In just a day, Swiss messaging startup Threema has increased its user base by twice the original number, according to Suddeutsche. The app is now ranked top in Germany's paid App Store chart. The main reason for this is the Germans' preference for the app's end-to-end encryption feature, according to TechCrunch.

The startup's website says: "Unlike other popular messaging apps (including those claiming to use encryption), even we as the server operator have absolutely no way to read your messages."

WhatsApp, another messaging startup recently acquired by Facebook for $19 billion, also promises high security level. However, it has experienced security glitches before. Facebook is a company that is currently based on advertising, the report explained.

With approximately 30 million users in Germany alone, WhatsApp is clearly the leader in the industry. The massive switch to Threema, which only has three members in its team, comes as a surprise. Out of the 200,000 new Threema users who shelled out $1.99 for its secure messaging service, 80% are from Germany, TechCrunch reported.