Consideration for affects of an xor in a random number generator using ring oscillators

Ryoichi Sato, Yuta Kodera, Md Arshad Ali, Takuya Kusaka, Yasuyuki Nogami, Robert H. Morelos-Zaragoza

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


A cloud service to offer entropy has been paid much attention to. As one of the entropy sources, a physical random number generator is used as a true random number generator, relying on its irreproducibility. This paper focuses on a physical random number generator using a field-programmable gate array as an entropy source by employing ring oscillator circuits as a representative true random number generator. This paper investigates the effects of an XOR gate in the oscillation circuit by observing the output signal period. It aims to reveal the relationship between inputs and the output through the XOR gate in the target generator. The authors conduct two experiments to consider the relevance. It is confirmed that combining two ring oscillators with an XOR gate increases the complexity of the output cycle. In addition, verification using state transitions showed that the probability of the state transitions was evenly distributed by increasing the number of ring oscillator circuits.

Original languageEnglish
Article number1168
Issue number9
Publication statusPublished - Sept 2021


  • Entropy
  • Field programmable gate array
  • Period
  • Ring oscillator
  • State transition
  • Stomatic process
  • True random number generator
  • XOR gate

ASJC Scopus subject areas

  • Information Systems
  • Mathematical Physics
  • Physics and Astronomy (miscellaneous)
  • Electrical and Electronic Engineering


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