JPH11126020A - Integrated circuit and safe data processing method employing the integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IC(integrated circuit) having high security. SOLUTION: The IC is provided with a logic circuit section such as a microprocessor 1 and a processor 2 which is safely protected by a protecting member 3. The processor 2 is connected to the section 2 by data lines 2 at least. The processor 2 is provided with a ciphering engine 11 and a volatile storage element 8 which stores a secret key.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an integrated circuit and a method for secure data processing using a secret key by the integrated circuit.

[0002]

BACKGROUND OF THE INVENTION In the field of pay television, deposit or any other secure data processing environment, the systems or methods used rely on the secure storage of a secret portion of information, ie, a secret key. This secret key is used by the microprocessor to perform cryptographic functions.
In an integrated circuit comprising a microprocessor and a storage element for a secret key, the circuit may be entirely enclosed in a cocoon or maze, or provided with a power supply, ground and / or sense wires. The resulting encapsulation provides security by securely storing the microprocessor and storage elements.

[0003]

However, enclosing the entire circuit portion is considerably complicated in view of the size of the circuit portion in the integrated circuit chip.
In addition, there are several points of connection between the microprocessor and peripheral circuits, each of which can be used by an unauthorized person to obtain information that can be used to find a secret key. Points. Further, if the operation of the microprocessor is halted during the cryptographic operation, the microprocessor's register contains information that can be used by an unauthorized person to derive the private key. Obviously, if the private key is found by an unauthorized person, the system will be compromised immediately. The present invention seeks to provide an integrated circuit and method of the above type with increased security.

[0004]

According to the present invention, there is provided an integrated circuit comprising a logic circuit, preferably a microprocessor, and a safety coprocessor protected by a protection member, said coprocessor comprising: Connected to the logic circuit section by at least a data line, the coprocessor includes a cryptographic engine and a volatile storage element for storing a secret key.

[0005] In this way, a small portion of the circuit portion,
That is, only the safety coprocessor or the safety cell needs to be enclosed in the protective member, and because of the small size of the coprocessor area this confinement is possible in a relatively simple manner with high security. Integrated circuit is provided. All storage and cryptographic functions are contained within the protective member, so that no part of the cryptographic process is visible to any external means at any stage of its operation. Only messages from the microprocessor that are processed by the secure coprocessor, and processed messages, are available on the data line, but the information does not provide any information about the secret key. Thus, even attempting to breach security, it is impossible for a third party to find any information about the private key.

[0006] Since the secret key is stored in volatile storage, any attempt to access the secure coprocessor results in the loss of the secret key. This is because such an attempt is detected by the protection element and results in the loss of power and the consequent destruction of the secret key.

According to the present invention, there is provided a method for secure data processing using a secret key, the method comprising the steps of: loading the secret key into a storage element; Transmitting from the microprocessor to the coprocessor via the data line with the control information; using the secret key to decrypt the information in accordance with the control information in the coprocessor; and authenticating the decrypted information And using the information decrypted according to the control information.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be further described with reference to the drawings, in which the integrated circuit according to the invention is shown in a very schematic manner. By way of example, the integrated circuit shown is to be part of a smart card used in a conditional access module of a pay television decoder system. However, the invention is not limited to such applications. On the contrary, the invention can be used in a wide range of cryptographic applications.

[0009] The integrated circuit comprises a microprocessor 1 and a safety coprocessor 2 enclosed within a protective member 3 of a security wire, which may include power, ground and / or sense wires. Security wire 3 is indicated by the dotted line surrounding coprocessor 2. In an actual integrated circuit, the coprocessor 2 is almost completely covered at least on the top and bottom sides by security wires. As used herein, the term protective member refers to a maze or cover, or encapsulation of power, ground, and / or sense wires,
Alternatively, it can be seen that other active or passive means for preventing access to the coprocessor 2 may be used.

The coprocessor 2 includes a clock line 4 and a data line 5 connected to other circuit parts of the integrated circuit, specifically, to a clock circuit and the microprocessor 1 not shown.
Connected by The coprocessor 2 includes a cryptographic device 6, a control device 7, and a volatile storage element 8 for storing a secret key. The encryption device 6 includes a decryption engine 9, an authentication engine 10, and preferably an encryption engine 11. Furthermore, the cryptographic device 6 includes a one-way functional block 12 for loading a secret key into the storage element 8. The power consumption of the elements of the safety coprocessor 2 is very low and the power is supplied by a battery not shown.

The storage element 8 for the secret key and all cryptographic functions are contained in the protective member 3 so that any part of the cryptographic process is not accessible to external means at any operating stage of the coprocessor 2. Inaccessible. The actual decryption, encryption, and / or authentication functions are not part of the present invention, and therefore, a detailed description of such functions is not required. Any decryption, encryption, or authentication commonly used in the cryptographic process may be performed in the logic portion of coprocessor 2. However, it should be noted that the number of logic elements used for the coprocessor 2 is preferably as small as possible, since this results in a small protection element with very high security.

Attempts to enter the protective member 3 result in contact with any of the sense wires or a short in the ground and power wires, thereby disconnecting the power of the coprocessor 2. Therefore, such an attempt will lead to the deletion of the secret key stored in the storage element 8.

With the integrated circuit described above, data processing is performed in a very secure manner by first loading the secret key into the storage element by sending the seed to the storage element via the one-way function block 12. Is possible. The secret key is loaded into the secure coprocessor via the data line 5 using a one-way function, for example, a one-way hash function, so that the secret key is determined even by an unauthorized person. Is not known, so smart cards cannot be reused.

After loading the secret key into the storage element 8, the microprocessor 1 sends the requested operation to the coprocessor 2 via the data line 5 together with control information and an authentication vector for indicating to the control device 7. The coprocessor 2 can be requested to decrypt the encrypted information that has been encrypted. The coprocessor 2 uses the secret key to decrypt the information, and the decrypted information is authenticated in the usual way. Thereafter, the decrypted information is used by the coprocessor 2 according to the control information, which control information indicates whether the decrypted information should be returned to the microprocessor 1, for example, the next encrypted information from the microprocessor 1. Can be used either as a key for the next decryption stage for the information message that was sent. In the latter case, two or more decryption stages may be performed sequentially in coprocessor 2 without returning decrypted information to microprocessor 1.

The control information in the message supplied by the microprocessor 1 contains information about which decryption or encryption algorithm will be used by the coprocessor 2 and any other required configuration information. May be included. Although coprocessor 2 is shown as comprising a number of individual blocks, it is noted that the actual implementation of this coprocessor can be done in any suitable way.

The invention is not restricted to the embodiments described above, which can be varied in many ways within the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an integrated circuit according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microprocessor 2 Coprocessor 3 Protective member 4 Clock line 5 Data line 6 Cryptographic creation device 7 Control device 8 Volatile storage element 9 Decryption engine 10 Authentication engine 11 Encryption engine 12 One-way function block Reference number F05395A1

Claims (10)

[Claims] 1. An integrated circuit comprising a logic circuit unit such as a microprocessor and a safety coprocessor protected by a protection member, wherein the coprocessor is connected to the logic circuit unit by at least a data line. An integrated circuit, wherein the coprocessor comprises a cryptographic engine and a volatile storage element for storing a secret key. 2. The secure coprocessor according to claim 1, wherein the secure coprocessor comprises a one-way function device, and the storage element is loaded with a secret key by supplying a seed to the one-way function device. Integrated circuit. 3. The cipher creation engine includes: a control device;
3. The integrated circuit according to claim 1, further comprising a decryption engine and an authentication engine. 4. The integrated circuit according to claim 3, wherein said encryption creation engine further includes an encryption engine. 5. The integrated circuit according to claim 1, wherein the protection member includes a power supply, a ground, and / or a security wire including a sense wire. 6. The integrated circuit according to claim 1, wherein the volatile storage element for at least a secret key is powered by a battery. 7. A method for secure data processing using a secret key by using the integrated circuit according to claim 1, wherein the secret key is stored in the storage element. Loading; transmitting encrypted information along with control information from the microprocessor to the coprocessor via a data line; and the secret key for decrypting the information according to the control information in the coprocessor. A method comprising: authenticating decrypted information; and using the information decrypted according to the control information. 8. The decryption information according to claim 7, wherein the decrypted information is used as a decryption key in the coprocessor to decrypt further encrypted information received from the microprocessor. The described method. 9. The method according to claim 7, wherein the decrypted information is returned to the microprocessor. 10. The method according to claim 7, wherein the secret key is loaded into a storage element by applying a one-way function to a seed.