18 posts found

Illustration of "Data security"


Security is Confidentiality, Integrity, Availability, Authentication, Nonrepudiation.

The assets must be protected (Physical support, Files, Software). Furthermore, network must be secured too because the data must be protected during the transmission itself.

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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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18 posts found