TOR allows reducing the risks of both simple and sophisticated traffic analysis by distributing user transactions over several servers on the Internet, so no single point can link user to his destination. Figure : How TOR - Step 1 [22] The idea is comparable to using a twisty, hard-to-follow path in order to get away from somebody who is following you — and then regularly removing your footprints. Instead of taking a direct route from source to destination, data packets on the TOR network take a random path across several relays that hide user’s tracks so no observer at any single point can tell where the data came from or where it's going [22]. User's software or client incrementally forms a circuit of encrypted connections through relays on the network, to create a private network pathway with TOR. The circuit is extended one hop at a time, and each relay along the way recognizes only which relay gave it data and which relay it is giving data to. No specific relay ever knows the whole path that a data packet has taken. The client negotiates a separate set of encryption keys for each hop along the circuit to ensure that each hop can't trace these connections as they pass through [22]. To avoid statistical profiling attacks, the default TOR client restricts its choice of entry nodes to a persistent list of three randomly chosen nodes named “entry guards”. For the middle node, the TOR client sorts TOR relays based on their access link bandwidth and randomly select a relay,
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