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Electronic mail security

It is availiable free on a variety of platforms. Based on well known algorithms. Wide range of applicability Not developed or controlled by governmental or standards organizations | Chapter 5 Electronic mail security Henric Johnson Blekinge Institute of Technology, Sweden http://www.its.bth.se/staff/hjo/ Henric.Johnson@bth.se Henric Johnson Outline Pretty good privacy S/MIME Recommended web sites Henric Johnson Pretty Good Privacy Philip R. Zimmerman is the creator of PGP. PGP provides a confidentiality and authentication service that can be used for electronic mail and file storage applications. Henric Johnson Why Is PGP Popular? It is availiable free on a variety of platforms. Based on well known algorithms. Wide range of applicability Not developed or controlled by governmental or standards organizations Henric Johnson Operational Description Consist of five services: Authentication Confidentiality Compression E-mail compatibility Segmentation Henric Johnson Henric Johnson Compression PGP compresses the message after applying the signature but before encryption The placement of the compression algorithm is critical. The compression . | Chapter 5 Electronic mail security Henric Johnson Blekinge Institute of Technology, Sweden http://www.its.bth.se/staff/hjo/ Henric.Johnson@bth.se Henric Johnson Outline Pretty good privacy S/MIME Recommended web sites Henric Johnson Pretty Good Privacy Philip R. Zimmerman is the creator of PGP. PGP provides a confidentiality and authentication service that can be used for electronic mail and file storage applications. Henric Johnson Why Is PGP Popular? It is availiable free on a variety of platforms. Based on well known algorithms. Wide range of applicability Not developed or controlled by governmental or standards organizations Henric Johnson Operational Description Consist of five services: Authentication Confidentiality Compression E-mail compatibility Segmentation Henric Johnson Henric Johnson Compression PGP compresses the message after applying the signature but before encryption The placement of the compression algorithm is critical. The compression algorithm used is ZIP (described in appendix 5A) Henric Johnson E-mail Compatibility The scheme used is radix-64 conversion (see appendix 5B). The use of radix-64 expands the message by 33%. Henric Johnson Segmentation and Reassembly Often restricted to a maximum message length of 50,000 octets. Longer messages must be broken up into segments. PGP automatically subdivides a message that is to large. The receiver strip of all e-mail headers and reassemble the block. Henric Johnson Sumary of PGP Services Henric Johnson Henric Johnson Format of PGP Message Henric Johnson Henric Johnson Henric Johnson Henric Johnson The Use of Trust Key legitimacy field Signature trust field Owner trust field See Table 5.2 (W. Stallings) Henric Johnson Henric Johnson Revoking Public Keys The owner issue a key revocation certificate. Normal signature certificate with a revote indicator. Corresponding private key is used to sign the certificate. Henric Johnson .