tailieunhanh - Internet Security Cryptographic Principles, Algorithms and Protocols - Chapter 9

Electronic Mail Security: PGP, S/MIME Pretty Good Privacy (PGP) được phát minh bởi Philip Zimmermann đã phát hành phiên bản vào năm 1991. Sau đó phiên bản và (hoặc ) của PGP đã được thực hiện bởi một sự hợp tác tất cả các tình nguyện theo hướng dẫn thiết kế của Zimmermann. PGP là sử dụng rộng rãi trong các phiên bản cá nhân và thương mại chạy trên nhiều nền tảng trong cộng đồng máy tính. PGP sử dụng một sự kết hợp của mã hóa đối xứng khóa công khai bí mật quan trọng. | 9 Electronic Mail Security PGP S MIME Pretty Good Privacy PGP was invented by Philip Zimmermann who released version in 1991. Subsequent versions and or of PGP have been implemented by an all-volunteer collaboration under the design guidance of Zimmermann. PGP is widely used in the individual and commercial versions that run on a variety of platforms throughout the computer community. PGP uses a combination of symmetric secret-key and asymmetric public-key encryption to provide security services for electronic mail and data files. It also provides data integrity services for messages and data files by using digital signature encryption compression zip and radix-64 conversion ASCII Armor . With the explosively growing reliance on e-mail and file storage authentication and confidentiality services have become increasing demands. MIME is an extension to the RFC 2822 framework which defines a format for text messages being sent using e-mail. MIME is actually intended to address some of the problems and limitations of the use of SMTP. Secure Multipurpose Internet Mail Extension S MIME is a security enhancement to the MIME Internet e-mail format standard based on technology from RSA Data Security. Although both PGP and S MIME are on an IETF standards track it appears likely that PGP will remain the choice for personnel e-mail security for many users while S MIME will emerge as the industry standard for commercial and organisational use. Two schemes of PGP and S MIME are discussed in this chapter. PGP Before looking at the operation of PGP in detail it is convenient to confirm the notation. In the forthcoming analyses for security and data integrity services the following symbols are generally used Internet Security. Edited by . Rhee 2003 John Wiley Sons Ltd ISBN 0-470-85285-2 306 INTERNET SECURITY Ks session key KPa public key of user A KSa private key of user A E conventional encryption Ep public-key encryption Z compression using zip algorithm