebook and Instagram.

Reuters lists Signal arsenic 1 of the tools tipsters tin usage to stock confidential quality tips with its journalists, portion noting that "no strategy is 100 per cent secure."

Signal's assemblage forum, an unofficial group, which states that its medication is composed of Signal employees, besides lists the European Commission arsenic a idiosyncratic of the tool.

In 2017, the U.S. Senate sergeant astatine arms approved the usage of Signal for Senate staff.

"Although Signal is wide regarded arsenic offering precise unafraid communications for consumers owed to its end-to-end encryption and due to the fact that it collects precise small idiosyncratic data, it is hard to judge it is suitable for exchanging messages related to nationalist security," said Ben Wood, main expert astatine CCS Insight — alluding to the breach involving apical Trump aides discussing plans for subject strikes connected Yemeni Houthi militants.

Google's connection services Google Messages and Google Allo, arsenic good arsenic Meta's Facebook Messenger and WhatsApp, usage the Signal Protocol, according to Signal's website.