Pretty Good Privacy

Please use the reference material indicated to answer the four questions below. Email me your answers to these questions prior to our class meeting on Monday, April 23rd.

  1. How is public-key cryptography used in practice? Why is private-key cryptography inadequate/inconvenient by itself?
    [Textbook, page 908, and PGP, page 6.]

  2. Describe the process by which a sender digitally signs a message. What two things does a digital signature prove to the recipient?
    [Textbook, pages 910, and PGP, pp.24-25 ("Message Digests and Digital Signatures").]

  3. Describe the "disaster" that can be created by public-key tampering.
    [PGP, Page 14 ("How to Protect Public Keys from Tampering").]

  4. How is the vulnerability caused by public-key tampering addressed?
    [Textbook, pages 911-912, and PGP, pages 14-15.]