Checking of a bit flow
AssigneeSTMicroelectronics S.r.l.
InventorsPierre-Yvan Liardet, Yannick Teglia
Life of this patent
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Abstract
A method and a circuit for detecting a possible loss of the equiprobable character of a first output bit flow originating from at least one first normalization element of an initial bit flow, consisting of submitting the initial flow to at least one second normalization element of a nature different from the first one, pairing, bit to bit, the flows originating from the two elements, and checking the equidistribution of the different state pairs.
Claims13
A circuit to check a bit flow derived from a noise source, the circuit comprising:
- at least one first normalization circuit to change at least one value of the bit flow provided by the noise source, and to output a first modified output flow;
- at least one second normalization circuit to change at least one value of the bit flow and to output a second modified output flow different from the first modified output flow;
- means for pairing, bit to bit, the first modified output flow and the second modified output flow to provide a plurality of bit pairs, each bit pair formed of one bit of the first modified output flow and one bit of the second modified output flow;
- and
- means for checking an equidistribution of multiple possible states of the plurality of bit pairs, and providing an indication of an equiprobable distribution of the first modified output flow and the second modified output flow based on the equidistribution of the multiple possible states.
A method for detecting a possible loss of an equiprobable character of a first output bit flow, the method comprising:
- submitting an initial bit flow to at least one first normalization circuit that changes at least one value of the initial bit flow to produce the first output bit flow;
- submitting the initial flow to at least one second normalization circuit that changes at least one value of the initial bit flow to produce a second bit flow different from the first output bit flow;
- pairing, bit to bit, the first output bit flow and the second bit flow to provide a plurality of bit pairs, each bit pair formed of one bit of the first output bit flow and one bit of the second bit flow;
- checking an equidistribution of different possible states of the plurality of bit pairs;
- and
- indicating an equiprobable distribution of the first output bit flow and the second bit flow based on the equidistribution of the different possible states.
An apparatus, comprising:
- a first normalization circuit to change at least one value of a bit flow derived from a noise source, the first normalization circuit outputting a first modified output flow;
- a second normalization circuit to change at least one value of the bit flow and to output a second modified output flow different from the first modified output flow;
- and
- a checking circuit coupled to the first normalization circuit and the second normalization circuit to provide an indication of a randomness of at least the first modified output flow.
Dependencies are inferred from the claim text.