Data privacy is the security service that allows an individual to maintain the right to control what information about him is collected, how it is used and who uses it.
In an open network such as the Internet, the increased ability to share information can lead to new ways in which privacy can be breached; new technologies can create new ways to gather information, which may have some negative implications for retaining privacy. The use of data mining and the advent of various search engines has created a capability for data about individuals to be collected and combined from a wide variety of sources very easily.
There is so much information stored in many databases worldwide that an individual has no practical means of knowing of or controlling all of the information about themselves that others may have hold or access. Such information could potentially be sold to others for profit and/or be used for purposes not known to or sanctioned by the individual concerned. The concept of information privacy has become more significant as more systems controlling more information appear.
On the Internet, privacy, a major concern of users, can be divided into these concerns:
Moreover, as location tracking capabilities of mobile devices are increasing, problems related to user privacy arise, since user's position and preferences constitute personal information and improper use of them violates user's privacy.
There are many ways to protect the user’s privacy on the Internet. For example, e-mails can be encrypted and browsing of webpages, as well as other online activities, should be done traceless via anonymizers, so called mix nets. These mix nets can be used to prevent the Internet service providers from knowing which sites one visits and with whom one communicates.