网络安全电子邮件安全教学课件PPT汇总.pptVIP

* 西安电子科技大学计算机学院 * S/MIME Certificate Processing S/MIME uses X.509 v3 certificates managed using a hybrid of a strict X.509 CA hierarchy PGP’s web of trust each client has a list of trusted CA’s certs and own public/private key pairs certs certificates must be signed by trusted CA’s * 西安电子科技大学计算机学院 * Certificate Authorities have several well-known CA’s Verisign one of most widely used Verisign issues several types of Digital IDs increasing levels of checks hence trust Class Identity Checks Usage 1 name/email check web browsing/email 2 + enroll/addr check email, subs, s/w validate 3 + ID documents e-banking/service access * 西安电子科技大学计算机学院 * 小 结 Email的安全 PGP S/MIME（略） * 西安电子科技大学计算机学院 * 第15章作业 第1题 * * In virtually all distributed environments, electronic mail is the most heavily used network-based application. But current email services are roughly like postcards”, anyone who wants could pick it up and have a look as its in transit or sitting in the recipients mailbox. * With the explosively growing reliance on electronic mail for every conceivable purpose, there grows a demand for authentication and confidentiality services. What we want is something more akin to standard mail (contents protected inside an envelope) if not registered mail (have confidence about the sender of the mail and its contents). That is, the “classic” security services listed are desired. * The Pretty Good Privacy (PGP) secure email program, is a remarkable phenomenon, has grown explosively and is now widely used. Largely the effort of a single person, Phil Zimmermann, who selected the best available crypto algorithms to use integrated them into a single program, PGP provides a confidentiality and authentication service that can be used for electronic mail and file storage applications. It runs on a wide range of systems, in both free commercial versions. * The actual operation of PGP consists of five services: authentication, confidentiality, compression, e-mail compatibility, and