Feedback shift register control
AssigneeInfineon Technologies AG
InventorsRainer Goettfert, Stefan Rueping
Life of this patent
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Abstract
Feedback shift register control circuit including a checking circuit having an input being coupled to a seed input of a feedback shift register or to an internal node of the feedback shift register, the checking circuit configured to be responsive to a signal at the input indicating that the feedback shift register is in a not-allowed state, or is going to assume a not-allowed state to output an exception signal; and a gate circuit being coupled to the seed input or the feedback shift register and configured to be responsive to the exception signal to change the state of the feedback shift register or seed the feedback shift register such that the feedback shift register assumes an allowed state.
Claims25
A feedback shift register control circuit, comprising:
- a checking circuit having an input being coupled to a seed input of a feedback shift register or to an internal node of the feedback shift register, the checking circuit configured to be responsive to a signal at the input indicating that the feedback shift register is in a not-allowed state or is going to assume a not-allowed state, to output an exception signal;
- and
- a gate circuit being coupled to the seed input or the feedback shift register and configured to be responsive to the exception signal to change the state of the feedback shift register or seed the feedback shift register such that the feedback shift register assumes an allowed state.
An apparatus controlling a feedback shift register, comprising:
- means for checking one of whether the feedback shift register is in a not-allowed state or whether the feedback shift register is seeded such that the feedback shift register is going to assume the not-allowed state;
- and
- means for, upon the one of the feedback shift register being in the not-allowed state, or the feedback shift register being seeded such that the feedback shift register is going to assume the not-allowed state, changing the state of the feedback shift register or seeding the feedback shift register such that the feedback shift register assumes an allowed state.
A method for controlling a feedback shift register, comprising:
- checking one of whether the feedback shift register is in a not-allowed state or whether the feedback shift register is seeded such that the feedback shift register is going to assume the not-allowed state;
- and
- upon the one of the feedback shift register being in the not-allowed state, or the feedback shift register being seeded such that the feedback shift register is going to assume the not-allowed state, changing the state of the feedback shift register or seeding the feedback shift register such that the feedback shift register assumes an allowed state.
A circuit comprising:
- a feedback shift register coupled to an output of a true random number generator and having a feedback function defining a fixed state among possible internal states of the feedback shift register;
- and
- a control circuit being responsive to the fixed state to influence the internal state of the feedback shift register.
A computer readable medium having a computer program instruction recorded thereon for performing, when running on a computer, a method for controlling a feedback shift register, comprising:
- checking one of whether the feedback shift register is in a not-allowed state or whether the feedback shift register is seeded such that the feedback shift register is going to assume the not-allowed state;
- and
- upon the one of the feedback shift register being in the not-allowed state, or the feedback shift register being seeded such that the feedback shift register is going to assume the not-allowed state, changing the state of the feedback shift register or seeding the feedback shift register such that the feedback shift register assumes an allowed state.
Dependencies are inferred from the claim text.