Well, if you are all using the same network, he can probably sniff your packets, which means that he/she can see all the traffic coming from and going towards your computer (your wireless card to be more precise). This is pretty much unavoidable.
What you can do, is to visit https version of sites, since then he/she can only see what site are you visiting, but not what data are you transmitting (password, chats, etc.). Generally speaking, you should always use https to connect to sites.
Also, if you want to be on the safe side, you could always pay for some personal VPN, which will encrypt ALL traffic to and from your computer, and they are fairly cheap. You can find many under 10$ a month, and they do provide very good encryption.
However, if you are concerned about traffic usage, there is no way to hide it, because even if he cannot "see" what you are doing, he can measure it. That means if you download 20 gigabytes of data, he will sure be able to measure how much did you download.
Measuring the downloaded amount is something that does not require advanced knowledge to get to work. Most routers these days can display traffic amount for each ip address associated to it, directly in their configuration/status panel, which the owner of the router probably has access to.
On the other hand, sniffing the data and getting your passwords, chats. etc does require that you visit non-encrypted site, but also requires some level of technical knowledge. Although with youtube tutorials around, I wouldn't put it past anyone. That is why visiting https version of sites is highly recommended (if not a must). Also, personal vpn is good investment if you are using untrusted hotspots (public for example, or even the one you are renting now).
The thing is yesterday my friend came to my house and download adult stuff and i was wondering whether if they can see this or not. I am using safari and i do not know how to put Https – Matrix – 2014-04-17T11:46:00.997
Well, with facebook for example, you can visit it using http://facebook.com and also https://facebook.com. The second one (https) is more secure and encrypted and they cannot see WHAT you are doing on facebook, but they can see that you are on facebook. So, if the adult content has address of www.adultcontent.com they will be able to see what you are visiting even if you use https. However, it is worth noting that unless they have installed loging facilities, they cannot see what you did yesterday, unless they were "sniffing" at the exact moment when your friend was viewing the sites.
– dkasipovic – 2014-04-17T11:49:43.133Many...THANKS :) . So that mean they can not view what my friend have been downloading yesterday without loging facilities. How do they even check how much data i have been using and my history. I try going to the IP address but it does not work.. the page does not load. Also can i put Https to this website?? – Matrix – 2014-04-17T11:55:08.557
https:// you can try, it really depends if the site supports https. As for the measuring, the router does that, mostly. Some routers don't. It really depends on the router. – dkasipovic – 2014-04-17T11:57:54.370
How do they check how much data i have been using and my history. I try going to the IP address but it does not work.. the page does not load.. If i can get into it can i check what other have been doing? How can i get into it if there is a way? – Matrix – 2014-04-17T12:11:01.403
What IP address? Measuring does not mean that you can see "what" have they been doing, only "how much" (for example, you downloaded 20 gigabyte of data, they see 20 gigabyte, but not what kind of data, they don't know if you downloaded 20 gigabyte of photos from the internet, or you just watched youtube whole day). – dkasipovic – 2014-04-17T12:13:25.760
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There's a browser extension called https everywhere that forces sites to use https - https://www.eff.org/https-everywhere
– stib – 2014-04-17T12:17:43.850Are you talking about the ip address of the router? Is it something like 192.168.0.1? – stib – 2014-04-17T12:18:38.640
I only tried to explain the approaches that might be used to monitor ones wifi network. I do not want to go into how user can enter into router configuration panel, etc. That is totally another topic, and largely depends on the router. – dkasipovic – 2014-04-17T12:20:11.960
yes i was talking about the ip address 192.168.0.8 and how the user can see what i have been doing and ways to go into it if possible. Thanks for website but there no one for safari :( – Matrix – 2014-04-17T12:23:16.267