IC cards and information storage circuit therefor

Claim 2

An IC card having a self-identification function in the card itself, comprising: an input means for inputting a primary personal identification number and a secondary personal identification number; a storage means for storing a primary reference personal identification number and a secondary reference personal identification number; a primary comparing means for comparing the primary personal identification number input by use of the input means with the primary personal identification number prerecorded in said storage means; a secondary comparing means for comparing the secondary personal identification number input using the input means with the secondary personal identification number prerecorded in said storage means; a personal identification number match memory comprising an electrically erasable programmable read-only memory for storing data indicating that a match has been found by said primary comparing means and for producing a first signal representing said data; a timer circuit triggered into a first state when a match is found by said primary comparing means or by said secondary comparing means, and maintaining said first state for a predetermined interval and producing a second signal while said first state is maintained; external terminals for outputting, to the outside of the IC Card, said signal produced by said personal identification number match memory and said signal produced by said timer circuit; an additional external terminal for receiving a third signal from outside of the IC card, said personal identification number match memory receiving said third signal and said data being erased upon receipt of said third signal.

Claim 3

An IC card according to claim 1, wherein said timer circuit comprises an information storage circuit comprising: an input terminal; a first FET having a gate connected to the input terminal, and having a drain connected to a power supply; a capacitor connected between a source of the first FET and ground; a second FET having a gate connected to the source of the first FET, and having a source which is grounded and having a drain connected to an output terminal; and a means for applying a pulse to the input terminal when a match has been found by said primary comparing means to charge said capacitor; wherein, when a pulse is applied to the input terminal, information is maintained at the output terminal for a predetermined time determined by the capacitance of the capacitor and the leakage current, even if the voltage of the power supply disappears or drops.

Claim 4

An IC card according to claim 2, wherein said means applying a pulse applies a pulse which is greater than the sum of the power supply voltage and the threshold voltage of the first FET.

Claim 5

An IC card according to claim 1, wherein said match memory produces a high level output when a match is found by said primary comparing means.

Claim 6

An IC card according to claim 2, wherein said power supply comprises a solar battery.

Claim 7

An IC card according to claim 3, wherein said means applying a pulse comprises a level shifter responsive to a logic level within the voltage range of the power supply and producing a pulse exceeding the voltage range of the power supply.

Claim 8

An IC card according to claim 1, wherein said storage means comprises a read-only memory.

Claim 9

An IC card according to claim 7, wherein said read-only memory comprises an electrically erasable programmable read-only memory.

Claim 10

A transaction system comprising transaction terminal equipment and an IC card inserted in said transaction terminal equipment when the transaction is made; wherein said IC card comprises: an input means for inputting a primary personal identification number and a secondary personal identification number; a storage means for storing a primary reference personal identification number and a secondary reference personal identification number; a primary comparing means for comparing the primary personal identification number input using the input means with the primary reference personal identification number prerecorded in said storage means; a secondary comparing means for comparing the secondary personal identification number input using the input means with the secondary reference personal identification number prerecorded in said storage means; a personal identification number match memory for storing data indicating that a match has been found by said primary comparing means and for producing a first signal representing said data; and a timer circuit for triggering into a first state when a match is found by said primary comparing means or by secondary comparing means, and for maintaining said first state for a predetermined interval and for producing a second signal while said first state is maintained; and wherein said transaction terminal equipment comprises: a transaction enable/disable section for enabling a transaction when it receives said first and second signals from the IC card; and a means for producing a third signal when the transaction is effected; said data in said personal identification number match memory being erased when said third signal is received.

Claim 11

A transaction system comprising transaction terminal equipment and an IC card inserted in said transaction terminal equipment when the transaction is made; wherein said IC card comprises: an input means for inputting a primary personal identification number and a secondary personal identification number; a storage means for storing a primary reference personal identification number and a secondary reference personal identification number; a primary comparing means for comparing the primary personal identification number input using the input means with the primary reference personal identification number prerecorded in said storage means; a secondary comparing means for comparing the secondary personal identification number input using the input means with the secondary reference personal identification number prerecorded in said storage means; a personal identification number match memory for storing data indicating that a match has been found by said primary comparing means and for producing a first signal representing said data; and a timer circuit for triggering into a first state when a match is found by said primary comparing means or by secondary comparing means, and for maintaining said first state for a predetermined interval and for producing a second signal while said first state is maintained; and wherein said transaction terminal equipment comprises: a transaction enable/disable section for enabling a transaction when it receives said first and second signals from the IC card; and a means for producing a third signal when the transaction is effected; said data in said personal identification number match memory being erased when said third signal is received.

Claim 12

A transaction method using an IC card in combination with transaction terminal equipment, comprising the steps of: inputting, into the IC card, a primary personal identification number; comparing the input primary personal identification number with a primary reference personal identification number stored in the IC card; storing data indicating that said input primary personal identification number and said primary reference personal identification number are found to match; outputting a first signal representing said stored data as long as said data is stored; triggering a timer into a first state when said input primary personal identification number and said primary reference personal identification number are found to match, said timer being kept in said first state for a predetermined period after said triggering; inputting, when said predetermined period has expired after said triggering and said timer is therefore not in said first state, into the IC card, a secondary personal identification number; comparing the input secondary personal identification number with a secondary reference personal identification number stored in the IC card; retriggering, when the input secondary personal identification number and the secondary reference personal identification number are found to match; said timer being kept in said first state for said predetermined period after said retriggering; outputting a second signal as long as said timer is in said first state; transmitting said first and second signals when said IC card is inserted into said transaction terminal equipment; permitting a transaction using the transaction terminal equipment when said IC card is inserted into said transaction terminal equipment and both said first signal and said second signal are active; transmitting a third signal when the transaction is effected; and erasing said data upon receipt of said third signal.

Claim 13

A transaction method using an IC card in combination with transaction terminal equipment, comprising the steps of: inputting, into the IC card, a primary personal identification number; comparing the input primary personal identification number with a primary reference personal identification number stored in the IC card; storing data indicating that said input primary personal identification number and said primary reference personal identification number are found to match; outputting a first signal representing said stored data as long as said data is stored; triggering a timer into a first state when said input primary personal identification number and said primary reference personal identification number are found to match, said timer being kept in said first state for a predetermined period after said triggering; inputting, when said predetermined period has expired after said triggering and said timer is therefore not in said first state, into the IC card, a secondary personal identification number; comparing the input secondary personal identification number with a secondary reference personal identification number stored in the IC card; retriggering, when the input secondary personal identification number and the secondary reference personal identification number are found to match; said timer being kept in said first state for said predetermined period after said retriggering; outputting a second signal as long as said timer is in said first state; transmitting said first and second signals when said IC card is inserted into said transaction terminal equipment; permitting a transaction using the transaction terminal equipment when said IC card is inserted into said transaction terminal equipment and both said first signal and said second signal are active; transmitting a third signal when the transaction is effected; and erasing said data upon receipt of said third signal.