CN103647654B - A kind of power distribution terminal key management method based on trust computing - Google Patents

Abstract

The present invention relates to a trusted computing-based power distribution terminal key management method, the method comprising: (1) constructing an ETM key structure according to the power distribution terminal; (2) generating a power distribution terminal identity certificate based on the ETM key ; (3) Store and manage power distribution terminal data based on ETM key; (4) Remotely prove the status of power distribution terminal based on ETM key. The keys involved in the power distribution terminal of the present invention are all stored in the power trusted module ETM, which provides hardware-level protection for the key, and the security of the key further ensures the security of the key operation result; based on the identity encryption of the power distribution terminal The terminal integrity status of the key signature can realize the identity and status authentication of the power distribution terminal in the grid communication, and further enhance the security of the grid communication.

Description

A Key Management Method for Distribution Terminals Based on Trusted Computing

technical field

The invention relates to a power system management method, in particular to a trusted computing-based power distribution terminal key management method.

Background technique

As the development trend of the future power grid, the smart grid is increasingly becoming the focus of the development of countries all over the world. The smart grid based on the integrated, high-speed two-way communication network is applied through advanced sensing and measurement technologies, advanced control methods and advanced Decision support system technology to achieve the reliability, safety, economy, high efficiency, environmental friendliness and safe use of the power grid. An important feature of the smart grid is distribution automation.

The distribution terminal in the distribution automation has the function of detecting and monitoring the operation of the distribution line. Due to the complexity and uncertainty of the environment, the security problems it faces are more complicated than those of the PC system. Power distribution terminals may be subject to threats such as physical damage, virus Trojan horses, and security threats from the mobile Internet. Therefore, in response to these threats, power distribution terminals generally have the following security requirements, such as data integrity, data encryption, and non-repudiation. In order to improve the security of power distribution terminals, the method of using OpenSSL encryption development kit to test the security protection ability of power distribution terminals, and the use of hash operation and asymmetric encryption technology to realize the integrity check of commands and the identity of the master station of distribution network verify. And the power distribution terminal uses asymmetric encryption technology to perform one-way identity authentication and message integrity protection for the power distribution master station, and puts forward the idea of external security module to reduce the transformation of power distribution terminal equipment. Although the above security schemes can improve the security of power distribution terminals to a certain extent, none of these schemes consider the security management of keys. Once the keys are leaked or stolen, no matter how strong the security scheme is, it will not be effective.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a key management method for power distribution terminals based on trusted computing. The method designs an electric trusted module ETM (Electrical Trusted Module), including the key Key distribution terminal identity certificate generation, data security storage and state authentication. In terms of key security management, trusted computing is a good solution. Trusted computing is a new technology for information system security. The main idea is to introduce a security chip into the computer hardware platform architecture to improve the security of the terminal system. In trusted computing, keys are stored in a tree structure, SRK is used as a primary key (also known as the master key) and stored in a secure area, and the rest of the keys are directly or indirectly protected by it. Its protection method is that the parent key encrypts the child key. The advantage of trusted computing over traditional security is that the outside world cannot arbitrarily obtain information in hardware chips with security functions.

The object of the present invention is to adopt following technical scheme to realize:

A key management method for power distribution terminals based on trusted computing, the improvement of which is that the method includes:

(1) Construct the ETM key structure according to the power distribution terminal;

(2) Generate a distribution terminal identity certificate based on the ETM key;

(3) Store and manage power distribution terminal data based on ETM keys;

(4) Remotely prove the status of the power distribution terminal based on the ETM key.

Preferably, in the step (1), the ETM key solidifies the ETM key slot, and the key slot storage binding key handle includes: ETM_IDENTITY_KEY_PRIV-identity key private key handle, ETM_IDENTITY_KEY_PUB-identity key public key handle, ETM_SMS4_KEY_1 - SMS4 - Symmetric key handle 1, ETM_SMS4_KEY_2 - SMS4 - Symmetric key handle 2, ETM_SMS4_KEY_3 - SMS4 - Symmetric key handle 3 and ETM_SMS4_KEY_4 - SMS4 Symmetric key handle 4.

Preferably, the step (2) includes generating the identity certificate of the power distribution terminal security chip ETM based on the power CA system.

Further, the electric power CA system includes a three-level authentication model; the first layer is the national network root CA; the second layer is the secondary CA issued by the national network root CA, which is used for network provincial units; the third layer is The third-level CA issued by the second-level CA is used for prefecture-level units.

Preferably, said step (2) includes

(2.1) The chip manufacturer generates a pair of public and private keys when producing ETM, and sends a certificate generation request to the registration center of the level 2 CA;

(2.2) The registration center enters the ETM information into the database and forwards the certificate request to the certification center;

(2.3) The certification center uses the CA private key to issue a digital certificate through the encrypted card device;

(2.4) The certification center stores the digital certificate in the certificate database for backup, and returns the digital certificate to the registration center;

(2.5) The registration center returns the digital certificate and the public key certificate of the CA to the chip manufacturer;

(2.6) The chip manufacturer stores the previously generated private key and the two certificates returned by the registration center into the ETM chip.

Preferably, the step (3) includes storing and managing the generated keys and data encryption and decryption.

Further, the key generation includes cryptographic algorithms supported by ETM, including asymmetric cryptographic algorithm SM2 for generating identity keys; and symmetric cryptographic algorithm SMS4 for data encryption and decryption.

Furthermore, the data involved in the power distribution terminal is encrypted and decrypted inside the chip to ensure the security of the key operation.

Preferably, said step (4) includes

(4.1) The power distribution terminal uses the identity key to sign the PCR;

(4.2) According to different CAs that issue identity certificates, the certificates sent by the power distribution terminal to the remote party are also different;

(4.3) The remote party verifies the identity certificate. If the identity certificate is verified, continue to use the identity certificate to verify the PCR signature. If the PCR signature is verified, compare the PCR value with the reference value. If they are consistent, it indicates that the terminal status verification is successful; otherwise, the verification fails and the The terminal state is not trusted.

Compared with the prior art, the beneficial effects of the present invention are:

1) The keys involved in the power distribution terminal are all stored in the power trusted module ETM, which provides hardware-level protection for the keys, and the security of the keys further ensures the security of the key operation results;

2) The use of ETM can guarantee the integrity of power distribution terminal equipment and resist malicious software and malicious behavior of users;

3) ETM is designed for the characteristics of power distribution terminal equipment, its use will not affect the normal function of power distribution terminal, and will not cause large additional load to power distribution terminal;

4) The identity certificate based on the identity key of the power distribution terminal is issued by the State Grid CA system, which realizes seamless integration with the existing State Grid CA architecture and facilitates unified deployment and management;

5) Based on the terminal integrity status signed by the identity key of the distribution terminal, the identity and status authentication of the distribution terminal in the grid communication can be realized, and the security of the grid communication can be further enhanced.

Description of drawings

Fig. 1 is a flow chart of a key management method for power distribution terminals based on trusted computing provided by the present invention.

Fig. 2 is a flowchart of an identity certificate based on trusted computing-based power distribution terminal key management method provided by the present invention.

Fig. 3 is a flow chart of remote attestation of a trusted computing-based power distribution terminal key management method provided by the present invention.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

The present invention provides a key management method for power distribution terminals based on trusted computing, specifically as follows:

(1) Design the key structure of the power trusted module ETM according to the specific characteristics of the power distribution terminal;

Considering the limited key space and the simplicity of key use in the power trusted module ETM used in power distribution terminals, unlike the cumbersome key management system of TPM/TCM chips, ETM directly solidifies several key slots, Provide corresponding cryptographic operations such as key generation, encryption and decryption, and signature.

Different from TPM/TCM, ETM public key operations are all completed in ETM, so ETM needs to provide command operations such as public key encryption and signature verification, as well as supporting commands such as public key certificate import and generation.

The power trusted module ETM is similar to the trusted computing security chip TPM/TCM. It is deployed on power industry equipment such as power distribution terminals. The chip has cryptographic computing capabilities and secure storage capabilities, and provides trusted computing similar to TPM/TCM externally. Capabilities such as hardware identification, integrity measurement and storage, remote attestation, etc.

The key handles corresponding to the key slots of ETM include: ETM_IDENTITY_KEY_PRIV (identity key private key handle), ETM_IDENTITY_KEY_PUB (identity key public key handle), ETM_SMS4_KEY_1 (SMS4 symmetric key handle 1), ETM_SMS4_KEY_2 (SMS4 symmetric key handle 2 ), ETM_SMS4_KEY_3 (SMS4 symmetric key handle 3), ETM_SMS4_KEY_4 (SMS4 symmetric key handle 4).

(2) Generation and management of distribution terminal identity certificates based on ETM keys;

In order to ensure a higher level of security and facilitate unified management, various certificates such as identity certificates involved in the power distribution terminal security chip ETM are generated based on the power CA system.

The Power CA system is based on a three-level authentication model. The first layer is the general root CA of the State Grid, the second layer is the secondary CA issued by the national network general root CA, which is used for network provincial units; the third layer is the tertiary CA issued by the secondary CA, which is used for prefectures and cities level unit. The general root CA of the State Grid of the power system is the source of all certificate authentications. Therefore, each ETM will preset the certificate of the general root CA inside the chip when it leaves the factory.

As shown in Figure 2, the generation of the ETM identity certificate depends on the chip manufacturer sending a corresponding request to the power CA system. Depending on the applicable environment of the power distribution terminal, the CA that issues the identity certificate is also different. If the power distribution terminal is deployed and used by the network provincial company, the ETM chip manufacturer needs to submit an application to the level 2 CA of the power system.

1) Chip manufacturers use ETM to generate a pair of public and private keys when producing ETM, and send a certificate generation request to the registration center of level 2 CA;

2) The registration center enters the ETM information into the database, and forwards the certificate request to the certification center;

3) The certification center uses the encryption card device to use the CA private key to issue a digital certificate;

4) The certification center stores the digital certificate in the certificate database for backup, and returns the digital certificate to the registration center;

5) The registration center returns the digital certificate and the public key certificate of the CA to the chip manufacturer;

6) The chip manufacturer stores the previously generated private key and the two certificates returned by the registration center into the ETM chip.

(3) Data storage management of distribution terminals based on ETM keys;

Data storage management of power distribution terminals based on ETM keys includes:

1) Key generation, including the key generation process of the cryptographic algorithm supported by ETM;

2) Data encryption and decryption, including the data encryption and decryption process supported by ETM.

The cryptographic algorithms supported by ETM include the asymmetric cryptographic algorithm SM2 and the symmetric cryptographic algorithm SMS4. The SM2 key is mainly used for identity key generation, and the SMS4 key is used for data encryption and decryption.

The ETM key generation process is that there are four key slots inside the ETM to store four SMS4 keys, which correspond to fixed key handles for the convenience of the application layer. When generating a key, the corresponding key handle must be specified. The internal hardware generates a new key according to the received instruction, and at the same time binds it with the corresponding key handle and puts it into the corresponding key slot.

The advantage of ETM data encryption and decryption is that the hardware can guarantee the security of cryptographic operations, and the data involved in power distribution terminals can only be encrypted and decrypted inside the chip.

The ETM data encryption and decryption process is to issue an instruction to the ETM chip to encrypt using a symmetric cryptographic algorithm, specify the encryption key handle, and given the data to be encrypted, the chip will return the encrypted data after the encryption is completed inside the chip. Decryption is similar.

(4) Remote proof of power distribution terminal status based on ETM key;

During the start-up and operation of the power distribution terminal, the platform configuration register PCR (PlatformConfiguration Register) of ETM records the terminal status, and the PCR based on the ETM identity key signature can prove the terminal status to the remote party.

The PCR of the ETM stores the integrity measurement values of all operating components of the terminal, which are accumulated and extended to the PCR according to the order in which the components start and run. They cannot be changed independently, and truly reflect the operating status of the terminal.

As shown in Figure 3, the power distribution terminal uses the identity key to sign the PCR; depending on the CA that issues the identity certificate, the certificate sent by the power distribution terminal to the remote party is also different. If the identity certificate is issued by a level 2 CA, the power distribution The terminal sends the identity certificate, level 2 CA certificate together with the signed PCR to the remote party; the remote party verifies the identity certificate, if the verification is passed, it will continue to use the identity certificate to verify the PCR signature, and if the verification is passed, compare the PCR value with the reference value , if they are consistent, it means that the proof of the terminal state is successful, otherwise the proof fails, and the terminal state is not credible.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the scope of the claims of the present invention.

Claims (8)

1. a kind of power distribution terminal key management method based on trust computing, it is characterised in that methods described includes：

(1) electric power trusted module ETM key structures are built according to distribution terminal；

(2) the distribution terminal letter of identity based on ETM keys is generated；

(3) ETM key storages are based on and distribution terminal data are managed；

(4) distribution terminal state is proved based on ETM secret key remotes；

The step (2) includes：

(2.1) a pair of public and private keys are produced during chip manufacturer production ETM, certificates constructing request is sent to two grades of CA registration center； Two grades of CA net total root CA by state and signed and issued, for netting provincial unit；

(2.2) ETM Data Enter databases are forwarded certificate request to authentication center by registration center；

(2.3) digital certificate is signed and issued by encrypting card apparatus using the CA private keys by authentication center；

(2.4) digital certificate is stored in certificate data library backup by authentication center, and digital certificate is returned to registration center；

(2.5) registration center returns to digital certificate and the public key certificate of the CA to chip manufacturer；

(2.6) two certificates that the private key generated before and registration center return are stored in ETM chips by chip manufacturer.

2. a kind of power distribution terminal key management method based on trust computing as claimed in claim 1, it is characterised in that described ETM keys are solidificated in ETM key grooves in step (1), and its key groove storage Binding key handle includes：ETM_IDENTITY_ KEY_PRIV- identity key private keys handle, ETM_IDENTITY_KEY_PUB- identity key public keys handle, ETM_SMS4_KEY_ 1-SMS4- symmetric keys handle 1, ETM_SMS4_KEY_2-SMS4- symmetric keys handle 2, ETM_SMS4_KEY_3-SMS4- pairs Claim key handles 3 and ETM_SMS4_KEY_4-SMS4 symmetric keys handle 4.

3. a kind of power distribution terminal key management method based on trust computing as claimed in claim 1, it is characterised in that described Step (2) includes generating distribution terminal safety chip ETM letter of identity based on electric power CA systems.

4. a kind of power distribution terminal key management method based on trust computing as claimed in claim 3, it is characterised in that described Electric power CA systems include three-level authentication model；First layer is that total root CA nets in state；The second layer is that two grades of CA that total root CA is signed and issued net in state, For netting provincial unit；Third layer is the three-level CA that two grades of CA are signed and issued, for prefecture-level unit.

5. a kind of power distribution terminal key management method based on trust computing as claimed in claim 1, it is characterised in that described Step (3) includes storing and managing the key and data encrypting and deciphering of generation.

6. a kind of power distribution terminal key management method based on trust computing as claimed in claim 5, it is characterised in that ETM The cryptographic algorithm of support has asymmetric cryptographic algorithm SM2 and symmetric cryptographic algorithm SMS4, SM2 to be used for the generation of identity key, SMS4 is used for data encrypting and deciphering.

7. a kind of power distribution terminal key management method based on trust computing as claimed in claim 5, it is characterised in that distribution Operation is encrypted and decrypted in chip internal in the data that terminal is related to, the security for ensuring cipher key operation.

8. a kind of power distribution terminal key management method based on trust computing as claimed in claim 1, it is characterised in that described Step (4) includes：

(4.1) distribution terminal is signed using identity key to platform configuration register PCR；

(4.2) according to the different CA for signing and issuing letter of identity, the certificate that distribution terminal is sent to remote parties is also different；

(4.3) remote parties checking letter of identity, letter of identity is verified, then continuation letter of identity checking PCR signatures, PCR Signature verification passes through, then is compared PCR value with reference value, unanimously then shows that the SOT state of termination is proved successfully；Otherwise failure is proved, should The SOT state of termination is insincere.