[1][2] Secure communication includes means by which people can share information with varying degrees of certainty that third parties cannot intercept what is said.
In 1898, Nikola Tesla demonstrated a radio controlled boat in Madison Square Garden that allowed secure communication between transmitter and receiver.
When this was found to be untrue, engineers started to work on a whole new system, which resulted in the Green Hornet or SIGSALY.
These types of activity are usually addressed with everyday mainstream security methods, such as antivirus software, firewalls, programs that identify or neutralize adware and spyware, and web filtering programs such as Proxomitron and Privoxy which check all web pages being read and identify and remove common nuisances contained.
Provided it is correctly programmed, sufficiently powerful, and the keys not intercepted, encryption would usually be considered secure.
True identity-based networks replace the ability to remain anonymous and are inherently more trustworthy since the identity of the sender and recipient are known.
It is possible for a cellphone company to turn on some cellphones when the user is unaware and use the microphone to listen in on you, and according to James Atkinson, a counter-surveillance specialist cited in the same source, "Security-conscious corporate executives routinely remove the batteries from their cell phones" since many phones' software can be used "as-is", or modified, to enable transmission without user awareness and the user can be located within a small distance using signal triangulation and now using built in GPS features for newer models.
Some cellphones (Apple's iPhone, Google's Android) track and store users' position information, so that movements for months or years can be determined by examining the phone.
Such tapping requires physical access to the line which can be easily obtained from a number of places, e.g. the phone location, distribution points, cabinets and the exchange itself.
Anonymous proxies are another common type of protection, which allow one to access the net via a third party (often in a different country) and make tracing difficult.
Note that there is seldom any guarantee that the plaintext is not tappable, nor that the proxy does not keep its own records of users or entire dialogs.
A recent development on this theme arises when wireless Internet connections ("Wi-Fi") are left in their unsecured state.
[8] Conversely, in other cases, people deliberately seek out businesses and households with unsecured connections, for illicit and anonymous Internet usage, or simply to obtain free bandwidth.
In September 2024 Eurojust, Europol, and law enforcement agencies from a number of countries took down a secure communication service used for organized crime.
The encryption network was operated by equipment and personnel in Sweden, Ireland, the Netherlands, France, Spain, Italy, Australia, and Canada.