.onion

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.onion
Introduced2004
TLD typePseudo-domain-style host suffix
StatusNot in root, but used by Tor clients, servers, and proxies
RegistryTor
Intended useTo designate a hidden service reachable via Tor
Actual useUsed by Tor users for services in which both provider and user is anonymous and difficult to trace
Registration restrictionsAddresses are "registered" automatically by Tor client when a hidden service is set up
StructureNames are opaque strings such as jv6g2ucbhrjcnwgi.onion, generated from public keys
DocumentsTor design document
Dispute policiesN/A
Registry websitewww.torproject.org

.onion is a pseudo-top-level domain host suffix (similar in concept to such endings as .bitnet and .uucp used in earlier times) designating an anonymous hidden service reachable via the Tor network. Such addresses are not actual DNS names, and the .onion TLD is not in the Internet DNS root, but with the appropriate proxy software installed, Internet programs such as Web browsers can access sites with .onion addresses by sending the request through the network of Tor servers. The purpose of using such a system is to make both the information provider and the person accessing the information more difficult to trace, whether by one another, by an intermediate network host, or by an outsider.

Addresses in the .onion pseudo-TLD are opaque, non-mnemonic, 16-character alpha-semi-numeric hashes which are automatically generated based on a public key when a hidden service is configured. These 16-character hashes can be made up of any letter of the alphabet, and decimal digits beginning with 2 and ending with 7, thus representing an 80-bit number in base 32.

The "onion" name refers to onion routing, the technique used by Tor to achieve a degree of anonymity.

Onion sites

A few examples of .onion hosts are:

WWW to .onion proxies

Proxies into the TOR network allow accessing dynamically routed services from non-TOR browsers.

tor2web

Allows access using a non-TOR browser by changing the domain suffix .onion of any hidden service host to .tor2web.com. The protocol prefix http:// can also be changed into https:// to use an encrypted connection to the tor2web proxy server in order to provide additional privacy.

For example http://axqzzpkfwezf3kku.onion would become https://axqzzpkfwezf3kku.tor2web.com.

Using a proxy server of this kind decreases the level of security in comparison to using Tor by having it installed on the computer.[1]

.exit

.exit is a pseudo-top-level domain used by Tor users to indicate on the fly to the Tor software the preferred exit node that should be used while connecting to a service such as a web server, without having to edit the configuration file for Tor (torrc)

The syntax used with this domain is hostname + .exitnode + .exit, so that a user wanting to connect to www.torproject.org through node tor26 would have to enter the URL www.torproject.org.tor26.exit.

Example uses for this include accessing a site available only to addresses of a certain country or checking if a certain node is working.

Users can also type exitnode.exit alone to access the IP address of exitnode

References

  1. ^ "tor2web.com: visit anonymous websites". Retrieved 2009-09-16.

External links