The Islamic State has long relied on messaging apps like Facebook’s fb What’sApp, Telegram, and Twitter twtr direct messaging to communicate and distribute propaganda. Now, online counterterrorism outfit Ghost Security Group claims ISIS has built its own Android-based, encrypted messaging app that circumvents conventional messaging apps like WhatsApp that are easier for the F.B.I. to monitor.

Ghost Security is the same hacking collective that last month pointed out that ISIS members used Telegram—a secure messaging app created by a Russian developer now living in Germany—to ultimately download an another app called Amaq Agency. That app, run by a group of the same name with ties to ISIS, provided users with a stream of news and videos filled with ISIS propaganda messages including executions, battlefield footage, and speeches.

The site hosting the Amaq Agency app download has since disappeared. Shortly thereafter another app surfaced in its place called Alrawi.apk. The Alrawi app behaves much like the Amaq Agency app before it, but earlier this week Ghost Security operatives discovered what a representative described to DefenseOne as “encrypted communications features” that lets users securely swap messages and other digital communications.

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These messaging features aren’t quite as secure or sophisticated as those of Telegram or WhatsApp, but they share the distinct advantage of being independent of any third-party company or organization that might help anti-ISIS governments or law enforcement agencies. In recent months, FBI Director James Comey and others within the U.S. national security apparatus have argued that governments should require services like WhatsApp to build back doors into their encryption so law enforcement can more easily intercept terrorist communications.

Without going quite as far as Comey, President Barack Obama and presidential contenders like Hillary Clinton have in recent weeks urged Silicon Valley to voluntarily join the fight against ISIS. Last month, the president urged technology companies to take steps to limit how terrorists can use their technologies to mask communications and coordinate attacks. The emergence of a messaging app by ISIS complicates those efforts. With its own encrypted messaging app, ISIS doesn’t have to worry about WhatsApp or another of its favorite messaging services letting the FBI or other agencies in.

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Communication has become a cornerstone of ISIS’s operations as the organization has spread not only across Iraq and Syria, but also into Libya, Egypt, and elsewhere in the region. The group has also taken to encouraging so-called “lone wolf” attackers to take up the ISIS cause in their own countries, as seems to have been at least partially the case in December’s San Bernardino, Calif., shootings. Spreading its message through digital channels—both secure and public—has become critically important to the group.

Even when it is not being particularly tech-savvy, ISIS drives home the importance of secure communications to its members and prospective followers. In an attempt to reach out to potential lone wolf attackers in the West and elsewhere, the group has released a booklet of do’s and don’ts for would-be attackers that offers everything from style tips and pointers on men’s fragrances to suggestions on shaving one’s beard. Also included in the booklet: A list of encryption software designed to help users cloak their digital communications.

“Any operation that doesn’t have a strong security and precaution base is deemed to fail, just like a big building needs strong foundations,” the booklet says. “Security precautions are the foundations of any operation.”