{HEAD ~ The individual authentication instances} are evaluated based upon: the degree of match between the user provided by the first user during the authentication and the data provided by the first user during his enrollment; the inherent reliability of the authentication technique being used; the circumstances surrounding the generation of the authentication data by the first user; and {TAIL ~ the circumstances} surrounding the generation of the enrollment data by the first user 
are evaluated based upon
{ HEAD ~ The individual authentication instances } are evaluated based upon : the degree of match between the user provided by the first user during the authentication and the data provided by the first user during his enrollment ; the inherent reliability of the authentication technique being used ; the circumstances surrounding the generation of the authentication data by the first user ; and { TAIL ~ the circumstances } surrounding the generation of the enrollment data by the first user
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