law: Information Technology Act, 2000
  42. Control of private key. – 
  (1) Every subscriber shall exercise reasonable
  
  care to retain control of the private key corresponding to the public key
  
  listed in his Digital Signature Certificate and take all steps to prevent its
  
  disclosure to a person not authorized to affix the digital signature of the subscriber.
  
  
  If the private key corresponding to the public
  
  key listed in the Digital Signature Certificate has been compromised, then, the
  
  subscriber shall communicate the same without any delay to the Certifying
  
  Authority in such manner as may be specified by the regulations.
  Explanation:-  For removal of doubts,
  
  it is hereby declared that the subscriber shall be liable till he has informed
  
  the certifying Authority that the private key has been compromised.