Burp Suite Sequencer performs a number of different mathematical evaluations against a sample of pseudorandom numbers in an attempt to determine the quality of the sources of entropy from when they were generated. Live capture can be used to generate sample values by issuing crafted requests that will result in new values being assigned. This is often done by removing an existing cookie value from a request so that the response provides a new session token in the form of a new Set-Cookie response header.