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Illustration of "Cryptology"

Cryptology embraces two branche: Cryptanalysis & Cryptography

6 mains concepts of cryptography:

  • Confidentiality/Secrecy: Only the destination can read the message
  • Authentication: The destination can be sure the message is sent by the sender
  • Integrity: The message cannot be changed during the transmission
  • Source nonrepudiation: The source cannot deny sending the message
  • Destination nonrepudiation: The destination cannot deny receiving the message
  • Signatures: Third parties can be sure that the message is sent by the sender
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Illustration of "System security 22 1/2"

ENT test

Find false randomness (not a proof to true randomness)

  • entropy
  • compression
  • chi-square
  • arithmetic mean
  • montecarlo estimation for PI
  • serial correlation coefficient)


Example: Entropy = 7.980627 bits per character.

Optimum compression would reduce the size
of this 51768 character file by 0 percent.

Chi square distribution for 51768 samples is 1542.26, and randomly
would exceed this value less than 0.01 percent of the times.

Arithmetic mean value of data bytes is 125.93 (127.5 = random).
Monte Carlo value for Pi is 3.169834647 (error 0.90 percent).
Serial correlation coefficient is 0.004249 (totally uncorrelated = 0.0).
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12 posts found