What is Signal, the app Trump officials used for Yemen strike talks?

Trump officials used encrypted app Signal for Yemen strike talks, mistakenly adding a journalist, sparking national security concerns and calls for investigation

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An encrypted messaging app, Signal, is at the centre of controversy after top Trump administration officials, including Defence Secretary Pete Hegseth and Vice President JD Vance, allegedly used it to discuss a highly sensitive military operation. The discussions reportedly took place in a Signal group chat that inadvertently included The Atlantic's editor-in-chief, Jeffrey Goldberg.

 

On Monday, Goldberg published an article revealing that he was mistakenly added to an 18-person Signal chat discussing military strikes in Yemen. Initially, he found it hard to believe, writing, "I didn't think it could be real."

 

The National Security Council later confirmed to CBS News that the messages "seem to be authentic." The revelation has sparked major concerns about the security of Signal and its use for discussing classified military operations.

 

On Wednesday (IST), US President Donald Trump addressed the issue, stating he had directed national security adviser Mike Waltz, who Goldberg claims added him to the chat, to "immediately study" the use of Signal by government officials.

 

What is Signal?

 

Signal is a widely used encrypted messaging app that allows for text messaging, voice and video calls, and large group chats of up to 1,000 people. Users can also set messages to disappear after a certain time. The app is favoured for its end-to-end encryption, which ensures that only the sender and recipient can access message content, making it a go-to choice for privacy-conscious users.

 

Unlike Telegram, another encrypted messaging app, Signal's encryption is enabled by default, and the platform claims it does not collect or store user data. "Signal messages and calls cannot be accessed by us or other third parties because they are always end-to-end encrypted, private, and secure," the company states.  ALSO READ | US Senate to question intelligence officials after war plans leak

 

Who owns Signal?

 

Signal is owned by the nonprofit Signal Foundation, established by Moxie Marlinspike and Brian Acton. Acton, a WhatsApp co-founder, donated $50 million to support the foundation's operations. Signal positions itself as an independent, ad-free, and investor-free platform sustained only by donations from users.

 

Can Signal be hacked?

 

While Signal is widely regarded as more secure than traditional texting, experts caution that no platform is entirely hack-proof. In February 2025, the National Security Agency (NSA) issued an internal bulletin warning employees of vulnerabilities in Signal.

 

"The use of Signal by common targets of surveillance and espionage activity has made the application a high-value target to intercept sensitive information," the bulletin stated, according to CBS News.  ALSO READ | Trump says security team texting military op plan on Signal a minor glitch

 

Signal responded via social media, clarifying that the NSA's concerns were related to phishing scams targeting users rather than flaws in Signal’s encryption technology.

 

Trump, lawmakers, and the fallout

 

Trump distanced himself from the controversy, telling reporters on Tuesday, "I don't know anything about Signal, I wasn't involved in this." However, he acknowledged that the app is widely used, adding, "I hear it's used by a lot of groups, the media, and even the military. Sometimes people can get onto those things—that’s one of the prices you pay when you're not in the Situation Room."

 

Meanwhile, Democratic lawmakers are calling for an investigation into why sensitive national security discussions were taking place on a commercially available messaging app rather than secure government channels.  ALSO READ | There was no classified information: Gabbard on Yemen strikes chat leaks

 

Adding to concerns, Goldberg reported that some messages in the Signal group chat were set to disappear after one week, while others were scheduled to vanish after four weeks. This practice could potentially violate federal laws requiring the preservation of official records.

 

(With AP inputs)