President Trump’s presidential transition team is unlikely to receive any awards for transparency. But it may receive applause from some in security circles for its endorsement of Signal, a privacy-focused messaging app that is widely considered to be best in breed.
As Gizmodo reports, internal documents show the transition team sought to arrange for Michael Flynn, an important figure during the early part of the Trump Administration who is now under indictment, to use Signal, which offers untraceable self-destructing messaging features.
The documents were obtained from the General Services Administration (GSA), which is responsible for facilitating the transition of power in the White House. The agency reportedly approved the use of the Signal app in part because of delays in obtaining secure cell phones:
Obtained from the GSA under FOIA by American Oversight, a nonpartisan watchdog group, Trump transition emails reviewed by Gizmodo show that, by the end of November 2016, Flynn had yet to acquire a cellphone that could legally accommodate Secret and Top Secret conversations. However, a variety of services were under consideration: Staff at the Defense Information Systems Agency (DISA), the White House director of technology, as well as a Pentagon project manager overseeing Top Secret data, voice, and video communications, were among those consulted.
“Our IT lead has confirmed that we can install an App on the [Presidential Transition Team] phones called Signal. This will provide secure voice and text,” a GSA employee wrote on November 28th. …
Another transition team member, whose name was redacted by the GSA citing a personal privacy exemption under FOIA, wrote, “Signal sounds great. I don’t want to start a process of getting ‘more secure’ phones for the next 50+ days if we can avoid it and use what we already have.”
It’s unclear whether Flynn, who served as national security adviser for 24 days until he was fired by Trump for lying over his contacts with Russia, actually used the Signal app.
Signal is highly regarded in cyber-security circles because of its sound cryptography and because users can communicate without leaving copies of their messages on any centralized server. Prior to the election, Hillary Clinton’s team reportedly turned to Signal to ensure its communications did not get intercepted by hackers.
Get Data Sheet, Fortune’s technology newsletter.
The use of secure messaging apps—others include by Confide and Wickr—by elected officials and their staffs has been controversial in part because, in some cases, they may violate federal records-keeping laws.
Flynn pled guilty to lying to the FBI in November, and remains a key figure in the ongoing investigation by special prosecutor Robert Mueller into the Trump team’s possible collusion with Russia.