CN1264373C - Encrypting and de-encrypting method for personal hand-held communication system cell phone identification information - Google Patents

Abstract

The invention discloses a method for encrypting and decrypting authentication information of a mobile phone of a personal hand-held communication system, that is, a PHS mobile phone. The encryption method refers to a method of writing a number of the mobile phone, and the decryption method refers to an authentication method of the mobile phone. The method of writing a number includes: (1) The internal program of the mobile phone obtains the plain text of the authentication information; (2) The internal program of the mobile phone obtains the key from a specific storage area, and the key is the unique identification information corresponding to a certain hardware chip of the mobile phone; The encryption algorithm is used to encrypt the plaintext of the authentication information by the key to obtain the ciphertext of the authentication information; (4) storing the ciphertext of the authentication information in the memory of the mobile phone. Using the method proposed by the present invention fundamentally eliminates the way to obtain the key by copying, and achieves the purpose of protecting the authentication information of the PHS mobile phone, thereby effectively preventing the authentication information of the PHS mobile phone from being illegally obtained and preventing illegal access. The occurrence of the parallel machine phenomenon improves the system security performance of the PHS mobile phone and fully protects the interests of users and operators.

Description

Encryption and decryption method of mobile phone authentication information in personal handheld communication system

technical field

The invention relates to a PHS mobile phone, that is, a personal hand-held communication system mobile phone, in particular to a method for processing authentication information of the PHS mobile phone.

Background technique

Currently commercial mobile communication systems mainly include CDMA system, GSM system and PHS system. Correspondingly, there are three kinds of mobile terminals: CDMA mobile phone, GSM mobile phone and PHS mobile phone. Parallel usually refers to the situation where more than one mobile phone uses the same mobile phone number. Both CDMA mobile phones and GSM mobile phones use the machine-card separation technology to realize the confidential processing of mobile phone authentication information, which can effectively prevent the occurrence of parallel machines.

However, the currently used PHS mobile phones (commonly known as wireless access handsets, wireless local telephones or PHS) do not use machine-card separation technology, but use number writers to directly write sensitive data such as numbers and authentication information (Authentication Key) in plain text. Directly write to the mobile phone memory. A major hidden danger caused by this technical implementation method is that the technical threshold is relatively low, and it is easy to obtain confidential authentication information through illegal means. At present, there have been cases where the authentication information is read by using the terminal coding program, and the authentication information is obtained by forcibly reading all the contents of the EEPROM. If someone rewrites the obtained information on other PHS terminals, so that multiple users use the same user number, this will form an illegal parallel phenomenon, which will cause serious harm to real consumers and PHS network operators. a great loss. This technical defect is inherent in the design of the PHS mobile phone. An effective technical solution that can properly solve this problem has not been found in the current application, and no open technical literature for this specific technical problem has been found yet.

Contents of the invention

The technical problem to be solved by the present invention is to propose an encryption and decryption method for PHS mobile phone authentication information in view of the above-mentioned illegal paralleling of PHS mobile phones, which can effectively prevent illegal paralleling of PHS mobile phones and ensure the interests of consumers and operators .

The core idea of the present invention is: add a data encryption algorithm inside the PHS mobile phone, use the unique hardware identification information of the mobile phone itself as an encryption key, use the encryption algorithm to encrypt key authentication information, and save the ciphertext.

The technical solution of the present invention is achieved in the following way: a method for encrypting and decrypting authentication information of a PHS mobile phone, wherein the encryption method refers to a method for writing a number of a PHS mobile phone, and the decryption method refers to a method for obtaining authentication information by a PHS mobile phone, Described writing method comprises the following steps:

(1) The internal program of the mobile phone obtains the authentication information plaintext A _K from the number writing terminal;

(2) The internal program of the mobile phone obtains the key K _C from a specific storage area that cannot be accessed except the internal program of the mobile phone, and the key K _C is the unique identification information corresponding to a certain hardware chip of the mobile phone;

(3) Use the key K _C to encrypt the authentication information plaintext A _K using an encryption algorithm to obtain the authentication information ciphertext A _K ';

(4) storing the authentication information ciphertext A _K ' in the memory of the mobile phone;

The method for obtaining authentication information includes the following steps:

(1) The internal program of the mobile phone reads the authentication information ciphertext A _K ′ from the memory of the mobile phone;

(2) The internal program of the mobile phone obtains the key K _C from a specific storage area that cannot be accessed except by the internal program of the mobile phone;

(3) Use the key K _C to perform a corresponding decryption operation on the authentication information ciphertext A _K ' to obtain the authentication information plaintext A _K ;

(4) The plain text A _K of the authentication information is used in the normal authentication process of the mobile phone.

The above-mentioned key K _C cannot be changed by software. It can be the serial number of the baseband chip, which is stored in the internal ROM of the baseband chip. The mobile phone program does not provide an external access interface for the key K _C ; the key K _C can also be the CPU The serial number of the mobile phone or the serial number of the FLASH chip is stored in a storage area that is only allowed to be accessed by the internal program of the mobile phone.

The mobile phone memory mentioned above is the EEPROM or FLASH of the mobile phone, and the encryption algorithm is a symmetric encryption algorithm or an asymmetric encryption algorithm, such as a DES algorithm or an ADES algorithm or an IDEA algorithm or an NSSU algorithm.

The encryption and decryption method of PHS mobile phone authentication information proposed by the present invention encrypts the plaintext of authentication information by using a key stored in a specific area, and stores the ciphertext in the mobile phone memory; Decrypt to obtain the plain text of the authentication information for authentication. The key is stored in a specific area, and the mobile phone does not provide an external interface for accessing the key to ensure that the key is not leaked. This is completely different from EEPROM data that is easily read by the outside, and fundamentally eliminates the possibility of obtaining the key by copying. approach, to achieve the purpose of protecting the PHS mobile phone authentication information, thereby effectively preventing the PHS mobile phone authentication information from being illegally obtained, preventing the occurrence of illegal paralleling, improving the system security performance of the PHS mobile phone, and fully protecting users and operator's interests.

Description of drawings

FIG. 1 is a schematic diagram of a hardware structure of an existing PHS mobile phone.

2 and 3 are flowcharts of the method proposed by the present invention.

Wherein, FIG. 2 is a flowchart of a method for encrypting authentication information,

Fig. 3 is a flowchart of a method for decrypting authentication information.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

FIG. 1 is a schematic diagram of a hardware structure of an existing PHS mobile phone. As shown in Figure 1, the hardware structure of PHS mobile phone is divided into baseband part and radio frequency part. The baseband circuit is composed of the baseband chip BBIC as the core. The PHS mobile phone program is generally stored in the external memory, that is, stored on FLASH or ROM. The adjustable parameters of the PHS mobile phone are generally stored on the EEPROM. In the prior art, the PHS mobile phone program is in the During the manufacturing process, it is directly stored in ROM (read-only memory) or Flash (flash memory). When the mobile phone is used, the mobile phone program is loaded into SRAM and DRAM to run. The very important authentication information on the PHS mobile phone exists in the EEPROM in the form of original code plain text. When the authentication information needs to be used, the mobile phone program reads it from the storage area, and the storage area allows access by the external interface, and the stored data (including the authentication information) is easily obtained by the outside and leaked. The baseband part is connected to the outside through the IO interface, and can control the charging circuit to charge the battery. The battery supplies power to the regulated power supply LDO, and the regulated power supply LDO supplies power to the baseband chip and the radio frequency part. The baseband part receives calls through the microphone MIC, sends calls through the receiver RECEIVER, and sends ringing through the speaker BUZZER when a call comes. The radio frequency part modulates and demodulates the signal sent by the baseband part and sends it to the network system through the antenna. The display module LCD MODULE is used to display the interface information of the mobile phone, and the keyboard information is input to the baseband part for processing.

2 and 3 are flowcharts of the method proposed by the present invention. Fig. 2 is a flowchart of a method for encrypting authentication information, and Fig. 3 is a flowchart of a method for decrypting authentication information. As shown in Figure 2, the encryption method of authentication information, that is, the number writing method, includes the following steps: (1) The internal program of the mobile phone obtains the plaintext A _K of the authentication information from the number writing terminal. The authentication information plaintext A _K is input from the outside, generally through the number writing terminal, which is usually in the hands of the operator, and the number writing terminal writes the authentication information into the PHS mobile phone through the number writing software. (2) To obtain the key K _C , the internal program of the mobile phone obtains the key K _C from a specific storage area that is inaccessible except for the internal program of the mobile phone, and the key K _C is the unique identification information corresponding to a certain hardware chip of the mobile phone . In a preferred embodiment of the present invention, the key K _C is the serial number of the baseband chip, which is solidified and stored in the internal ROM of the baseband chip. The mobile phone program does not provide the external access interface of the key K _C , and the access of the key K _C It can only be done through the phone's internal program. The illegal access methods mentioned here except for the internal program of the mobile phone are mainly illegal copying of EEPROM, self-written driver programs to access memory space, etc. This is also the main technical means currently used by illegal parallel operators to obtain the plaintext of key information one. In the present invention, the key K _C can also be the serial number of the CPU or the serial number of the FLASH chip, which is stored in a storage area that is only allowed to be accessed by the internal program of the mobile phone. These unique identification information corresponding to the hardware chip cannot be rewritten by software, and are generally set at the factory. Usually, the data length of these identification information, that is, the key, is more than 8 bits, and the length can be the same on the same type of PHS mobile phone, and it can be changed appropriately for different models of mobile phones, and can be determined according to different situations. (3) Use the key K _C to encrypt the authentication information plaintext A _K using an encryption algorithm to obtain the authentication information ciphertext A _K ′. The encryption algorithm can be a symmetric encryption algorithm such as DES algorithm, ADES algorithm, IDEA algorithm or NSSU algorithm, etc., or an asymmetric encryption algorithm can be used. (4) Store the authentication information ciphertext A _K ′ in the memory of the mobile phone. The mobile phone memory here can be EEPROM or FLASH.

As shown in Figure 3, the decryption method of the present invention is the method that PHS mobile phone obtains authentication information and comprises the following steps: (1) mobile phone internal program reads authentication information ciphertext A _K ' from mobile phone memory. (2) The internal program of the mobile phone obtains the key K _C from a specific storage area that cannot be accessed except by the internal program of the mobile phone. This key is the key in Figure 2 above, which is taken out from a specific area, such as read from the internal ROM of the baseband chip. (3) Use the key K _C to perform corresponding decryption operations on the authentication information ciphertext A _K ′ to obtain the authentication information plaintext A _K . Decryption and encryption are a process of reverse operation, and the plaintext of the authentication information before decryption is obtained through the ciphertext and the key. (4) The plain text A _K of the authentication information is used in the normal authentication process of the mobile phone.

Using the method proposed by the present invention, even if all the data in a PHS mobile phone memory is copied to another mobile phone memory, this is equivalent to copying all the ciphertext information to another mobile phone, but according to the technical scheme proposed by the present invention , the original PHS mobile phone has unique and non-rewritable device information, that is, the key, which cannot be accessed through an external interface, and cannot be copied. In this way, since the key is unknown, the plaintext of the authentication information is also effectively protected. Even if it is copied to a PHS mobile phone of the same model, the correct plaintext of the authentication information cannot be obtained through its own key and the copied authentication information ciphertext, that is, illegal users cannot obtain the correct authentication information due to different keys. Authentication information, so as to effectively prevent illegal paralleling.

Claims (9)

1. An encryption and decryption method for authentication information of a mobile phone of a personal handheld communication system, characterized in that, the encryption method refers to a method for writing a number of a mobile phone of a personal handheld communication system, that is, a PHS mobile phone, and the decryption method refers to a method for writing the PHS mobile phone of the personal handheld communication system. A method for obtaining authentication information, the method for writing a number includes the following steps: (1) The internal program of the mobile phone obtains the authentication information plaintext A _K from the number writing terminal; (2) The internal program of the mobile phone obtains the key K _C from a specific storage area that cannot be accessed except the internal program of the mobile phone, and the key K _C is the unique identification information corresponding to a certain hardware chip of the mobile phone; (3) Use the key K _C to encrypt the authentication information plaintext A _K using an encryption algorithm to obtain the authentication information ciphertext A _K '; (4) storing the authentication information ciphertext A _K ' in the memory of the mobile phone; The method for obtaining authentication information includes the following steps: (1) The internal program of the mobile phone reads the authentication information ciphertext A _K ′ from the memory of the mobile phone; (2) The internal program of the mobile phone obtains the key K _C from a specific storage area that cannot be accessed except by the internal program of the mobile phone; (3) Use the key K _C to perform a corresponding decryption operation on the authentication information ciphertext A _K ' to obtain the authentication information plaintext A _K ; (4) The plain text A _K of the authentication information is used in the normal authentication process of the mobile phone. 2. The encryption and decryption method of mobile phone authentication information according to claim 1, characterized in that the key K _C is the serial number of the baseband chip, stored in the internal ROM of the baseband chip, and the mobile phone program does not provide the key K _C 's external access interface. 3. The encryption and decryption method of mobile phone authentication information according to claim 1, characterized in that said key K _C is the serial number of the CPU or the serial number of the FLASH chip, and is stored in a storage area that only allows the internal program of the mobile phone to access middle. 4. The encryption and decryption method of mobile phone authentication information according to claim 1, characterized in that said mobile phone memory is EEPROM or FLASH of the mobile phone. 5. The encryption and decryption method of mobile phone authentication information according to claim 1, characterized in that said encryption algorithm is a symmetric encryption algorithm. 6. The encryption and decryption method of mobile phone authentication information according to claim 5, characterized in that said symmetric encryption algorithm is DES algorithm or ADES algorithm or IDEA algorithm or NSSU algorithm. 7. The encryption and decryption method of mobile phone authentication information according to claim 1, characterized in that the unique identification information corresponding to a certain hardware chip of the mobile phone cannot be changed by software. 8. The encryption and decryption method of mobile phone authentication information according to claim 1, characterized in that the data length of the key K _C is more than 8 bits. 9. The encryption and decryption method for mobile phone authentication information according to claim 1, characterized in that said encryption algorithm is an asymmetric encryption algorithm.

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