The encrypted messaging application Signal has recently become a focal point of discussion following revelations that top officials from the Trump administration, including Defense Secretary Pete Hegseth and Vice President JD Vance, engaged in its use to deliberate on sensitive military operations. An unexpected twist ensued when The Atlantic’s editor-in-chief, Jeffrey Goldberg, was inadvertently included in a chat among 18 participants.

Goldberg recounted his experience in a Monday article for The Atlantic, expressing skepticism about the authenticity of the chat upon his initial inclusion. Upon investigation, the National Security Council confirmed the authenticity of the messages exchanged in this chat.

What Is Signal?

Signal is a versatile encrypted messaging service that supports not just text messaging but also voice and video calls. The app can accommodate group chats of up to 1,000 members and allows users to set messages to disappear after a designated timeframe.

As a result of its strong end-to-end encryption, Signal has seen a significant uptick in users, with approximately 70 million registered in 2024, a comparatively small number next to Apple’s iMessage, which boasts around 1 billion monthly active users, as reported by Lawfare.

“Signal’s appeal has surged in times of uncertainty or in the face of events that highlight the need for secure communication,” noted Paolo Pescatore, an analyst at PP Foresight, in a statement to CBS MoneyWatch. Signal guarantees that conversations remain private and secure, claiming that messages and calls are encrypted to the point that neither the service nor any third party can access them.

Ownership and Background

Signal operates under the nonprofit Signal Foundation, co-founded by Moxie Marlinspike and Brian Acton, who launched the foundation to support its operations and explore the future of private communication. The foundation is funded solely by donations from users, lacking advertising or investment pressures.

The app itself was developed over ten years ago by Marlinspike, who previously sold his mobile security startup to Twitter. His initiative merged two existing open-source applications—one for messaging and another for calls—into the Signal we know today.

Security Considerations

While Signal emphasizes its privacy features, experts caution that no system is invulnerable. Although government officials have adopted Signal for organizing sensitive meetings, there are recommendations for cautious use, as some officials in the Biden administration were directed to minimize reliance on the app.

“Signal presents a robust suite of features compared to standard messaging apps, but vulnerabilities can always be exploited by determined hackers,” Pescatore remarked.

Typical Use Cases

Signal has gained popularity among national security professionals and activists due to its strong encryption measures. A recent review by the Associated Press highlighted that encrypted messaging applications like Signal are becoming increasingly favored among government officials, with some utilizing personal phone numbers for registration.

Legal Implications for Government Officials

The use of Signal by government officials to exchange classified information raises potential legal concerns. Sam Vinograd, a national security contributor for CBS News and a former official in Barack Obama’s administration, cautioned that such communications could lead to breaches of the Espionage Act. He remarked, “Using a nonsecure platform like Signal for classified exchanges elevates the risk of unauthorized access to sensitive operational plans, endangering both national security and military personnel.”

Additionally, queries have emerged from Democratic lawmakers, demanding scrutiny of why crucial information was on a commercially available app rather than secure government channels. Goldberg reported that some messages in the chat were set to auto-delete, which could infringe upon federal record-keeping laws.