The Tor project presents a second-generation onion routing system that improves upon the original design by adding perfect forward secrecy, congestion control, directory servers, integrity checking, configurable exit policies, and a practical design for location-hidden services via rendezvous points. Tor is a circuit-based anonymous communication service that works on the real-world Internet, requires no special privileges or kernel modifications, and provides a reasonable tradeoff between anonymity, usability, and efficiency. It allows users to communicate anonymously while maintaining usability and efficiency. Tor is implemented on a network of more than 30 nodes and has been deployed on a wide-area alpha network with 32 nodes spread over two continents. Tor uses a protocol for asynchronous, loosely federated onion routers that provides several improvements over the old onion routing design. These include perfect forward secrecy, separation of "protocol cleaning" from anonymity, no mixing, padding, or traffic shaping (yet), multiple TCP streams can share one circuit, leaky-pipe circuit topology, congestion control, directory servers, variable exit policies, end-to-end integrity checking, and rendezvous points and hidden services. Unlike Freedom, Tor does not require OS kernel patches or network stack support, which prevents it from anonymizing non-TCP protocols but has greatly helped its portability and deployability. Tor's design is based on a distributed overlay network that allows users to communicate anonymously while maintaining usability and efficiency. It uses a TLS connection between onion routers and users' onion proxies to ensure secure communication. Each onion router maintains a long-term identity key and a short-term onion key, and uses these keys to decrypt requests from users to set up a circuit and negotiate ephemeral keys. The TLS protocol also establishes a short-term link key when communicating between ORs, which are rotated periodically and independently to limit the impact of key compromise. Tor's design includes a leaky-pipe circuit topology that allows traffic to exit the circuit from the middle, which can help frustrate traffic shape and volume attacks based on observing the end of the circuit. It also includes congestion control that allows nodes at the edges of the network to detect congestion or flooding and send less data until the congestion subsides. Tor also includes directory servers that provide signed directories describing known routers and their current state, and variable exit policies that allow each node to advertise a policy describing the hosts and ports to which it will connect. Tor's design also includes end-to-end integrity checking to prevent attacks where any node on the circuit could change the contents of data cells as they pass by. It also includes rendezvous points and hidden services that allow users to communicate anonymously while maintaining usability and efficiency. Tor's design is based on a distributed overlay network that allows users to communicate anonymously while maintaining usability and efficiency. It uses a TLS connection between onion routers and users' onion proxies to ensure secure communication. Each onion router maintains a long-term identity key and a short-term onion key, and uses these keys to decrypt requests from users to set up a circuit and negotiate ephemThe Tor project presents a second-generation onion routing system that improves upon the original design by adding perfect forward secrecy, congestion control, directory servers, integrity checking, configurable exit policies, and a practical design for location-hidden services via rendezvous points. Tor is a circuit-based anonymous communication service that works on the real-world Internet, requires no special privileges or kernel modifications, and provides a reasonable tradeoff between anonymity, usability, and efficiency. It allows users to communicate anonymously while maintaining usability and efficiency. Tor is implemented on a network of more than 30 nodes and has been deployed on a wide-area alpha network with 32 nodes spread over two continents. Tor uses a protocol for asynchronous, loosely federated onion routers that provides several improvements over the old onion routing design. These include perfect forward secrecy, separation of "protocol cleaning" from anonymity, no mixing, padding, or traffic shaping (yet), multiple TCP streams can share one circuit, leaky-pipe circuit topology, congestion control, directory servers, variable exit policies, end-to-end integrity checking, and rendezvous points and hidden services. Unlike Freedom, Tor does not require OS kernel patches or network stack support, which prevents it from anonymizing non-TCP protocols but has greatly helped its portability and deployability. Tor's design is based on a distributed overlay network that allows users to communicate anonymously while maintaining usability and efficiency. It uses a TLS connection between onion routers and users' onion proxies to ensure secure communication. Each onion router maintains a long-term identity key and a short-term onion key, and uses these keys to decrypt requests from users to set up a circuit and negotiate ephemeral keys. The TLS protocol also establishes a short-term link key when communicating between ORs, which are rotated periodically and independently to limit the impact of key compromise. Tor's design includes a leaky-pipe circuit topology that allows traffic to exit the circuit from the middle, which can help frustrate traffic shape and volume attacks based on observing the end of the circuit. It also includes congestion control that allows nodes at the edges of the network to detect congestion or flooding and send less data until the congestion subsides. Tor also includes directory servers that provide signed directories describing known routers and their current state, and variable exit policies that allow each node to advertise a policy describing the hosts and ports to which it will connect. Tor's design also includes end-to-end integrity checking to prevent attacks where any node on the circuit could change the contents of data cells as they pass by. It also includes rendezvous points and hidden services that allow users to communicate anonymously while maintaining usability and efficiency. Tor's design is based on a distributed overlay network that allows users to communicate anonymously while maintaining usability and efficiency. It uses a TLS connection between onion routers and users' onion proxies to ensure secure communication. Each onion router maintains a long-term identity key and a short-term onion key, and uses these keys to decrypt requests from users to set up a circuit and negotiate ephem