Security on The Web Part 2

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Security on The Web Part 2

• Norman White

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Web Security Problems

• Information between server and browser is passed
  unencrypted
• Any listener can see all text, gifs, videos
  etc. as they pass between the client machine and
  the server.
• Problem How do we ensure
• Security
• Authentication

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Current Solution - SSL

• Secure Sockets Layer
• A protocol developed by Netscape for WEB based
  transactions
• Includes
• Authentication
• Stream Encryption
• Block Encryption
• Use both single key and public key encryption
• Has already been broken (several times)

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Cracking SSL

• Hackers cracked SSL by using many computers to
  generate the pseudo random numbers used to do the
  single key encryption
• They took about 8 days to crack one message,
  encrypted with the least secure method.

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Summary

• SSL pretty good, but needs to be fixed up a
  little
• Plenty secure enough for most transactions
• Basic structure seems OK

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Related Topic - Compression

• Two types of compression
• Lossless
• Original content can be reconstructed exactly
• GIF is a lossless technique
• Lossy
• Original content can only approximately be
  reconstructed
• JPG is a lossy method
• Lossy methods can usually compress more than Lossy

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Compressed Multimedia and Encryption

• What happens when we combine compression and
  encryption?
• Several problems
• 1 encrypt then compress
• Encryption will (probably) destroy any patterns
  that could be used to compress
• 2 compress then encrypt
• OK, but cant handle real-time multimedia
• 3 Streaming encryption
• SSL has a simple high performance solution for
  streaming based on single key encryption