JPH0528050A - Method and circuit for copy protection of memory ic card - Google Patents

Abstract

PURPOSE:To prevent important program data or the like in a card from being used without permission. CONSTITUTION:A memory IC card 20 which incorporates a storage circuit 1 and can be read out from the external has the memory address space divided into several segments, and one key information for each segment is provided in this card, and a comparator which compares key information with key information given from the external and a means 3 are provided, and this means 3 validates the read result, of the memory IC card 20 only when all of key information corresponding to respective segments are correct.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a business card memory IC.
The present invention relates to a card copy protection method and circuit.

[0002]

2. Description of the Related Art Conventional memory-IC cards can be easily read and read by a read / write device such as a ROM writer.

[0003]

The above-mentioned conventional memory-IC card can be read by a ROM writer or the like and easily copied, so that important programs, data, etc. may be diverted without permission. There is.
In the future, when the memory-IC card becomes common as a floppy disk, its copy protection will become an important issue.

An object of the present invention is to provide a memory-IC card copy protection method and circuit for solving such a problem.

[0005]

SUMMARY OF THE INVENTION The present invention is a copy protection method for a memory-IC card which has a storage circuit inside and is readable from the outside, and which has several address spaces of the memory-IC card. Divided into segments,
By adding one key information to each segment and writing the key information from the outside, the reading result of the memory-IC card is validated, and when the key information is not given from the outside, the reading is performed. The feature is that copy protection is performed by invalidating the result.

Further, according to the present invention, a memory circuit is incorporated inside,
Externally readable memory-A copy protection circuit for an IC card, which stores a first memory in which key information corresponding to each predetermined address segment is written and key information similar to the key information to the outside. A second memory which can be written more, and the key information of the first memory and the key information written in the second memory are compared, and a comparator which can read the memory circuit only when they match And is provided.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram of a memory-IC card 20 having a copy protect circuit according to the present invention. It is assumed that the memory-array 1 can output the contents of the address designated by the address bus 5 to the data bus 8 through the tristate buffer 2 only when the chip select signal 6 is ON. Protect circuit 3
Turns on its output 9 only when the key information corresponding to the upper 8-bit address (hereinafter referred to as an address segment) designated by the address bus 5 is written in advance from the outside. After that, chip select signal 6
By turning on, the output of the AND circuit 4 turns on,
Through the tristate buffer 2, the read result of the memory-array can be output to the data bus 8. In FIG. 1, 7 is a control signal.

Next, the protect circuit 3 will be described with reference to FIG. The protect circuit 3 includes a read only memory (ROM) 12, a random access memory (RAM) 10 and a comparator (CMP) 11.

Key information corresponding to each predetermined address segment is written in the ROM 12,
By writing the same key information to the RAM 10 from the outside, the output of the comparator 11 is turned on for all address segments. In this embodiment, there are 256 address segments, and key information corresponding to each exists. In order to operate this memory-IC card correctly, it is necessary to write 256 pieces of key information from the outside into the RAM 10. If at least one wrong key information is written, the reading result of the memory-card becomes undefined. Even when trying to find the correct key information by trial and error, the number of trials is 256! Because of the above, it is difficult to collect key information.

[0011]

As described above, the present invention has an effect that copy protection can be performed by incorporating a protect circuit in the memory card.

[Brief description of drawings]

FIG. 1 is a block diagram of a memory-IC card including a copy protection circuit of the present invention.

FIG. 2 is a detailed diagram of the copy protection circuit of FIG.

[Explanation of symbols]

1 memory-array 2 tri-state buffer 3 Protect circuit 4 AND circuit 5 address bus 6 Chip select signal 7 control signal 8 data buses 9 Protect signal 10 RAM (random access memory) 11 Comparator 12 ROM (Read Only Memory)

Claims (2)

[Claims] 1. A method of copy protection for a memory-IC card having a memory circuit inside and readable from the outside, comprising: dividing an address space of the memory-IC card into several segments; To the memory-IC card is validated by adding one key information to the above and writing the key information from the outside, and when the key information is not given from the outside, the read result is invalid. A copy protection method for a memory-IC card, characterized in that copy protection is performed by using the above method. 2. A copy protection circuit for a memory-IC card, which has a storage circuit inside and is readable from the outside, wherein key information corresponding to each predetermined address segment is written. The memory, the second memory in which the same key information as the key information can be written from the outside, the key information of the first memory and the key information written in the second memory are compared and match. A copy protection circuit for a memory-IC card, comprising a comparator that enables the storage circuit to be read only when the memory-IC card is read.