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pgp s mime


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Cryptography and network Security
network security, william stallings

Published in: Engineering
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pgp s mime

  1. 1. Pretty Good Privacy
  2. 2. What is PGP? • Open source software package • Provide e-mail security Authentication Confidentiality Compression E-mail Compatibility Segmentation & Reassembly Digital Signature Symmetric Block Encryption ZIP Algorithm Radix-64 To accommodate long e-mail
  3. 3. PGP is widely used • Its available free worldwide • It is based on algorithms that have survived extensive public review and are considered extremely secure Public Key Encryption: RSA, DSS, Diffie-Hellman Symmetric Encryption: CAST-128, IDEA, 3DES Hashing: SHA-1 • It has wide range of applicability • It was not developed by, nor it is controlled by, any governmental or standards organization. • PGP is now on an Internet Standard Track(RFC 3156)
  4. 4. PGP Authentication
  5. 5. PGP Confidentiality
  6. 6. PGP Confidentiality & Authentication
  7. 7. PGP General Format
  8. 8. S/MIME
  9. 9. What is S/MIME? S/MIME (Secure/Multipurpose Internet Mail Extension) is a security enhancement to the MIME Internet e-mail format standard. S/MIME provides… Authentication. Message Integrity. By using digital signing Non-repudiation of origin. Privacy and data security. By using encryption
  10. 10. MIME Header Fields MIME Version Content Type Content transfer encoding Content ID Content Description
  11. 11. S/MIME Types Type Subtype Description Text Plain Enriched Unformatted text (ASCII or ISO 8859). Provides greater format flexibility. Multipart Mixed Parallel Alternative Digest The different parts are independent but are to be transmitted together. Should be presented to the receiver in their original order. Differs from mixed only in that no order is defined. The different parts are alternative versions of the same information. Similar to Mixed but the default type/subtype of each part is message/rfc822. Message rfc822 Partial External body The body is itself an encapsulated message that conforms to RFC822. Used to allow fragmentation in a transparent way to the recipient. Contains a pointer to an object exists else where.
  12. 12. S/MIME Types Type Subtype Description Image Jpeg gif The image is in JPEG format. The image is in GIF format. Video Mpeg MPEG format. Audio Basic Single-channel 8-bit ISDN mu-law encoding at a sample rate of 8kHz Application Postscript Octet-stream Adobe Postscirpt. General binary data consisting of 8-bit bytes.
  13. 13. S/MIME Functions Enveloped Data Signed Data Clear Signe Data Signed and Enveloped Data