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Being on vacation for a few weeks, I only have access to public WiFi.

After I have done some research on google and using the search button here (because "how safe is public WiFi" is a really common question), there's one question I have left: Since encryption seems to make my logins and my WhatsApp messages safe, I wondered if this is true for contacts too?

Is it possible that my number or the number of my phone contacts is exposed? I have disabled any app to have access to those except WhatsApp, phone, messages and Google services.

While the content of the messages may be encrypted - is the contact information like a phone number encrypted, too? Or is it more like that I am spreading the numbers of my friends and family through public WiFi, while no one can read the messages?

schroeder
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FootballisNice
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  • Possible duplicate of [How to check if a Wi-Fi network is safe to connect to?](https://security.stackexchange.com/questions/189021/how-to-check-if-a-wi-fi-network-is-safe-to-connect-to) – DotNetRussell Jul 10 '18 at 13:02
  • I have pointed out the difference at the end of the question @AnthonyRussell – FootballisNice Jul 10 '18 at 13:08
  • The contact info will be encrypted in the communication channel (SSL/TLS), if nothing else. Is that sufficient for your threat scenario? – schroeder Jul 10 '18 at 15:03

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When you're on public Wi-Fi, anything your smartphone transmits unencrypted, including contacts, can be intercepted and read by anyone within radio range.

The question is, then, does your smartphone transmit contacts? Many apps do, but they will mostly use an HTTPS connection to their backend which encrypts the information.

So I think you'll be safe if you stick to well-known apps. The only way to be sure, however, is to use a tool like Wireshark to inspect the traffic your phone sends over the network.

Jaap Joris Vens
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