By James Pearson

LONDON, March 25 (Reuters) - The president of Signal defended the messaging app's security on Wednesday after top Trump administration officials mistakenly included a journalist in an encrypted chatroom they used to discuss a looming U.S. attack on Yemen's Houthis.

Signal's Meredith Whittaker did not directly address the blunder, which Democratic lawmakers have said was a breach of U.S. national security. But she described the app as the "gold standard in private comms" in a post on X, which outlined Signal's security advantages over Meta's WhatsApp messaging app.

"We’re open source, nonprofit, and we develop and apply (end-to-end encryption) and privacy-preserving tech across our system to protect metadata and message contents," she said.

Signal has been growing in popularity in Europe and the United States as an alternative to WhatsApp because it collects very little data about its users.

According to data from Sensor Tower, a market intelligence firm, U.S. downloads of Signal in the first three months of 2025 were up 16% compared to the prior quarter, and 25% compared to the same period in 2024.

In a February interview with De Telegraaf, a Dutch newspaper, Whittaker said Signal was a safer alternative because WhatsApp collects metadata which can be used to see who messages whom, and how often.

"When compelled, like all companies that collect the data to begin with, they turn this important, revealing data over," Whittaker said in her post on X.

Meta did not immediately respond to an emailed request for comment.

(Reporting by James Pearson; additional reporting by Katie Paul in New York; editing by Mark Heinrich)