KR100416743B1 - A Method for Encryption of SMS Message - Google Patents

Abstract

In the method for transmitting a short message by using a mobile communication terminal,

In order to send a short message, when the character input is completed on the keypad and the transmission key is entered, the user is prompted to encrypt the message. If the message is not encrypted, the original message is transmitted. If the encryption message is entered, the encryption key is entered. Encrypting the short message and transmitting the encrypted key value, encrypting the message original text of the message, and transmitting the encrypted message,

When receiving this encrypted short message, selecting a decryption function, requesting a key input for decryption, and decrypting the cipher text only if the entered key value is the same as the key value used for encryption. A method of reading an encrypted short message received in a method comprising the step of displaying it as a readable character.

Description

Method of transmitting short message encryption and receiving decrypted message message {A Method for Encryption of SMS Message}

The present invention relates to a short message encryption transmission method and an encrypted message decryption reception method. When the sender encrypts and sends an encryption key to a specific receiver, the present invention relates to a method of decrypting and viewing the same key value.

Currently used mobile communication terminals include a RF unit for performing wireless transmission and reception, a microprocessor unit having an interface device for interfacing with a peripheral device, a flash ROM containing a program for operating a mobile phone, and a data to be stored. A memory module having an EEPROM SRAM, a keypad for entering numbers or letters, and an LCD as a display device are provided.

Such a terminal performs various functions. The terminal performs various functions such as confirming a location through continuous communication with a base station and sending and receiving a message from a short message service.

In a typical short service, a message (hereinafter simply referred to as a "short message") is sent unencrypted when sent over a data burst message on an access channel. When using a data burst message on a reverse traffic channel, it may be sent in an encrypted state, but its encryption is only determined by a channel assignment message sent by the base station, a handoff message, or a message encryption mode signal. The terminal itself cannot determine whether to encrypt it at the user's discretion. In other words, the messages appearing in the mobile communication terminal are displayed in a state that anyone can read.

The user of the mobile communication terminal may not always carry the terminal, and sometimes other people may see the terminal. If a message to keep a secret comes at this time, the information is exposed to the other person as a security problem. When a short message is received, the contents are displayed on the LCD window, and when the short service menu is entered, the entire text can be checked immediately, so the necessity of encryption is required. In particular, short messages that are not encrypted have a high risk of personal information leakage.

Unencrypted short messages may be intercepted and intercepted even in the radio wave state.In the case of receiving and sending short messages using a traffic channel, encryption is determined only by the base station's command regardless of the user's intention. Even if it is encrypted, there is a problem that anyone can easily see the original text unless the receiving terminal is currently locked. These problems come from the inability of the user to determine whether to encrypt directly.

It is an object of the present invention to provide a method for a receiver to decrypt and view an encrypted short message when the sender encrypts the short message to a specific receiver.

In order to achieve the above object, in the present invention, when an encryption key value is input at a keypad of a terminal to encrypt a short message, the transmitted message is simply encrypted, and the receiver receiving the encrypted message is transmitted. If a key value such as the encryption key value used in the message is entered, it is decrypted and displayed as a normal character, otherwise the character is broken and displayed as unreadable. Therefore, messages sent and received between specific users should not be exposed to the message sent and received to those who do not know the mutually agreed encryption key value.

1 and 2 are flowcharts for explaining the method of the present invention.

A method for encrypting a short message, comprising: a message sender generating a first random number, encrypting the generated first random number using a public key method, and transmitting the generated first random number to a key distribution center, and using the private key at the key distribution center. A first random number is obtained by decrypting a key-type encrypted random number, a second random number is generated at the key distribution center, the first random number and the second random number are calculated, and the symmetric key encryption is performed using the first random number. The message sender decrypts the cipher text into the first random number, obtains an operation value of the first random number and the second random number, connects the second random number generated by the key distribution center with the ID of the message receiver, and then decodes the first random number. 2 verify a random number, generate a session key for symmetric encryption using the ID, encrypt the session key, and send the message to the sender of the message; The sender to encrypt and then decodes the message and obtain a session key with the session key of plain text and sends it to the message center, be thought of a method consisting of transmitting the message to the message recipient from the message center, but complex to be blemish

According to the present invention, a method of encrypting a short message using a mobile communication terminal and transmitting the short message is a step of asking whether to encrypt the message when character input is completed on the keypad and a transmission key is input to send the short message. If it is input, the message original text is transmitted as it is, and if it is encrypted, inputting an encryption key, encrypting the encryption key value and the message text of the message, and transmitting the encrypted message.

The method for receiving the encrypted short message includes inputting a decryption function key if the received short message is marked as unreadable, requesting a key input for decryption, and when the input key value is encrypted. Only if the key value used is the same, the decryption of the ciphertext is performed.

The method will be described in detail with reference to the flowcharts of FIGS. 1 and 2.

As shown in FIG. 1, the method of encrypting a short message is to write a message to be sent using a keypad (step 100), and then press a transmission key (step 110), and encrypt or send it as a normal document. Is prompted in the menu (step 120). In this case, if the sender inputs that the user does not encrypt the data, the transmitter transmits the data in the normal mode (step 160). When the encryption key value is input, the key value and the user data which is the original message are added and encrypted (150). If the encryption key value is not input, go to step 120 and ask whether to encrypt (step 120). The encryption method uses a known encryption routine. When the encryption operation is finished, it is then transmitted (160).

This encrypted message is displayed in a state in which the characters on the receiving side are broken and unreadable.

When the receiver receives a message at the terminal (step 200), if the character is broken, the receiver knows that it is an encrypted sentence. As illustrated in FIG. 2, the receiver presses the decryption function key or selects the decryption function from the menu (210). step). This prompts the user to enter an encryption key (i.e. a decryption key) that is the same as the encryption key value, allowing the recipient to enter an encryption key as predetermined by the sender. If the value of the input encryption key is the same as the encryption key value transmitted in advance (step 220), the cipher text is decrypted and displayed (step 230).

At this time, if the receiver does not know the encryption key as predetermined by the sender and inputs another key, the ciphertext is not decrypted because the value of the input encryption key is different from the previously transmitted encryption key value.

It is even more convenient to add a step that allows you to choose whether to save a new read message.

The above operation is processed as a program by the microprocessor in the existing terminal device.

The encryption process uses various known algorithms. The key value selected for encryption is synthesized in the user data, and the key value is simply arithmetic (+,-, *, /) to the user data. You may also However, it is important to make the short message itself look like broken data after synthesis so that it can't be read without decryption process, and the receiver can use the same key value as synthesized by the sender.

As described above, the present invention can secure the security since the original message can be decrypted and read only when the receiver knows the encryption key value determined by the sender.

In the encryption of short message, the user can set the encryption and key value according to the user's intention, and the message received in broken form can not be read without knowing the key value sent from the sender. It is convenient for appointment of important short message transmission. In addition, it is necessary to enter the key value at the receiving end so that the original message content can be known. Therefore, when the terminal does not set the lock function or is lost, the received short message is leaked to others. In addition, since the SMC is not involved in the encryption process itself, and only the process of the terminal itself is added, the entire encryption system is easy to configure. This feature can not only be used as a means of encryption in short-selling services such as credit sales and e-commerce on the Internet, but also for young people and young lovers who enjoy sending and receiving certain users-for example, transacting business people, secret messages. It can be widely applied to layers.

Claims (4)

In the method for transmitting a short message by using a mobile communication terminal, To send a short message, when the character input is completed on the keypad and the transmission key is entered, the step of asking whether to encrypt the message, If the input is not encrypted, the original message is transmitted as it is, and if the input is encrypted, inputting an encryption key; Encrypting the encryption key value and the message text of the message; Transmitting the encrypted message. The method according to claim 1, And encrypting the key value and the user data using the key value in the encrypting step. In the method for receiving an encrypted short message using a mobile communication terminal, If the received short message is marked as unreadable, the recipient enters a decryption key value predetermined by the sender, A method of receiving an encrypted short message, comprising decrypting and displaying a decrypted character only when the input decryption key value is the same as the key value used when encrypting. The method according to claim 3, A method for receiving an encrypted short message, characterized in that in the step of decrypting an encrypted short message, the receiver decrypts the password by arithmetic operation with a decryption key value predetermined by the sender.