Former Narcotics Control Bureau (NCB) zonal director Sameer Wankhede is trying to show the alleged messages exchanged with film superstar Shah Rukh Khan as certificate of integrity, the Central Bureau of Investigation (CBI) told the Bombay high court on Monday during a hearing of a petition of the official who is accused of seeking Rs 25 crore as bribe from the actor for not implicating his son Aryan in the Cordelia cruise 'drug bust' case.