Crowds is an idea from Michael Reiter and Avi Rubin at AT&T. The basic idea is to become anonymous by joining a large and geographically diverse group (crowd), and to pass browsing requests to a random member of your crowd. In effect, every member of the crowd runs a proxy server for the benefit of the eveyone else. Web servers are unable to learn the true source of a request because it is equally likely to have originated from any member of the crowd, and even collaborating crowd members cannot distinguish the originator of a request from a member who is merely forwarding the request on behalf of another.

Crowds seems to have been replaced by a a second generation project called Tor.

Tor is free software and an open network that protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, and it prevents the sites you visit from learning your physical location. Tor works with many of your existing applications, including web browsers, instant messaging clients, remote login, and other applications based on the TCP protocol.

Tor employs cryptography in a multi-layered manner (hence the onion routing analogy), ensuring perfect forward secrecy between routers. A user of the Tor network runs a proxy server on his computer. Internet-facing software can then access Tor through a SOCKS interface. Once inside a Tor network, the traffic is sent from router to router, the Tor software periodically negotiating a virtual circuit through the Tor network, ultimately reaching an exit node at which point the cleartext packet is forwarded on to its original destination. Viewed from the destination, the traffic appears to originate at the Tor exit node. More information can be found on it’s website torproject.org.

Tor doesn’t magically encrypt all of your Internet activities, though.

Virtual Private Networking (VPN) implements private networks over public infrastructure. VPN’s are used by business for legitimate reasons all the time. It has attracted the attention of many organizations looking to both expand their networking capabilities and reduce their costs.

A Virtual Private Network uses tunneling technology to establish private connections through public networks like the Internet. The private nature of a VPN means that the data travelling over the VPN is not generally visible to, or is encapsulated from, the underlying network traffic. This is done with strong encryption, as VPN’s are commonly deployed to be high-security “network tunnels”.

An Internet VPN solution uses a client/server design works as follows:

  1. A remote host (client) wanting to log into the company network first connects to any public Internet Service Provider (ISP).
  2. Next, the host initiates a VPN connection to the company VPN server. This connection is made via a VPN client installed on the remote host.
  3. Once the connection has been established, the remote client can communicate with the internal company systems over the Internet just as if it were a local host.

VPN clients communicate with VPN servers utilizing a number of specialized protocols.

The industry group ‘Virtual Private Networking Consortium’ have defined two types of VPN classifications, Secure VPNs and Trusted VPNs. Trusted VPNs differ from secure VPNs in that they do not provide security features such as data confidentiality through encryption. Secure VPNs however do not offer the level of control of the data flows that a trusted VPN can provide such as bandwidth guarantees or routing.

Anonymous surfing allows you to surf the web without leaving a trail of particulars about your browser, your computer system, your country, IP address, list of fonts installed on your computer etc. This is usually done by entering the address (URL) of the site you wish to go to at the proxy the free anonymous surfing proxy site, and that site will retrieve the page for you and present it to you. The site you visit will not receive any particulars about your system or your IP address because the proxy will not have transmitted such particulars to it.

If you are particularly concerned about privacy and anonymity while surfing, you should note that, when using most of the free anonymous surfing facilities, the URLs you visit are easily gleaned by others. If absolute privacy is your concern, you’d better take a look at commercial solutions which will encrypt all your traffic (including your URLs) in a Virtual Private Network (VPN) giving you privacy from people snooping your connection when you’re connected via wireless broadband, and even privacy from your ISP. Some of these commercial solutions may provide other benefits as well, such as encrypting your email, internet messaging (IM) and chats, etc.