signaturef(Data that binds a sender's identity to the information being sent. A digital signature may be bundled with any message, file, or other digitally encoded information, or transmitted separately. Digital signatures are used in public key environments and provide authentication and integrity services)
signaturef(used to identify the sender of an e-mail message or Usenet article, that appears at the end of either communication); empreintef(used to identify the sender of an e-mail message or Usenet article, that appears at the end of either communication)
