Certificatesare()documentsattestingtothe()ofapublickeytoanindividualorotherentity.Theyallowverificationoftheclaimthatagivenpublickeydoesinfactbelongtoagivenindividual.Certificateshelppreventsomeonefromusingaphonykeyto()someoneelse.Intheirsimplestform,Certificatescontainapublickeyandaname.Ascommonlyused,aCertificatealsocontainsan()date,thenameoftheCAthatissuedtheCertificate,aserialnumber,andperhapsotherinformation.Mostimportantly,itcontainsthedigital(请作答此空)ofthecertificateissuer.ThemostwidelyacceptedformatforcertificatesisX.509,thus,CertificatescanbereadorwrittenbyanyapplicationcomplyingwithX.509.
A.signature] B.mark C.stamp D.hypertext正确答案A
