Signal App is a tightly encrypted chat app - uses Open Whisper for privacy. More secure than Telegram, Whats App, Messenger, etc. Prior co-founder of Whats App left for new pasture at Signal. He injected 50 million into it to grow it, and is acting chair. This might be retaliatory, OR it might be betrayal of the technology. The fact it is down, indicates massive Denial of Service Attack (likely)