... What exactly are you worried about? - That someone will sniff your contacts while you send them? I can tell you it's highly unlikely for many reasons. I know the trouble I went through to replicate the request sent to server. - That Whatsapp Inc. will have all your contacts and use the data in some way? Then don't sync ever again, use only pushnames. - Or are you just paranoid and saw a default privacy popup somewhere and now you insist on it? I hope not. ... You are not a VIP or a very appealing target. Nobody wants your data and nobody is interested about your chats or contacts. There are more efficient ways of stealing them or violating your privacy then the basis of XMPP. Please, don't link any blogs here about Whatsapp vulnerability bla bla bla. I've read them all. Yes there are weak points, but to a trained person, it's weak as any other chat protocol with default protection. I'm a beginner and I can easily intrude into many GTalks, XMPPs, Facebook Chats and profiles. ...