To protect every users contact information from third parties and Wickr, the app will send a hashed representation of your friends’ phone number and email address to our servers, at which point our server will check that representation against our database to see if that contact has an associated Wickr ID.
If they have a Wickr ID, then you may send them a Wickr message.
If they don’t then you may send a pre-populated invitation via SMS or email.
All invitations are generated locally on your device, and do not share any information with us.
More info: What is Contact Finder?