Symmetric,orprivate-key,encryptionisbasedonasecretkeythatissharedbybothcommuncatingparties.The(_______)partyusesthesecretkeyaspartofthemathematicaloperationtoencrypt()texttociphertext.Thereceivingpartyusesthesamesecretkeytodecrypttheciphertexttoplaintext.Asymmetric,orpublic-key,encryptionusestwodifferentkeysforeachuser:oneisa()keyknownonlytothisoneuser;theotherisacorrespondingpublickey,whichisaccessibletoanyone.Theprivateandpublickeysaremathematicallyrelatedbytheencryptionalgorithm.Onekeyiausedforencyptionandtheotherfordecryption,dependingonthenatureofthecommunicationservicebeingimplemented.Inaddition,publickeyencryptiontechnoligiesallowdigital()tobeplacedonmessages.Adigitalsignatureusesthesender'sprivatekeytoencryptsomeportionofthemessage.Whenthemessageisreceived,thereceiverusesthesender's()keytpdecipherthedigitalsignaturetoverifythesender'sidentity. 横线处应选()。
A.host B.terminal C.sending D.receiving正确答案C
