TWI668971B - A modem device and a method for verifying data - Google Patents

Abstract

The disclosure provides a modem device with a verification data function. The modem device has a communication unit, a storage unit and a processing unit. The communication unit receives and transmits signals. The storage unit stores reference authentication information and device authentication information. The processing unit is coupled to the communication unit storage unit. When the processing unit receives a check instruction from the analog connection modem terminal system, the processing unit verifies whether the device verification information is valid according to the reference verification information. The reference authentication information has the certificate information of the modem terminal system. This disclosure and the corresponding method of verifying the information.

Description

Modem device and method for verifying data

The invention relates to a data verification technology, and in particular to a data machine device and a method for verifying data with a data verification mechanism.

In order to maintain the security of the data transmission between the modem device and the cable modem termination system (CMTS), the data transmission between the existing modem device and the modem terminal system adopts the wired cable data service interface specification (Data- Over-Cable service interface specifications (DOCSIS) and adhere to the security specifications that they have developed. To this end, the modem device stores a plurality of verification data correspondingly, so as to encrypt and decrypt the data to be transmitted by the verification data. In addition, when the modem device performs a firmware update, the modem device also determines whether the source of the firmware is correct based on the verification data.

In the process of manufacturing the modem device, in order to ensure that the verification data stored in the modem device is correct, the manufacturer will actually connect the modem device to the modem terminal system and perform a series of verifications to ensure the correctness of the verification data. Sex. However, the verification process is time-consuming and labor-intensive. In particular, if verification is performed on the production line, it will consume a lot of time and resources and reduce production efficiency. Based on this, how to provide a simpler verification method is a subject devoted by those skilled in the art.

The invention provides a modem device and a method for verifying data, so as to verify the data without being connected to the terminal system of the modem, thereby simplifying the process and time of verifying the data.

The method for verifying data disclosed in this disclosure is applicable to modem devices. This modem device stores reference verification information and device verification information. The method for verifying data has the steps of: receiving a check instruction; verifying whether the device verification information is legal according to the reference verification information, wherein the reference verification information is stored in the modem device and includes the credential information of the modem terminal system.

The modem device disclosed herein has a function of verifying data. The modem device has a communication unit, a storage unit and a processing unit. The communication unit receives and transmits signals. The storage unit stores reference authentication information and device authentication information. The processing unit is coupled to the communication unit storage unit. When the processing unit receives a check instruction from the analog connection modem terminal system, the processing unit verifies whether the device verification information is valid according to the reference verification information. The reference authentication information has the certificate information of the modem terminal system.

Based on the foregoing, in the disclosed modem device and verification data method, since the modem device stores reference verification information corresponding to the modem terminal system, the modem device will not be connected to the modem terminal system. The device verification information of the modem device is verified by referring to the verification information. Based on this, the disclosed modem device and method for verifying data simplifies the method for verifying data and reduces the time consumed.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

Please refer to FIG. 1. FIG. 1 is a system architecture diagram of a modem device according to an embodiment of the present disclosure. The modem device 100 is a user-side modem, which provides a user networking function. For example, the modem device 100 can be connected to a cable modem termination system (CMTS), and communicate with other servers and modems. Data exchange.

In an embodiment of the present disclosure, the modem device 100 is suitable for a network environment connected by a coaxial cable (Hybrid fiber-coaxial, HFC). The modem device 100 can be applied as a cable modem (CM) or an embedded multimedia terminal adapter (eMTA) that supports voice calls.

The modem device 100 includes a communication unit 110, a storage unit 120, and a processing unit 130.

The communication unit 110 is implemented by a communication chip. The communication chip can support Global System for Mobile Communication (GSM), Personal Handy-phone System (PHS), and Code Multiple Acquisition (Code). Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, Long Term Evolution (LTE) system, Worldwide Interoperability for Microwave Access (WiMAX) system , Wireless fidelity (Wi-Fi) system or Bluetooth signal transmission components.

The storage unit 120 stores necessary codes and data for operating the modem device 100. The storage unit may be any type of fixed or removable Random Access Memory (RAM), Read-Only (Read-Only) Memory (ROM), flash memory (Hard Disk Drive, HDD), solid state drive (SSD) or similar components or a combination of the above components.

In this embodiment, the data exchange between the modem device 100 and the modem terminal system will comply with the data-over-cable service interface specifications (DOCSIS) of the cable. DOCSIS defines a Baseline Privacy Interface (BPI) to encrypt transmitted data. Therefore, the storage unit 120 stores the device verification information 122. With the device verification information 122, the processing unit 130 is able to encrypt and decrypt the data to be transmitted to meet the specifications defined by the BPI.

The device verification information 122 includes at least verification data regulated by the BPI, such as: root certificate, authorized device certificate, manufacturer certificate, data device certificate, private key and other data, but is not limited thereto. Because DOCSIS has many different versions, and the corresponding BPI specifications are not the same in different DOCSIS versions. Therefore, the data actually recorded in the device verification information 122 may be adjusted due to design and implementation, and the disclosure is not limited thereto.

The processing unit 130 is connected to the communication unit 110 and the storage unit 120 and is used to run codes and necessary functions of the modem device 100. The processing unit can be a central processing unit (CPU), or other programmable general purpose or special purpose microprocessor (Microprocessor), digital signal processor (DSP), programmable A controller, an Application Specific Integrated Circuit (ASIC) or other similar components or a combination of the above components, the disclosure is not limited thereto.

In order to ensure that the device verification information stored in the modem device is correct, after the manufacturing is completed, the manufacturer will actually connect the modem device 100 with the modem terminal system to confirm the correctness of the device verification information 122. Since the verification process consumes a lot of time resources, in the present disclosure, the storage unit 120 stores the reference verification information 124.

The reference verification information 124 has a variety of different certificates issued by Cable Television Laboratories (CableLabs), and has the certificate information of the modem terminal system. The certificate information such as, but not limited to, the DOCSIS Root CA Certificate or Service Provider Root CA Certificate), Root Public Key.

Since the storage unit 120 stores the reference verification information 124, the modem device 100 can verify the legitimacy and correctness of the device verification information 122 by referring to the verification information 124, thereby replacing the verification process performed by the modem terminal system.

Specifically, please refer to FIG. 2, which illustrates a flowchart of a method for verifying data according to an embodiment of the present disclosure.

In step S210, the processing unit 130 receives an analog connection modem terminal system check instruction. The analog connection modem terminal system check command is used to check whether the device verification information 122 stored in the modem device 100 is correct, so as to establish a connection through the device verification information 122. The code of the simulation connection modem terminal system check command is built into the modem device 100, or is stored in the firmware, and the simulation is input and executed through a command-line interface (CLI) command Wire modem terminal system check instruction.

In step S220, the processing unit 130 verifies whether the device verification information 122 is valid according to the reference verification information 124 stored in the storage unit 120.

Specifically, the reference verification information 124 stores credential information authorized by CableLabs, and the device verification information 122 stores verification information held by the modem device 100. Therefore, if the device verification information 122 held by the modem device 100 is valid, it will be the same as the certificate information carried by the reference verification information 124, or the device verification information 122 may be bidirectionally encrypted and encrypted through the reference verification information 124. Decrypt.

The steps of the processing unit 130 verifying whether the device verification information 122 is legal in step S220 will be further described below. Of course, because the encryption methods specified in different versions of DOCSIS are not the same, the following will describe the specifications of different versions of DOCSIS in different embodiments.

Please refer to FIG. 3, which is a detailed flowchart of a method for verifying data according to an embodiment of the present disclosure. In the embodiment of FIG. 3, the data machine device 100 and the data machine terminal system use DOCSIS 3.1 version for data exchange.

In this embodiment, the credential information stored in the reference verification information 124 includes a reference root certificate (ROOT CA Certificate) and a reference authorized device certificate (Device CA Certificate) of the modem terminal system. The device authentication information 122 includes a root certificate, an authorized device certificate, a data device certificate (Cable Modem Certificate, CM Certificate), and a CM Private Key.

In step S310, the processing unit 130 compares each bit of the reference root certificate with the root certificate to determine whether the root certificate is valid. Specifically, refer to the public certificate (DOCSIS 3.1 Root CA Certificate) issued by CableLabs as the root certificate. The root certificate stored in the storage unit 120 should be consistent with the reference root certificate. If any one bit is different, it means that the reference root certificate is inconsistent with the root certificate, and the root certificate is wrong. In addition, the processing unit 130 executes step S380 to determine that the verification information is incorrect, and generates an error prompt (for example, a sound prompt, a light signal, or a text prompt is displayed on a display screen, and the present disclosure is not limited thereto).

In step S320, the processing unit 130 compares whether each bit of the reference authorized device certificate and the authorized device certificate are the same to determine whether the authorized device certificate is legitimate.

The reference device certificate is a public certificate issued by CableLabs (DOCSIS 3.1 Device CA Certificate). The authorized device certificate stored in the storage unit 120 should be consistent with the reference authorized device certificate. If any one bit is different, it means that the authorized device certificate is the wrong authorized device certificate. At this time, the processing unit 130 also executes step S380.

In step S330, the processing unit 130 checks whether the source of the data device certificate is legal according to the authorized device certificate, and determines whether the media access address of the data device certificate is the same as the media access address of the modem device.

In this embodiment, the data device certificate is issued based on the authorized device certificate and the media access control address (MAC address) of each modem device 100. Therefore, the processing unit 130 retrieves the Device CA Public Key carried in the authorized device certificate, and verifies the digital signature (CM Certificate Signature) of the source of the data device certificate through an asymmetric encryption algorithm (such as: RSA algorithm). )is it right or not. In addition, the processing unit 130 further compares the media access control address (CM MAC address) of the modem device 100 being tested with the media access control address (CM Certificate MAC address) in the data device certificate. If the digital signature of the data device certificate source is correct and the media access control address is also correct, the processing unit 130 determines that the data device certificate is legitimate.

Conversely, if the processing unit 130 determines that either the digital signature of the data device certificate source or the media access control address is incorrect, the data device certificate is illegal, and the processing unit 130 executes step S380.

It should be noted that the operation method for verifying whether the digital signature of the data device credential source is correct through an asymmetric encryption algorithm (such as: RSA algorithm) is a technique well known to those skilled in the art, and is not repeated here.

In step S340, the processing unit 130 determines whether the public key (CM Certification Public Key) of the data device certificate is the same as the public key (CM Public Key) stored by the modem device 100 to determine whether the public key stored by the modem device is correct.

Specifically, each modem device 100 will have its own public key and private key, and the data device certificate will carry the public key belonging to the modem device 100. Therefore, the processing unit 130 determines whether the public key of the data device certificate is consistent with the public key of the data device device 100. If not, it means that the data device certificate does not belong to the modem device 100 under test, and the public key of the data device certificate is incorrect. At this time, the processing unit 130 executes step S380. Encrypting and decrypting data by using a public key and a private key, and exchanging a public key by a certificate are techniques well known to those skilled in the art, and are not repeated here.

In step S350, the processing unit 130 encrypts the text string using the private key, and decrypts the encrypted text string using the public key stored in the modem device to obtain the decrypted text string. According to the technology of applying public and private keys in the field of cryptography, the data encrypted with the private key should be able to be decrypted by the public key. Therefore, the processing unit 130 directly directly encrypts and decrypts the test text with the public key and the private key verified in step S340.

In step S360, the processing unit 130 determines whether the character string is the same as the decrypted character string. If the text string is the same as the decrypted text string, it means that the private key is correct. Conversely, if the text string is different from the decrypted text string, it means that the public key and private key cannot be encrypted and decrypted normally, and the processing unit 130 executes step S380.

In step S370, the processing unit 130 determines that the private key is correct, indicating that all information in the device verification information is legal information, and ends the verification process.

Please refer to FIG. 4, which is a detailed flowchart of a method for verifying data according to another embodiment of the present disclosure. In the embodiment of FIG. 4, the data device 100 and the data terminal system use DOCSIS 3.0, DOCSIS 2.0, or DOCSIS 1.1 to perform data exchange.

3 is similar to the embodiment of FIG. 4 except that the reference authentication information 124 and the device authentication information 122 of the embodiment of FIG. 4 do not have a reference root certificate and a root certificate, and a reference authorized device certificate and an authorized device certificate. However, compared with the embodiment of FIG. 3, the credential information of the reference verification information 124 in the embodiment of FIG. 4 includes a reference root public key (ROOT Public Key). The device verification information 122 includes a root public key, a manufacturer CA certification, a data device certificate (Cable Modem Certificate, CM Certificate), and a private key (Cable Modem Private Key, CM Private Key).

In step S410, the processing unit 130 compares whether the reference root public key and each bit of the root public key are the same to determine whether the root public key is valid. For example, the reference public key is a public public key authorized by CableLabs (for example: DOCSIS 3.0 Root Public Key). The root public key stored in the storage unit 120 should be consistent with the reference root public key. If any one bit is different, it means that the reference root public key is not the same as the root public key, and the root public key is wrong. And, the processing unit 130 executes step S480. The specific content of step S480 is consistent with step S380 of FIG. 3, and details are not described herein again.

In step S420, the processing unit 130 verifies whether the source of the manufacturer certificate is valid according to the root public key. Specifically, the processing unit 130 verifies whether the digital signature (Manufacturer CA Certification Signature) of the manufacturer certificate is correct through an asymmetric encryption algorithm (such as an RSA algorithm) according to the root public key. If the digital signature of the manufacturer's certificate is correct, it indicates that the source of the manufacturer's certificate is legitimate. However, if the digital signature of the manufacturer certificate is incorrect, at this time, the processing unit 130 executes step S480.

In step S430, the processing unit 130 checks whether the source of the data device certificate is legal according to the manufacturer certificate, and determines whether the media access address of the data device certificate is the same as the media access address of the modem device.

In this embodiment, the data device certificate is issued based on the manufacturer's certificate and the media access control address (MAC address) of each modem device 100. Therefore, similar to step S330, the processing unit 130 retrieves the manufacturer CA Certificate Public Key carried in the manufacturer certificate, and verifies the source of the manufacturer certificate through an asymmetric encryption algorithm (such as: RSA algorithm). Is the digital signature (CM Certificate Signature) correct? In addition, the processing unit 130 further compares whether the media access control address (CM MAC address) of the modem device 100 under test is consistent with the media access control address (CM Certificate MAC address) in the data device certificate. If the digital signature of the data device certificate source is correct and the media access control address is also consistent, the processing unit 130 determines that the data device certificate is legitimate. However, if the processing unit 130 determines that the data device certificate is illegal, the processing unit 130 executes step S480.

The details and processes of steps S440 to S480 in the embodiment of FIG. 4 are the same as steps S340 to S380 of FIG. 3, and details are not described herein again.

Please refer to FIG. 5, which illustrates a detailed flowchart of a method for verifying data according to another embodiment of the present disclosure. In this embodiment, the modem device 100 is applied to an embedded multimedia terminal adapter (eMTA) that supports voice calls.

In this embodiment, the certificate information of the reference verification information 124 includes a reference root certificate (Service Provider Root CA Certificate) and a reference public key (Root CA Certificate Public Key). The device verification information 122 includes a root certificate, a MTA Manufacturer CA Certificate, and a data device certificate.

In step S510, the processing unit 130 compares each bit of the reference root certificate with the root certificate to determine whether the root certificate is valid.

The reference root certificate is a Service Provider Root CA Certificate issued by CableLabs to the service provider. The root certificate stored in the storage unit 120 should be consistent with the reference root certificate. If any one bit is different, it means that the reference root certificate is inconsistent with the root certificate, and the root certificate is wrong. In addition, the processing unit 130 executes step S580 to determine that the verification information is incorrect, and generates an error prompt. The specific content of step S580 is consistent with step S380 of FIG. 3, and details are not described herein again.

In step S520, the processing unit 130 checks whether the source of the manufacturer certificate is legitimate according to the reference public key.

Specifically, CableLabs uses the technical specifications of PacketCable. And this technical specification has a corresponding intermediary certificate (PacketCable Root CA Certificate). In this embodiment, a MTA Manufacturer CA Certificate is issued from this intermediary certificate. In order to simplify the verification process, in this embodiment, the public key of the intermediary certificate is stored in the modem device 100 in advance in the command line interface of the firmware of the modem device 100 as a reference public key.

Based on this, when step S520 is executed, the processing unit 130 verifies whether the digital signature of the manufacturer's certificate source is correct according to the reference public key and an asymmetric encryption algorithm (such as an RSA algorithm). If it is correct, the manufacturer's certificate is judged to be a legitimate manufacturer's certificate issued by an intermediary certificate. Otherwise, the processing unit 130 executes step S580.

In step S530, the processing unit 130 determines whether the data device certificate is valid according to the manufacturer certificate, and determines whether the media access address of the data device certificate is the same as the media access address of the data device.

In this embodiment, the MTA Device Certificate is issued based on the manufacturer's certificate and the media access control address (MAC address) of each modem device 100. Therefore, similar to step S430, the processing unit 130 will retrieve the public key (MTA Manufacturer CA Public Key) carried in the manufacturer certificate, and verify the source of the data device certificate through an asymmetric encryption algorithm (such as: RSA algorithm) Is the digital signature (MTA Device Certificate Signature) correct? In addition, the processing unit 130 further compares whether the media access control address (MTA Device MAC Address) of the modem device 100 being tested is consistent with the media access control address (MTA Device Certificate MAC Address) in the data device certificate. To check if the media access control location in the data device certificate is correct. If the digital signature of the data device certificate source is correct and the media access control address of the data device certificate is also correct, the processing unit 130 determines that the data device certificate is legitimate. If the processing unit 130 determines that the data device certificate is illegal, the processing unit 130 executes step S580.

In step S540, the processing unit 130 determines whether the public key (MTA Device Certificate Public Key) of the data device certificate is the same as the public key (MTA Device Public Key) stored by the modem device 100 to determine whether the public key stored by the data device is correct.

In step S550, the processing unit 130 encrypts the text string using the private key, and decrypts the encrypted text string using the public key stored in the modem device to obtain the decrypted text string.

In step S560, the processing unit 130 determines whether the character string is the same as the decrypted character string. If the text string is the same as the decrypted text string, it means that the private key is correct. Conversely, if the text string is different from the decrypted text string, it means that the public key and private key cannot be encrypted and decrypted normally, and the processing unit 130 executes step S580.

In step S570, the processing unit 130 determines that the private key is correct, indicating that all information in the device verification information is legal information, and ends the verification process.

It should be noted that, in other embodiments of the present disclosure, the program for verifying the correctness of the data may also be implemented by an independent program executable on the computer device. For example, the computer and the modem device 100 are directly connected in a wired manner, and an independent program is executed in the computer to detect the device verification information 122 in the modem. This disclosure is not limited to this.

In addition, since the reference verification information has been stored in the storage unit 120 of the present disclosure, the communication unit 100 does not need to be connected to the modem terminal system when the processing unit 130 executes the analog connection modem terminal system inspection instruction.

In summary, in the modem device and verification method disclosed in the present disclosure, since the modem device stores the reference verification information corresponding to the modem terminal system, the modem device will not be connected to the modem terminal system. Next, the device verification information of the modem device is verified by referring to the verification information. Based on this, the disclosed modem device and method for verifying data simplifies the method for verifying data and reduces the time consumed.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

100‧‧‧ modem device

110‧‧‧ communication unit

120‧‧‧Storage unit

122‧‧‧Reference Verification Information

124‧‧‧Device verification information

130‧‧‧processing unit

S210 ~ S220, S310 ~ S380, S410 ~ S480, S510 ~ S580‧‧‧Steps to verify the correctness of the data

FIG. 1 is a system architecture diagram of a modem device according to an embodiment of the disclosure. FIG. 2 is a flowchart of a method for verifying data according to an embodiment of the disclosure. FIG. 3 is a detailed flowchart of a method for verifying data according to an embodiment of the disclosure. FIG. 4 is a detailed flowchart of a method for verifying data according to another embodiment of the present disclosure. FIG. 5 is a detailed flowchart of a method for verifying data according to another embodiment of the present disclosure.

Claims (8)

A method for verifying data is applicable to a modem device. The method for verifying data includes: receiving an analog connection modem terminal system check instruction; and verifying whether a device verification information is legal according to a reference verification information, the reference verification Information and the device authentication information are stored in the modem device, and the reference authentication information includes the modem terminal system's certificate information, the reference root certificate, and the reference authorized device certificate. The device authentication information includes the root certificate, the authorized device certificate, and the data device. The certificate and the private key, wherein the step of verifying that the device verification information is legal according to the reference verification information includes comparing whether the reference root certificate is the same as each bit of the root certificate to determine whether the root certificate is legitimate ; When the root certificate is legal, compare whether the reference authorized device certificate and each bit of the authorized device certificate are the same to determine whether the authorized device certificate is legal. When the authorized device certificate is legal, according to the authorized device certificate Check whether the source of the data device certificate is legal and determine Whether the media access address of the data device certificate is the same as the media access address of the data device device to determine whether the data device certificate is legal; when the data device certificate is valid, determine the public key of the data device certificate and Whether the public key stored by the modem device is the same to determine whether the public key stored by the modem device is correct; when the public key stored by the modem device is correct, use the private key to encrypt a text string and use the The public key of the data device certificate decrypts the encrypted text string to obtain a decrypted text string; determines whether the text string is the same as the decrypted text string; and if the text string is the decrypted text string Same, judge that the private key is correct. The method for verifying data according to item 1 of the scope of patent application, wherein the reference verification information includes a reference root public key, and the device verification information includes a root public key, a manufacturer certificate, a data device certificate, and a private key. The step of referencing the verification information to verify that the verification information of the device is valid includes: comparing whether the reference root public key and each bit of the root public key are the same to determine whether the root public key is legal. When the root public key is legal , Verify whether the manufacturer's certificate is legal based on the root public key; when the manufacturer's certificate is legal, check whether the source of the data device certificate is legitimate according to the manufacturer certificate, and determine the media access address of the data device certificate and Whether the media device address of the modem device is the same to determine whether the data device certificate is legitimate; when the data device certificate is valid, determine whether the public key of the data device certificate is the same as the public key stored by the modem device, To determine whether the public key stored by the modem device is correct; when the public key stored by the modem device is correct, use the private key plus Encrypt a text string, and use the public key stored by the modem device to decrypt the encrypted text string to obtain a decrypted text string; determine whether the text string is the same as the decrypted text string; and if the text The string is the same as the decrypted text string, and it is determined that the private key is correct. The method for verifying data according to item 1 of the scope of patent application, wherein the reference verification information includes a reference root certificate and a reference public key, and the device verification information includes a root certificate, a manufacturer certificate, and a data device certificate. The verification information includes the steps of verifying that the verification information of the device is valid: comparing whether the reference root certificate is the same as each bit of the root certificate to determine whether the root certificate is valid; when the root certificate is valid, according to the reference The public key checks whether the source of the manufacturer's certificate is legitimate; when the manufacturer's certificate is legitimate, the data device certificate is judged to be legitimate based on the public key of the manufacturer certificate, and the media access address of the data device certificate and the Whether the media access address of the modem device is the same to determine whether the data device certificate is legal; and when the data device certificate is valid, determine whether the public key of the data device certificate is the same as the public key stored by the modem device, To determine whether the public key stored by the modem device is correct; when the public key stored by the modem device is When correct, use the private key to encrypt a text string, and use the public key stored in the modem device to decrypt the encrypted text string to obtain a decrypted text string; determine the text string and the decrypted text string Whether they are the same; if the text string is the same as the decrypted text string, it is judged that the private key is correct. The method for verifying data according to item 1 of the scope of patent application, wherein the modem device is not connected to the modem terminal system when verifying whether the device verification information is legal according to the analog connection modem terminal system check instruction. A modem device includes: a communication unit that receives and transmits signals; a storage unit that stores reference verification information and device verification information; and a processing unit that is coupled to the communication unit and the storage unit, and when the processing unit receives an analog connection Line modem terminal system check instruction, the processing unit verifies whether the device verification information is legal according to the reference verification information, wherein the reference verification information includes the certificate information of the modem terminal system, the reference root certificate, and the reference authorized device certificate, the device The authentication information includes a root certificate, an authorized device certificate, a data device certificate, and a private key. When the processing unit verifies that the device authentication information is valid according to the reference authentication information, the processing unit compares each of the reference root certificate with the root certificate. Whether a bit is the same to determine whether the root certificate is valid. When the root certificate is valid, the processing unit compares whether the reference authorized device certificate and each bit of the authorized device certificate are the same to determine the authorized device certificate. Whether it is legal when the authorized device certificate is legal The processing unit checks whether the source of the data device certificate is legitimate according to the authorized device certificate, and the processing unit determines whether the media access address of the data device certificate is the same as the media access address of the modem device to determine the Whether the data device certificate is valid. When the data device certificate is valid, the processing unit determines whether the public key of the data device certificate is the same as the public key stored by the data device device to determine whether the public key stored by the data device device is correct When the public key stored by the modem device is correct, the processing unit uses the private key to encrypt a text string, and uses the public key stored by the modem device to decrypt the encrypted text string to obtain a decrypted The processing unit determines whether the text string is the same as the decrypted text string. If the text string is the same as the decrypted text string, the processing unit determines that the private key is correct. The modem device according to item 5 of the scope of patent application, wherein the reference verification information includes a reference root public key, and the device verification information includes a root public key, a manufacturer certificate, a data device certificate, and a private key, where the processing unit When verifying that the device verification information is valid according to the reference verification information, the processing unit compares whether the reference root public key and each bit of the root public key are the same to determine whether the root certificate is legal; when the root certificate is legal , The processing unit judges whether the manufacturer's certificate is legal based on the root public key; when the manufacturer certificate is legitimate, the processing unit checks whether the source of the data device certificate is legitimate according to the manufacturer certificate, and the processing unit judges the data Whether the media access address of the device certificate is the same as the media access address of the modem device to determine whether the data device certificate is valid; when the data device certificate is valid, the processing unit determines the public key of the data device certificate Whether it is the same as the public key stored in the modem device to determine whether the public key stored in the modem device is correct; When the public key stored by the modem device is correct, the processing unit uses the private key to encrypt a text string, and uses the public key stored by the modem device to decrypt the encrypted text string to obtain a decrypted text The processing unit determines whether the text string is the same as the decrypted text string; if the text string is the same as the decrypted text string, the processing unit determines that the private key is correct. The modem device according to item 5 of the scope of patent application, wherein the reference verification information includes a reference root certificate and a reference public key, and the device verification information includes a root certificate, a manufacturer certificate, and a data device certificate, wherein when the processing unit is based on When the reference verification information verifies that the device verification information is valid, the processing unit compares whether the reference root certificate and each bit of the root certificate are the same to determine whether the root certificate is legal; when the root certificate is legal, the processing The unit checks whether the source of the manufacturer certificate is legal according to the reference public key; when the manufacturer certificate is legal, the processing unit judges whether the data device certificate is legal according to the public key of the manufacturer certificate, and the processing unit judges the data Whether the media access address of the device certificate is the same as the media access address of the modem device to determine whether the data device certificate is valid; when the data device certificate is valid, the processing unit determines the public key of the data device certificate Whether it is the same as the public key stored in the modem device to determine the public key stored in the modem device Whether the key is correct; when the public key stored by the modem device is correct, the processing unit uses the private key to encrypt a text string, and uses the public key stored by the modem device to decrypt the encrypted text string to obtain A decrypted text string; the processing unit determines whether the text string is the same as the decrypted text string; if the text string is the same as the decrypted text string, the processing unit determines that the private key is correct. The modem device according to item 5 of the scope of patent application, wherein the communication unit is not connected to the modem terminal system when the processing unit verifies whether the device verification information is legal according to the analog connection modem terminal system check instruction .