JP2002334019A - Programmable logic element and data rewriting system for programmable logic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a programmable logic element which can have its program rewritten with ease, hold secrecy, and easily specify decoding key data used to decode the programmable logic element and a system for rewriting the data of a programmable logic element like this way. SOLUTION: The programmable logic element A is equipped with a decoding circuit 2, a programmable logic circuit 4, a decoding key data writing circuit 6, and a decoding key storage circuit 7 which uses a nonvolatile storage circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmable logic device capable of rewriting program data, and a data rewriting system for a rewritable programmable logic device. The present invention relates to a data rewriting system for a programmable logic element requiring security.

[0002]

2. Description of the Related Art In recent years, paid music and video distribution services have started, and products such as personal computers (PCs), set-top boxes (STBs), and portable terminals corresponding to these services have been released. For data processing such as scrambling of distribution data for such products, encryption and decryption processing, and billing processing, examples of using rewritable programmable logic elements are increasing. This means that if a product has a data processing function using a rewritable programmable logic element, the program data written in the programmable logic element will be changed to a new one even after the product is shipped to the market. This is because a product corresponding to the new program data can be obtained simply by performing the above operation.

For example, if the method of scrambling the distribution data to be distributed to the STB changes, to receive the distribution data according to the new scrambling method, an STB having program data corresponding to the new scrambling method must be prepared. As described above, if the STB has a rewritable programmable logic element, the program data relating to the scramble method written in the programmable logic element of the STB used so far can be used without being replaced with a new STB. Can be replaced with new program data.

However, in a programmable logic element used for such a purpose, it is important to keep data and the like confidential. In other words, in the above example, if rewriting to new program data is performed for a fee, it is necessary to prevent a third party other than the contractor from knowing the contents of the new program data. Therefore, keeping confidentiality is important.

A conventional example of the programmable logic element used as described above will be described with reference to the drawings.
FIG. 4 is a diagram showing a structure of a conventional programmable logic element X. As shown in FIG. 4, the programmable logic element X includes a program data writing circuit 3 and a programmable logic unit 4. In the figure, reference numeral 13 denotes program data for a programmable logic element.

[0006] The operation of the programmable logic element X thus configured will be described. Program data 13 for the programmable logic element supplied from outside to the programmable logic element X is stored in the program data writing circuit 3.
Is written into the programmable logic unit 4. As a result, the programmable logic unit 4 discards the logic operation previously defined in the programmable logic unit 4 and executes the logic operation newly defined in the program data written by the programmable logic element program data 13. .

[0007] Incidentally, there are two types of the programmable logic unit 4, one using a volatile memory and one using a nonvolatile memory. When the programmable logic unit 4 is formed of a volatile memory, the program data writing circuit 3 operates the program data 13 for the programmable logic element every time the power supply of the device including the programmable logic element is turned on.
Must be written to the programmable logic unit 4.

When the programmable logic unit 4 is composed of a nonvolatile memory, only when the program data 13 for the programmable logic device is changed in order to change the contents of the logic operation realized by the programmable logic device. The program data writing circuit 3 writes the new programmable logic element program data 13 into the programmable logic unit 4.

Since the conventional programmable logic element X is configured as described above, it is possible to always rewrite the programmable logic element X with the latest programmable logic element program data as needed. That is, a PC or STB provided with such a programmable logic element X can always be a product provided with the latest program data simply by inputting new program data from the outside.

[0010]

However, as described above, in the case of the conventional programmable logic element X, since the programmable logic element program data 13 is supplied from outside the programmable logic element X,
By connecting a measuring device to the programmable logic element X,
When writing is performed, there is a problem that newly written program data can be read from the outside. In addition, if the structure of the programmable logic element X is known, it is possible to analyze the operation realized by the programmable logic element X from the read contents, which is also a problem.

That is, there is a great advantage that the function can be changed by rewriting the program data even after the conventional product provided with the programmable logic element X in which the program data is rewritable.
There is a drawback in that it is difficult to keep program data related to functions implemented by the programmable logic element X confidential.

Further, in the case of a product such as a PC or STB using such a programmable logic element X, which uses different encryption key data and decryption key data for each product, However, it has a drawback that it is difficult to specify what kind of decryption key data is used for decrypting the programmable logic element X used in a certain product.

Accordingly, the present invention has been made in view of such a problem, and an object of the present invention is to make it possible to easily rewrite program data and to maintain confidentiality. It is another object of the present invention to provide a programmable logic element capable of easily specifying decryption key data used for decrypting a programmable logic element, and a data rewriting system for rewriting data of such a programmable logic element.

[0014]

According to a first aspect of the present invention, there is provided a programmable logic device, comprising: a programmable logic device which encrypts program data for a programmable logic device defining a logic operation of the programmable logic device; A decryption key data writing circuit for inputting decryption key data for decrypting logic element encryption program data, and a non-volatile circuit for storing the decryption key data input by the decryption key data writing circuit A decryption key data storage circuit and the programmable logic element encryption program data, and decryption using the decryption key data stored in the decryption key data storage circuit. Circuit defined in the encrypted program data for the programmable logic element decrypted by the decryption circuit. A programmable logic circuit for implementing an operation, to the decoded programmable logic devices for encrypting program data has been provided with a program data write circuit for writing in the programmable logic circuit, and wherein.

According to a second aspect of the present invention, in the programmable logic element, an encryption program for a programmable logic element, wherein program data for a programmable logic element defining a logic operation of the programmable logic element is encrypted using encryption key data. Identification for identifying a combination of the encryption key data, the decryption key data corresponding to the encryption key data, and the encryption key data and the decryption key data; Key data table and a decryption key data writing circuit for inputting the key data table, and a nonvolatile memory for storing the decryption key data input by the decryption key data writing circuit Storage circuit for decryption key data, which is a security circuit, and inputs the encryption logic program data for the programmable logic element, A decryption circuit for decrypting the data using the decryption key data stored in the decryption key data storage circuit; and a programmable logic element encrypted program data decrypted by the decryption circuit. A programmable logic circuit that implements the logic operation, a program data writing circuit that writes the decrypted encrypted program data for the programmable logic element to the programmable logic circuit, and the identification code data from the key data table. An identification code data read / write circuit to be extracted; and an identification code data storage circuit that is a nonvolatile storage circuit that stores the identification code data extracted by the identification code data read / write circuit. And

According to a third aspect of the present invention, there is provided a data rewriting system for rewriting program data for a programmable logic element, which is written in the programmable logic element according to the second aspect. A key data table storage circuit that is a nonvolatile storage circuit that stores the key data table;
An encryption circuit for inputting the program data, reading the encryption key data from the key data table storage circuit, and using the read key data to encrypt the program data to create the programmable logic element encrypted program data; Program data output means for outputting the encrypted logic element encrypted program data encrypted by the encryption circuit, and decryption key data output means for outputting the decryption key data from the key data table storage circuit And identification code data input / output means for inputting / outputting the identification code data from the key data table storage circuit.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. The embodiment described here is merely an example, and the present invention is not necessarily limited to this embodiment.

(Embodiment 1) First, claim 1 of the present invention
Will be described as a first embodiment with reference to the drawings. As shown in FIG. 1, the programmable logic element A according to the first embodiment includes a decryption circuit 2, a program data writing circuit 3, a programmable logic circuit 4, a decryption key data writing circuit 6, And a decryption key data storage circuit 7 using a nonvolatile storage circuit. In the figure, reference numeral 1 denotes encrypted program data for a programmable logic element, which is obtained by encrypting program data defining the logical operation of the program logic element A. Reference numeral 5 denotes an encrypted program data for creating a programmable logic element. And decryption key data relating to a decryption key for decrypting the encrypted encryption key.

Each component of the programmable logic element A thus configured will be described. The decryption key data writing circuit 6 inputs the decryption key data 5 for decrypting the programmable logic element encrypted program data 1 obtained by encrypting the programmable logic element program data defining the logical operation of the programmable logic element A. I do. The decryption key storage circuit 7 is a non-volatile circuit for storing the decryption key data 5 input by the decryption key data writing circuit 6 and is a decryption key data storage circuit.

The decryption circuit 2 receives the encrypted logic element encryption program data 1 and decrypts it using the decryption key data 5 stored in the decryption key data storage circuit 7. The programmable logic circuit 4 implements the logical operation specified in the encrypted logic device encrypted program data 1 decrypted by the decryption circuit 2.
The program data writing circuit 3 is a program data writing circuit that writes the decrypted encrypted program data 1 for a programmable logic element into the programmable logic circuit 4.

Next, the operation of the programmable logic element A thus configured will be described. First, the decryption key data writing circuit 6 writes the decryption key data 5 into the decryption key storage circuit 7. This writing is usually performed only once when a product including the programmable logic element A is shipped. Although the decryption key data storage circuit 7 according to the present embodiment uses a nonvolatile storage circuit, it may have a structure called “one time” that can be written only once, A structure in which writing can be performed a plurality of times may be used.

Next, the encrypted logic element encrypted program data 1 is input to the decryption circuit 2. Next, the decryption circuit 2 inputs the decryption key data 5 from the decryption key data storage circuit 7 and uses this to decrypt the encrypted logic element encrypted program data 1.

When the decryption of the encrypted logic program data for programmable logic element 1 is completed in the decryption circuit 2, it is written to the programmable logic circuit 4 via the program data writing circuit 3. As a result, the programmable logic circuit 4 discards the logic operation specified in the program data written so far, and realizes the logic operation specified in the newly written programmable logic element encrypted program data 1. Become like

In the first embodiment, since the programmable logic element is configured as described above, program data input to the programmable logic element itself is encrypted,
Since the configuration is such that the encryption can be decrypted inside the programmable logic element, there is an effect that secrecy of the function realized by the programmable logic circuit can be realized.

The product using the programmable logic element A according to the present embodiment has a large number of products,
In addition, in the case of a product having a high degree of confidentiality, the combination of the encryption logic program data 1 for the programmable logic element and the decryption key data 5 is different for each product. It is also possible to use the program data 1 and the decryption key data 5. When the importance of confidentiality is low, the use of one kind of programmable logic element encryption program data 1 and decryption key data 5 common to all products enables management after product shipment and product production. It is also possible to save time and effort.

(Embodiment 2) Next, claim 2 of the present invention
Will be described as a second embodiment with reference to the drawings. As shown in FIG. 2, the programmable logic element B according to the second embodiment includes a decryption circuit 2, a program data writing circuit 3, a programmable logic circuit 4, a decryption key data writing circuit 6, Decryption key data storage circuit 7 using a nonvolatile storage circuit, and identification code data read / write circuit 9
And an identification code data storage circuit 10. In the figure, reference numeral 11 denotes encryption key data used to encrypt the program data for the programmable logic element defining the logic operation of the program logic element B, and 1 denotes the encryption of the program data defining the logic operation of the program logic element B. 5 is used to decrypt the encrypted logic device encrypted program data,
And decryption key data corresponding to the encryption key data 11, 8
Is identification code data for identifying a combination of the encryption key data 11 and the corresponding decryption key data 5,
Reference numeral 12 denotes a key data table including the encryption key data 11 and the decryption key data 5, and the identification code data 8. Reference numeral 13 denotes programmable logic element program data to be newly written to the programmable logic element B.

The decryption key data storage circuit 7 and the identification code data storage circuit 10 use nonvolatile storage circuits. The components of the programmable logic element B configured as described above will be described, but the description of the components that perform the same operation as the programmable logic element A will be omitted.

The decryption key data writing circuit 6 encrypts the programmable logic element program data 13 defining the logic operation of the programmable logic element B using the encryption key data 11 and encrypts the programmable logic element program data. The decryption key data 5 for decrypting 1 is extracted from the key data table 12 and input.

The identification code data read / write circuit 9 extracts the identification code data 8 from the key data table 12. The identification code data storage circuit 10 stores the identification code data 8 extracted by the identification code data read / write circuit 9.

The operation of the programmable logic element B according to the second embodiment will be described.
First, when a product including the programmable logic element B is manufactured and shipped, the decryption key data writing circuit 6 writes the decryption key data 5 into the decryption key storage circuit 7. The identification code data read / write circuit 9
, The identification code data 8 is written into the identification code data storage circuit 10. This writing is usually performed only once when a product having the programmable logic element B is shipped. Although the decryption key data storage circuit 7 according to the present embodiment uses a nonvolatile storage circuit, it may have a structure called “one time” that can be written only once, A structure in which writing can be performed a plurality of times may be used.

The programmable logic element B in which the decryption key data 5 and the identification code data 8 are written as described above.
When rewriting the program data for the programmable logic element that has been written in advance for a product with
First, the identification code data 8 is read from the identification code data storage circuit 10 by the operation of the identification code data read / write circuit 9.

Next, by referring to the key data table 12 using the read identification code data 8, the encryption key data 11 and the decryption key data 5 corresponding to the identification code data 8 are known. be able to. Here, the decryption key data 5 is the decryption key data 5 written at the time of product shipment.

Using the encryption key data 11, the programmable logic element program data 13 to be rewritten is encrypted to create the programmable logic element encrypted program data 1.

Next, the encrypted logic device encrypted program data 1 is input to the decryption circuit 2. Next, the decryption circuit 2 inputs the decryption key data 5 from the decryption key data storage circuit 7 and uses this to decrypt the encrypted logic element encrypted program data 1.

When the decryption of the programmable logic element encrypted program data 1 is completed in the decryption circuit 2, it is written into the programmable logic circuit 4 via the program data writing circuit 3. As a result, the programmable logic circuit 4 discards the logic operation specified in the program data written so far, and realizes the logic operation specified in the newly written programmable logic element encrypted program data 1. Become like

In the second embodiment, since the programmable logic element B is configured as described above, when a different key is used for each product, the programmable logic element used for the product after the product is shipped. The function can be changed without the disadvantage that it is difficult to specify the key used for decrypting the key.

In the second embodiment, the decryption key data 5 and the encryption key data 11 have different values, but may have the same value depending on the encryption and decryption algorithms.

(Embodiment 3) Next, claim 3 of the present invention will be described.
The data rewriting system for programmable logic elements described in (1) will be described as a third embodiment with reference to the drawings. The data rewriting system C for a programmable logic element according to the third embodiment includes, as shown in FIG.
Encrypted program data for programmable logic element 1
, Decryption key data 5, identification code data, encryption key data 11, encryption circuit 14, key data table storage circuit 15, and program data output means 16 for encrypted logic element encrypted program data. And decryption key data output means 17 as output means for decryption key data, and identification code data input / output means 18 as input / output means for identification code data. Also,
In the figure, 13 is program data for a programmable logic device, and B is the programmable logic device described in the second embodiment. The key data table 12 is composed of the decryption key data 5, the encryption key data 11, and the identification code data 8, and this is stored in the key data table storage circuit 15. The key data table storage circuit 15 uses a nonvolatile storage circuit.

Each component of the data rewriting system C for a programmable logic device having the above configuration will be described. The key data table storage circuit 15 stores the key data table 12. The encryption circuit 14 inputs the programmable logic element program data 13 and
From the key data table storage circuit 15 to the encrypted key data 11
Is read out and used for encrypting the program data 13 for the programmable logic element to create the encrypted logic program data 1 for the programmable logic element.

The program data output means 16 outputs the encrypted logic element encrypted program data 1 encrypted by the encryption circuit 14. The decryption key data output means 17 outputs the decryption key data 5 from the key data table storage circuit 15. The identification code data input / output unit 18 inputs and outputs the identification code data from the key data table storage circuit 15.

The operation of the data rewriting system C for a programmable logic element according to the third embodiment will be described below. The programmable logic element for which the data rewriting system C for programmable logic elements rewrites data is the programmable logic element B itself described in the second embodiment.

First, a case where data is written to the programmable logic element B for the first time will be described. First, the encryption key data 11 used to encrypt the programmable logic element program data 13 and the corresponding decryption key data 5 are determined. This may be arbitrarily determined using a random number generator or the like. Next, different identification code data 8 is determined for each product including the programmable logic element B. This may include a serial number, a management code, and the like. The encryption key data 11, the decryption key data 5, and the identification code data 5 determined above are combined into a key data table 12
Is written in the key data table storage circuit 15.

Next, the programmable logic element program data 13 is input to the programmable logic element data rewriting system C. On the other hand, using the determined encryption key data 11, the data is encrypted by the encryption means 14. The encrypted program data for programmable logic element 1 created here is output by the program data output means 16 to the decryption circuit 2 of the programmable logic element B. Similarly, the determined decryption key data 5 is supplied to the decryption key data writing circuit 6 of the programmable logic element B by the decryption key data output means 17 and the determined identification code data 8 is transmitted to the identification code data. The data is output to the identification code data read / write circuit 9 of the programmable logic element B by the data code input / output means 18.

The case where the data of the programmable logic element B is rewritten after shipping a product in which each data is written in the programmable logic element B will be described below.

When rewriting program data,
The identification code data 8 previously written in the programmable logic element B at the time of shipment is read through the identification code data read / write circuit 9 and the identification code data input / output means 18. By inputting the identification code data 8 thus read out to the key data table storage circuit 15, the key data table 12 stored therein is referred to, and the identification code data 8 corresponding to the identification code data 8 is stored. The encryption key data 11 is extracted.

Next, the program data 13 for the programmable logic element to be rewritten is inputted, and the encryption key data 1 extracted as described above is inputted to the encryption means 14.
1 to generate encrypted program data 1 for programmable logic elements. This is output to the programmable logic element B by the program data output means 16, thereby rewriting the program data written in the programmable logic element B.

In the data rewriting system for a programmable logic device according to the present embodiment, the programmable logic device according to the second embodiment is configured to receive program data at the time of product production, and to efficiently rewrite after the product is shipped. Will be able to do it. The system may include a display screen and input devices such as a keyboard and a mouse for an interface with the operator.

[0048]

As described above, according to the programmable logic device of the first aspect of the present invention, a circuit for decrypting the encrypted program data for the programmable logic device, and a decryption circuit for decrypting the program data. By providing a nonvolatile storage circuit for storing a key to be used, confidentiality of a function realized by the programmable logic unit can be realized.

According to the programmable logic device of the second aspect of the present invention, a circuit for decrypting the encrypted program data for the programmable logic device and a key for storing the key used for the decryption are stored. By using a non-volatile memory circuit for storing the identification data and a non-volatile memory circuit for storing the identification data, when a different key is used for each product, the programmable logic used for the product after the product is shipped. The function can be changed without the disadvantage that it is difficult to specify the key used for decrypting the element.

According to the data rewriting system for a programmable logic element according to the third aspect of the present invention, the input / output means of the identification code data read from the programmable logic element and the encryption of the program data for the programmable logic element Storage means for storing a table in which keys used for encryption and decryption and identification data are associated with each other, means for outputting the decryption key data, and a program for a programmable logic element. Providing the data output means enables the programmable logic element according to claim 2 to input program data at the time of product production, and to efficiently rewrite after the product is shipped.

[Brief description of the drawings]

FIG. 1 is a block diagram mainly showing features of a programmable logic element according to a first embodiment of the present invention.

FIG. 2 is a block diagram mainly showing a characteristic portion of a programmable logic element in Embodiment 2 of the present invention.

FIG. 3 is a block diagram mainly showing characteristic portions of a programmable logic element in a third embodiment of the present invention.

FIG. 4 is a block diagram showing an example of a conventional programmable logic element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Encrypted program data for programmable logic elements 2 Decryption circuit 3 Program data writing circuit part 4 Programmable logic circuit 5 Decryption key data 6 Decryption key data writing circuit 7 Decryption key data storage circuit 8 Identification code data 9 Identification code data read / write circuit 10 Identification code data storage circuit 11 Encryption key data 12 Key data table 13 Program data for programmable logic element 14 Encryption circuit 15 Key data table storage circuit 16 Program data output means 17 Decryption key data output Means 18 Identification code data input / output means

Continued on the front page F term (reference) 5B017 AA03 BA07 CA15 5B076 FA01 FA16 5J104 AA01 AA16 EA04 EA17 NA02

Claims (3)

[Claims] 1. A decryption key data writing circuit for inputting decryption key data for decrypting encrypted program data for a programmable logic element, which is obtained by encrypting program data for a programmable logic element that defines the logic operation of the programmable logic element. A decryption key data storage circuit that is a non-volatile circuit that stores the decryption key data input by the decryption key data writing circuit; and inputs the programmable logic element encryption program data. The decryption key data stored in the decryption key data storage circuit, and a programmable logic element encrypted program data decrypted by the decryption circuit. Logic circuit for realizing a logical operation, and encryption for the decrypted programmable logic element Further comprising a program data write circuit for writing program data to the programmable logic circuit, a programmable logic device characterized. 2. The method according to claim 1, wherein the decryption key data for decrypting the program data for the programmable logic element, which defines the logic operation of the programmable logic element using the encryption key data, is used as the decryption key data. A key data table comprising: encryption key data; the decryption key data corresponding to the encryption key data; and identification code data for identifying a combination of the encryption key data and the decryption key data. And a decryption key data writing circuit that inputs the decryption key data, and a decryption key data storage circuit that is a non-volatile circuit that stores the decryption key data input by the decryption key data writing circuit. The programmable logic element encryption program data is input, and stored in the decryption key data storage circuit. A decryption circuit that decrypts using the encryption key data; a programmable logic circuit that implements a logical operation defined by the programmable logic element encrypted program data decrypted by the decryption circuit; A program data writing circuit for writing the encrypted program data for programmable logic elements to the programmable logic circuit; an identification code data reading / writing circuit for extracting the identification code data from the key data table; and the identification code data. An identification code data storage circuit that is a non-volatile storage circuit that stores the identification code data extracted by the read / write circuit. 3. A data rewriting system for rewriting program data for a programmable logic element written in the programmable logic element according to claim 2, wherein the key data table is a nonvolatile storage circuit for storing the key data table. A storage circuit, inputting the program data, reading the encryption key data from the key data table storage circuit, and using the read key data for encrypting the program data to create the programmable logic element encrypted program data; An encryption circuit that performs encryption, program data output means that outputs the encrypted logic element encrypted program data encrypted by the encryption circuit, and decryption that outputs the decryption key data from the key data table storage circuit. Key data output means, and the key data Further comprising the identification code data input means for inputting and outputting the identification code data from the table storage circuit, and characterized by the data rewriting system for a programmable logic device.