Wikipedia
Sicher
Sicher (German language word meaning "safe", "secure" or "certain") is a freeware instant messaging application for iOS, Android, and Windows Phone. Sicher allows users to exchange end-to-end encrypted text messages, media files and documents in both private and group chats. Sicher is developed by SHAPE GmbH, German company which pioneered mobile messaging with IM+ multi-messenger app it has been offering since 2002.