Random number generator with ring oscillation circuit
First Claim
1. A random number generator comprising:
- a plurality of delay circuits connected in a loop;
a pulse generation circuit generating in said loop a pulse signal having a pulse of a width shorter than a total delay time of said plurality of delay circuits; and
a counter connected to an output node of a delay circuit of said plurality of delay circuits to count how many times said pulse signal passes through said output node, and output a true random number data signal based on a value counted by said counter.
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Abstract
A random number generator includes a ring oscillator having an EX-OR gate and four inverters together forming a loop. This loop enters stable state for a start signal having the low level and oscillates for the start signal having the high level. When the start signal has a pulse of a width shorter than the loop'"'"'s delay time, output nodes responsively, sequentially enter metastable state hovering between the high and low levels. The metastable waveform becomes smaller with time and finally disappears. As metastable state cannot be controlled in longevity, it disappears at any random number node. A counter thus outputs a signal serving as true random number data depending on the longevity of the metastable state. A random number generator miniaturized and having reduced power consumption, and of high performance can thus be implemented.
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Citations
19 Claims
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1. A random number generator comprising:
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a plurality of delay circuits connected in a loop; a pulse generation circuit generating in said loop a pulse signal having a pulse of a width shorter than a total delay time of said plurality of delay circuits; and a counter connected to an output node of a delay circuit of said plurality of delay circuits to count how many times said pulse signal passes through said output node, and output a true random number data signal based on a value counted by said counter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification