Semiconductor integrated circuit and data carrier with said integrated circuit
AssigneeMatsushita Elec. Ind. Co. Ltd.
InventorsGeorge Nakane, Mitsuyoshi Ohya
Life of this patent
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Abstract
The present invention provides a smaller non-contact IC card that includes a counter for measuring time from when the non-contact IC card enters communication coverage of a reader/writer until it actually receives a command from the reader/writer. By using the time measured by the counter as a random-number value, a high-speed, aperiodic, equally random and hard-to-predict random-number data can be generated, thus achieving minimization of non-contact IC cards.
Claims13
A semiconductor integrated circuit to be used in a data carrier recognizing a signal sent from a reader/writer and responding by returning a signal to the reader/writer in a non-contact information system, wherein
- the semiconductor integrated circuit comprises:
- a rectifier circuit receiving and rectifying carrier transmitted from the reader/writer;
- a demodulator circuit demodulating inputted received signals to reproduce data;
- and
- a random-number generator circuit counting a clock signal from a time when an output voltage from the rectifier circuit exceeds a predetermined value until the reader/writer is recognized to measure a time period and generate random numbers.
A semiconductor integrated circuit to be used in a data carrier recognizing a signal sent from a reader/writer and responding by returning a signal to the reader/writer in a non-contact information system, wherein
- the semiconductor integrated circuit comprises:
- a rectifier circuit receiving and rectifying carrier transmitted from the reader/writer;
- a demodulator circuit demodulating inputted received signals to reproduce data;
- a first random-number generator circuit measuring a time period from a time when an output voltage from the rectifier circuit exceeds a first predetermined value until the reader/writer is recognized to generate random numbers;
- and
- a second random-number generator circuit measuring a time period from a time when the output voltage from the rectifier circuit exceeds a second predetermined value until the reader/writer is recognized to generate random numbers.
A semiconductor integrated circuit to be used in a data carrier recognizing a signal sent from a reader/writer and responding by returning a signal to the reader/writer in a non-contact information system, wherein
- the semiconductor integrated circuit comprises:
- a rectifier circuit receiving and rectifying carrier transmitted from the reader/writer;
- a demodulator circuit demodulating inputted received signals to reproduce data;
- a first random-number generator circuit counting a first clock signal from a time when an output voltage from the rectifier circuit exceeds a predetermined values until the reader/writer is recognized to measure a time period and generate random numbers;
- and
- a second random-number generator circuit counting a second clock signal different from the first clock signals from a time when the output voltage from the rectifier circuit exceeds a predetermined value until the reader/writer is recognized to measure a time period and generate random numbers.
Dependencies are inferred from the claim text.