Moxie (https://en.wikipedia.org/wiki/Moxie_Marlinspike) updated TextSecure Server so that we could create TextSecure clients on the Pipem platform.
Now Pipem users can securely send commands to Uber and other online services using:
Secure Text: TextSecure (Android) / Signal (iOS), or the default messenger in CyanogenMod (CM now uses the TextSecure protocol for its default messenger).
Email: Must use a secure, authenticated email account that supports DMARC (e.g. Gmail).
Voice: Use Google Now on your Android phone / Android Wear device / Chrome plugin. Use Siri on iOS iPhone / iPad / Apple Watch.
WhatsApp on Android (experimental): The latest version of WhatsApp on Android uses the TextSecure protocol under the hood (http://www.wired.com/2014/11/whatsapp-encrypted-messaging/ , https://whispersystems.org/blog/whatsapp/) so you should be able to send Pipem commands via WhatsApp now that it uses the TextSecure protocol to provide end-to-end encryption.