RANDOMNESS MONITOR

• US 3,582,882 A
• Filed: 09/12/1968
• Issued: 06/01/1971
• Est. Priority Date: 09/12/1968
• Status: Expired due to Term

• Current Assignee: George E. Titcomb, John M. Hovey
• Original Assignee: George E. Titcomb, John M. Hovey
• Inventors: Titcomb, George E., Hovey, John M.
• Application Number:
  US04/759,293
• Time in Patent Office: 992 Days
• US Class Current: 340/146.2
• CPC Class Codes: G06F 7/58 Random or pseudo-random number generators
• CPC Class Codes: H04L 2209/26 Testing cryptographic entity, e.g. testing integrity of encryption key or encryption algorithm
• CPC Class Codes: H04L 9/0662 with particular pseudorandom sequence generator

Abstract

A randomness monitor designed to check when the duty cycle of a train of pulses is other than 50 percent; and to check the frequency with which a predetermined combination of digits occurs in the pulse train wherein each of the two above-mentioned function checkers includes a gating circuit, two integrators, voltage comparator and an indicator.

Claims

1. A system for checking the randomness of a generator whose output is a series of one and other conditions, corresponding to two distinct voltage levels, comprising:

first means coupled to the output of said generator for generating a first output pRoportional to the average value of said one condition, second means coupled to the output of said generator for producing a signal corresponding to said other condition upon each occurrence of said one condition, third means coupled to the output of said second means for generating a second output proportional to the average value of said signal, and comparison means coupled to the outputs of said first and third means for generating a second signal proportional to the difference between said first and second outputs.

2. A system for checking the randomness of a generator whose output is a series of first and second conditions, corresponding to two voltage levels, comprising:

gate means coupled to said generator for providing a first output upon the occurrence of one of said conditions, inverting means connected to said gating means for producing a second output corresponding to said other condition on each occurrence of a said first output, integrator means coupled to said gating means and said inverting means for generating two separate signals proportional to the average value of each of said outputs, comparison means coupled to said integrator means for producing a signal proportional to the difference between said outputs, and indicator means coupled to said comparison means responsive to said signals whereby deviation from randomness is measured.

3. The system as in claim 1 further including, a feedback loop coupling the output of said comparison means to said generator for controlling the randomness of the generator output in response to the output of said comparison means.

4. A system for monitoring the randomness of a generator with an output train of binary digits comprising:

means coupled to said generator for generating a first output when the duty cycle of the output train of said generator is other than 50 percent, indicator means responsive to said first output, gating means coupled to the output of said generator for producing a second output at each occurrence of a preselected combination of digits from said generator, sensing circuit means coupled to said gating means for generating a third output when said combination is present more or less often than required for randomness, said sensing circuit means comprising, means coupled to the output of said gating means for generating a third output proportional to the average value of the output from said gating means, means for generating a fourth output proportional to the average value of said second output when said generator output is random, and comparator means coupled to said third and fourth outputs for producing a signal proportional to the difference between said third and fourth outputs.

5. The system as recited in claim 1 further including, gating means coupled to the output of said generator for producing a third output at each occurrence of a preselected combination of digits from said generator, and sensing circuit means coupled to the output of said gating means for generating a third signal when said third output occurs more or less frequently than required for randomness.

6. The system as recited in claim 5 wherein said sensing circuit means comprises, fourth means coupled to the output of said gating means for generating a fourth output proportional to the average value of the output from said gating means, fifth means for generating a fifth output proportional to said fourth output when said bit generator is random, and comparator means coupled to said fourth and fifth outputs for producing a signal proportional to the difference between said fourth and fifth outputs.