Short message safety communication method, system and device based on STK (SIM Tool Kit) business

[0031] Example one

[0032] figure 1 This is a flowchart of a method for secure SMS communication based on STK services provided by the first embodiment of the present invention, such as figure 1 As shown, the method specifically includes:

[0033] Step 11. Receive a plain text short message sent by the first mobile terminal;

[0034] Step 12. Encrypt the plain text short message according to the preset encryption key to obtain the encrypted short message;

[0035] Step 13. Return the encrypted short message to the first mobile terminal, so that the first mobile terminal can send the encrypted short message to the second mobile terminal corresponding to the second mobile terminal number, and the STK card of the second mobile terminal is sent according to the second mobile terminal The encrypted short message and the preset decryption key are decrypted to obtain the plain text short message, and the plain text short message is returned to the second mobile terminal.

[0036] In this embodiment, the first mobile terminal and the second mobile terminal may specifically be mobile phones. Meanwhile, the first mobile terminal specifically refers to the sending end of the short message, and the second mobile terminal specifically refers to the receiving end of the short message. Both the first mobile terminal and the second mobile terminal are provided with an STK card, that is, a SIM card with STK application and/or a SIM expansion card. The SIM expansion card is essentially a programmable IC card with a central processor inside. , Memory and STK application, the appearance is a contact conversion sheet designed according to the SIM card position of different mobile phones. When in use, align the chip contacts of the SIM card (the SIM card is a normal SIM card, or a SIM card with a built-in STK application) with the contacts on the SIM expansion card, stick the two closely together, and insert them together In the SIM card slot of the phone. When the mobile phone is turned on, the built-in application program not only does not change the original function of the mobile phone and the original number, but also provides the STK application built in the SIM expansion card to the mobile phone at the same time, thereby expanding the STK service of the mobile phone. In addition, if the service provider’s STK service is expanded or modified, a message can be sent to the mobile phone. The message is sent to the SIM expansion card through the mobile phone. The STK application of the SIM expansion card will use the message to update the existing built-in STK The application program is modified to update the STK business in time.

[0037] In this embodiment, taking the built-in SIM expansion card in the mobile phone to encrypt short messages as an example, the technical solution of the present invention is described in detail. The SIM expansion card of the first mobile terminal is preset with an encryption key, and the user passes through the first mobile terminal. Select the application for sending encrypted text messages in the STK menu, and enter the second mobile terminal number and text message content. The first mobile terminal then sends the text message content to the SMI extension card in the form of APDUs. The SIM extension card will The plain text short message is encrypted and brought to the encrypted short message; and the encrypted short message is returned to the first mobile terminal. It is worth mentioning that the SIM card with the STK application program can also realize the SMS encryption. The workflow of it is the same as that of the SIM expansion card, so I will not repeat it here.

[0038] In this embodiment, by receiving the plaintext short message sent by the first mobile terminal, encrypting the plaintext short message according to the preset encryption key to obtain the encrypted short message, and then returning the encrypted short message to the first mobile terminal for the first The mobile terminal sends the encrypted short message to the second mobile terminal corresponding to the second mobile terminal number. The STK card of the second mobile terminal decrypts the encrypted short message to obtain the plaintext according to the encrypted short message sent by the second mobile terminal and the preset decryption key. SMS, and then return the plain text SMS to the second mobile terminal, thereby effectively improving the reliability and security of the SMS.

[0039] It is worth noting that in step 12, the encryption key is the same as the decryption key, that is, the SIM expansion card of the first mobile terminal and the SIM expansion card of the second mobile terminal have the same key built in together. In this way, due to the use of the same key, while improving the security and reliability of the short message, it is also convenient for users to use.

[0040] Further, in step 12, the encryption key can also be a public key, and the decryption key can also be a private key. Specifically, the second mobile terminal generates two keys, and there is an interdependence relationship between the two keys: that is, if either key is used to encrypt information, the other key can only be used for decryption; the second mobile terminal If one of the keys is disclosed to the outside world, the public key is called the public key (that is, the encryption key described in the embodiment of the present invention); the other is set in the built-in SIM extension and is called the private key (that is, this The decryption key described in the embodiment of the invention). If the first mobile terminal sends an encrypted short message to the second mobile terminal, only the public key needs to be built in the SIM expansion card of the first mobile terminal. In this way, under the premise that the second mobile terminal safely saves the private key, only the private key built into the SIM expansion card of the second mobile terminal can decrypt the received encrypted short message, and other mobile terminals, including those sending encrypted short messages, cannot Decrypt the encrypted short message, thereby more effectively improving the security and reliability of the short message.

[0041] Example two

[0042] figure 2 This is a flowchart of a method for secure SMS communication based on STK services provided in the second embodiment of the present invention, such as figure 2 As shown, on the basis of the first embodiment above, in order to further improve the security and reliability of the short message, take the built-in SIM expansion card in the mobile terminal to encrypt the short message as an example to introduce the technical scheme of the present invention in detail. Step 11 is specific for:

[0043] Step 11. Receive a plain text short message carrying a destination number sent by the first mobile terminal;

[0044] Then step 12 specifically includes:

[0045] Step 121: According to the second mobile terminal number, obtain the encryption key corresponding to the second mobile terminal number from a preset mapping relationship table between the second mobile terminal number and the encryption key;

[0046] Step 122: According to the obtained encryption key, encrypt the plain text short message to obtain an encrypted short message.

[0047] In this embodiment, the first mobile terminal specifically refers to the sending end of the short message, and the second mobile terminal specifically refers to the receiving end of the short message. The SIM extension card of the first mobile terminal prestores the number of the second mobile terminal and the encryption key. In the mapping relationship table, the SIM expansion card of the second mobile terminal stores the decryption key in advance. Specifically, the SIM extension card of the first mobile terminal pre-stores the mapping relationship table between the second mobile terminal number and the encryption key. Specifically, each second mobile terminal number and the key or public key corresponding to each number, each second The SIM expansion card of the mobile terminal of the mobile phone correspondingly stores the respective secret key or private key in advance.

[0048] In this way, when the first mobile terminal sends short messages to different second mobile terminals of mobile phones, different keys can be used, thereby more effectively ensuring the security and reliability of the short messages.

[0049] It is worth mentioning that when the user needs to update the encryption key and/or decryption key, only the mobile terminal needs to use Over-the-Air Technology (hereinafter referred to as: OTA) to realize the The encryption key and/or decryption key are updated.

[0050] Example three

[0051] image 3 This is a flowchart of a method for secure SMS communication based on STK services provided in the third embodiment of the present invention. In this embodiment, the implementation of encrypted short message transmission through the SMS gateway platform is taken as an example to introduce the technical solutions of the present invention in detail, such as image 3 As shown, the method includes:

[0052] Step 31: Receive the first encrypted short message carrying the first mobile terminal number sent by the first mobile terminal, and the first decrypted short message includes the short message content and the second mobile terminal number;

[0053] Step 32: Obtain the corresponding decryption key according to the first mobile terminal number, decrypt the first encrypted short message, and obtain the content of the short message and the second mobile terminal number;

[0054] Step 33: Obtain the corresponding encryption key according to the second mobile terminal number, encrypt the content of the short message, obtain the second encrypted short message, and send the second encrypted short message to the second mobile terminal corresponding to the second mobile terminal number.

[0055] In this embodiment, each mobile terminal number and the encryption key and decryption key corresponding to the number are pre-stored in the short message gateway platform, so that the mobile terminal has higher security when sending encrypted short messages. It is worth noting that, in this embodiment, the first mobile terminal, the second mobile terminal, and the SMS gateway platform can either use symmetric encryption to encrypt the short messages, or use asymmetric encryption to encrypt the short messages. Specifically, the symmetric encryption method is that the encryption key preset in the SIM extension card of the first mobile terminal is the same as the decryption key corresponding to the first mobile terminal number in the SMS gateway platform; and the SIM extension card of the second mobile terminal is preset The decryption key of is the same as the encryption key corresponding to the second mobile terminal number in the SMS gateway platform. For the SIM extension card with the asymmetric encryption mode of the first mobile terminal, the encryption key is preset as the private key, and the decryption key corresponding to the first mobile terminal number in the SMS gateway platform is the public key; the SIM extension for the second mobile terminal The decryption key preset in the card is the private key, and the encryption key corresponding to the second mobile terminal number in the SMS gateway platform is the public key.

[0056] In this embodiment, taking the asymmetric encryption method as an example, the technical solution of the present invention is described in detail: the first private key of the first mobile terminal is preset in the SIM expansion card of the first mobile terminal (that is, as described in the embodiment of the present invention). The encryption key built into the SIM expansion card of the first mobile terminal), according to the first private key, encrypt the number of the second mobile terminal and the plain text short message sent by the first mobile terminal to obtain the first encrypted short message, and encrypt the first The short message is returned to the first mobile terminal. The first mobile terminal then sends the first encrypted short message carrying the number of the first mobile terminal to the short message gateway platform. The short message gateway platform obtains the first public key corresponding to the first mobile terminal number according to the first mobile terminal number query (that is, the decryption key corresponding to the first mobile terminal number of the short message gateway platform according to the embodiment of the present invention), and according to this The first public key decrypts the first encrypted short message to obtain the number of the second mobile terminal and the plain text short message. According to the second mobile terminal number query, the second public key corresponding to the second mobile terminal number (that is, the encryption key corresponding to the second mobile terminal number of the SMS gateway platform in the embodiment of the present invention) is obtained, and according to the second public key The public key encrypts the plain text short message, obtains the second encrypted short message, and then sends the second encrypted short message to the second mobile terminal corresponding to the second mobile terminal number. The second mobile terminal sends the second encrypted short message to the SIM expansion card of the second mobile terminal, and the SIM expansion card is based on the preset second private key (that is, the built-in SIM expansion card of the second mobile terminal in the embodiment of the present invention). The decryption key) decrypts the second encrypted short message, and displays the decrypted plain text short message to the second mobile terminal.

[0057] When the SMS gateway platform updates the encryption key and decryption key corresponding to a mobile terminal number, it only needs to send the updated encryption key and decryption key to the SIM expansion card of the mobile terminal via OTA to achieve this The SIM expansion card of the mobile terminal updates the encryption key and the decryption key, so that there is no need to notify all other users who apply for the SMS encryption service, and the security and reliability of the SMS are more effectively improved.