KR20010009724A - Subscriber authentication method and ciphering session key generation method for security on wireless mobile communications network - Google Patents

Abstract

PURPOSE: A method for certifying a subscriber in a radio mobile communications net and a method for generating an encoding session key are provided to supply an algorithm generating an early encoding session key for protecting the algorithm certifying a mobile subscriber and sending data. CONSTITUTION: A method for certifying a subscriber in a radio mobile communications net and a method for generating an encoding session key include a few steps. In the first step the random value(20) of 128 bits and the mobile subscriber's secret certifying key of 64 bits are prepared. In the second step the random value(20) of 128 bits is divided by 64 bits and the value is input to each 16 round F function(21,23), a component of a new mobile subscriber certifying algorithm. In the third step the output stream of 64 bits through operation of F function is generated and is prepared as a key of the second part F function(23). In the fourth step the second part F function(23) inputs the random value of 64 bits and the output stream of the 64 bits and generates the output stream of 64 bits. In the fifth step the output stream of the 64 bits of the second part F function(23) is calculated by exclusive-OR(22) of the random value of 64 bits and the bit unit and the value is divided by 32 bits(25,26) and is calculated by exclusive-OR(24) of the bit unit and 32 bits, the final key stream(28) are generated.

Description

Subscriber authentication method and ciphering session key generation method for security on wireless mobile communications network}

The present invention relates to a new subscriber authentication method and an initial encryption session key generation method proposed for authentication of mobile subscribers and encryption of transmission data and signals in consideration of security in a wireless mobile communication network.

The present invention relates to matters related to subscriber authentication and data encryption for transmitting data and signal protection, which should be considered in terms of safety in a wireless mobile communication network. Conventional techniques related to this include authentication and encryption schemes in wireless mobile communication systems based on IS-41 in the United States, and authentication and protection schemes based on GSM systems in Europe.

In the United States, CAVE (Cellular Authentication and Voice Encryption Algorithm) and Shared Secret Data (SSD) algorithms are used as authentication algorithms and initial session key generation algorithms for encryption in wireless networks. In Europe, A3 (COMP128) and A8 (variant COMP128) are used respectively. These algorithms are basically based on secret-key algorithms, but since these algorithms are analyzed so much that they have many vulnerabilities, they are being suspended and improved accordingly.

The most serious threats to information in next-generation digital mobile networks are illegal tampering, eavesdropping, identity disguise, and retransmission. Against these threats, the authentication service, along with the confidentiality and integrity services, is one of the most important information protection services. In particular, authentication is an important service that can protect against identity spoofing and retransmission threats and can be used in various forms in conjunction with access control, data integrity, confidentiality, denial of containment, and audit services. In particular, digital mobile communication such as digital cellular mobile communication and personal mobile communication has the convenience of providing voice and data services regardless of time and place, while using eavesdropping as a communication medium, eavesdropping, radio recording and illegal There is a problem that the possibility of toll fraud by duplication increases. Such toll fraud is directly related to toll collection, leading to reduced profits and distrust in the provision of services.

Disclosure of Invention The present invention has been made to solve the above-mentioned problems of the prior art. The present invention provides a mobile subscriber authentication algorithm and transmission data to enable more reliable and stable mobile subscriber authentication and transmission signal and data protection in a wireless mobile communication network environment. An initial encryption session key generation algorithm is provided for protection.

1 is a block diagram of a digital mobile communication system to which the present invention is applied;

2 is a structural diagram of a subscriber authentication algorithm according to an embodiment of the present invention;

3 is a structural diagram of an encryption session key key generation algorithm according to an embodiment of the present invention;

4 is a flowchart illustrating an operation of a subscriber authentication method and an encryption session key generation method in a wireless mobile communication network according to an embodiment of the present invention.

※ Explanation of code about main part of drawing ※

11: wireless access network 12: infrastructure

111: mobile terminal 112: smart card

112: base station 114: mobile switching center

115: location register 116: authentication center

A subscriber authentication method in a wireless mobile communication network for achieving the above object comprises the steps of preparing a 128-bit random value and a 64-bit mobile subscriber secret authentication key as an input of a mobile subscriber authentication algorithm; A 64-bit output stream is generated by the operation of the front-end F function, which is divided into two 64-bit random values into two 16-round F functions, which are components of the new mobile subscriber authentication algorithm. In the third step of preparing, the rear end F function receives a 64-bit random value and an output stream of the front end F function as inputs, and generates a 64-bit output stream. After the exclusive OR of the random value of the bit and the bit unit, the 32 key bits are divided again, and the exclusive OR of the bit unit is performed again, and the final keystream 32 bit A fifth step of generating a.

In addition, the method for generating an encrypted session key in a wireless mobile communication network according to the present invention comprises preparing a 128-bit random value and a 32/64 / 128-bit selective secret key input to four F functions to generate an initial encrypted session key. A first step of doing; The second step of generating a 64-bit key stream by inputting a random value of 64 bits and an optional secret key of 32/64/128 bits into two front-end F functions, and then providing them to the two back-end F functions, respectively. ; Of the two subsequent F functions, the left side F function generates a 64-bit output stream using a 64-bit key stream and an optional secret key. A third step of inputting; The F function on the right side of the rear stage generates a 64-bit output key stream using the 64-bit key stream and the output value of the F function on the left side of the rear stage. And a fourth step of generating a session key value.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a configuration diagram of a general mobile communication system including an authentication center and a mobile terminal to which the present invention is applied, which is mainly composed of a radio access network 11 and a core network 12. do. The wireless access network 11 includes a mobile terminal 111, a smart card 112, and a base station 113. The base network 12 also includes a Mobile Switching Center 114, a Home / Visited Location Register 115, and an Authentication Center 116.

Referring to FIG. 1, when a mobile subscriber registers a service, the authentication center 116 in the base network 12 processes a service registration and simultaneously issues a smart card 112 containing an authentication and encryption algorithm to the subscriber. Through the issued smart card 112, the mobile subscriber connects his smart card 112 to the mobile terminal 111 in the wireless access network 11 and receives identification and authentication from the network before receiving a communication service.

In addition, since the mobile subscriber also attempts to authenticate the network based on the encryption algorithm and parameters included in the smart card 112, the mobile subscriber can protect the exposure of his / her secret information. At this time, the mobile station 111 and the base station 113 is a wireless section, and can be transmitted by encrypting a signal or a message. After this process, the calling party subscriber may perform the secret communication between mobile subscribers by distributing session key for secret communication with the called party subscriber.

2 is a structural diagram of a mobile subscriber authentication algorithm according to an embodiment of the present invention, which is composed of two 16 round Feistel (F) functions 21 and 23. First, the input 128-bit random value 20 is divided into 64 bits left and right and input to two F functions 21 and 23. The F function 21 of the double front end receives the 64 bits of the left side and the 32 bits of the subscriber secret key (Ki) to generate a 64-bit output stream, which is a 64-bit random value and an exclusive OR of bits. 22 to generate a 64-bit output key stream. This value is again prepared as a key of the later F function 23.

The rear F function 23 receives the 64-bits on the right side and the F-function output key streams on the front side, and generates a 64-bit output stream. Create an output stream of bits. The 64 bits of the output stream of the subsequent F function 23 are divided by 32 bits (25, 26), and the final 32-bit key stream 28 is generated through the bitwise operation of the nonlinear function exclusive logical element 27. This value allows the mobile subscriber to be authenticated as a valid subscriber.

3 is a structural diagram 31 of an initial encryption session key generation algorithm according to an embodiment of the present invention in connection with FIGS. It consists largely of four 16 round Feistel functions (F functions) (31, 32, 33, 34). First of all, the two F functions 31 and 32 divide the input 128-bit random value 35 into 64 bits to the left and right, and simultaneously accept the subscriber secret key (Ki) value and output the 64-bit output key stream ( 36).

Prepare this again with the input of the other two 16 round Feistel functions (33, 34). The double front-end F function 33 receives the subscriber secret key (Ki) value again to generate a 64-bit output stream, which is the logical bitwise exclusive of the 64-bit output on the left of the first two F functions (31,32). (37), and input with the key of the following F function 34. The rear F function 34 receives the 64-bit output on the right side of the first two F functions 31 and 32 and the output stream of the front F function 33 as key values, and generates a 64-bit output stream. A bitwise exclusive OR 38 with the input of the F function 34 generates the final 64-bit initial encryption session key 39.

4 is a flowchart illustrating a subscriber authentication method and an encryption session key generation method in a wireless mobile communication network according to an embodiment of the present invention.

First, the operation flow of the mobile subscriber authentication method will be described.

First, a 128-bit random value and a 64-bit mobile subscriber secret authentication key are prepared as inputs to the mobile subscriber authentication algorithm. Next, the 128-bit random value is divided by 64 bits and input to each of the two 16 round F functions, which are components of the new mobile subscriber authentication algorithm. Next, the operation of the front end F function is used to generate a 64-bit output stream and prepare it as the rear end F function key. Next, the latter F function receives a 64-bit random value and an output stream of the preceding F function as inputs, and generates a 64-bit output stream. The 64-bit output stream of the F function 64 bits is then exclusive-ORed in units of bits and a random value of 64-bits, and then divided into 32-bits in order to generate exclusive final bits of 32-bits.

Next, an operation flow of the initial encryption session key generation method will be described.

First, a 128-bit random value and 32/64 / 128-bit optional secret key input to four F functions are prepared for initial encryption session key generation. 64 bits of random values and 32/64/128 bits of optional secret key are inputted to two F functions, and 64 bits of key streams are generated at the same time and provided to two subsequent F functions.

Next, input each 64-bit key stream into the remaining two trailing F functions. At this time, the F function on the left side of the two subsequent F functions generates a 64-bit output stream using a 64-bit key stream and an optional secret key, and combines the input value again and bitwise exclusively into the F function on the right. Enter it.

The F function on the right side of the rear stage generates a 64-bit output stream again by using the 64-bit input value provided from the front end F function and the output value of the F function on the left side of the rear stage. Generates a 64-bit initial encrypted session key value.

While the invention has been described above based on the preferred embodiments thereof, these embodiments are intended to illustrate rather than limit the invention. It will be apparent to those skilled in the art that various changes, modifications, or adjustments to the above embodiments can be made without departing from the spirit of the invention. Therefore, the protection scope of the present invention will be limited only by the appended claims, and should be construed as including all such changes, modifications or adjustments.

According to the present invention as described above, the following effects can be expected.

First, because wireless mobile communication network provides more secure and reliable authentication function, it can prevent fraudulent use of mobile terminal through more reliable authentication from mobile operator's point of view, thereby reducing operator's profits and safer from subscriber's point of view. And reliable mobile communication services can be provided.

Second, the development of a new encryption initial session key generation algorithm prevents the exposure of mobile subscriber secret information in a wireless mobile communication network, thereby enabling privacy protection for mobile subscribers.

Third, since a subscriber authentication algorithm providing a more secure and reliable authentication function and an initial encryption session key generation algorithm for transmission data protection are provided in a wireless mobile communication network, it is possible to secure an independent technology for core technology development. Therefore, the technology fee for the use of foreign technology can be prevented, and the technological competitiveness can be induced for the establishment of the base technology development and core technology development.

Fourth, in addition to the above effects from the mobile subscriber's point of view, the necessary information and subscriber authentication algorithm is implemented in a smart card that can be mounted on the mobile terminal, so it is practically easy to implement, and this may not be limited to the mobile terminal. It is also easy to provide, economical in use, safety, reliability and utility.

Claims (2)

A first step of preparing a 128-bit random value and a 64-bit mobile subscriber secret authentication key as input to the mobile subscriber authentication algorithm; A second step of dividing the random value of the 128 bits by 64 bits and inputting them into two 16 round F functions that are components of a new mobile subscriber authentication algorithm; A third step of generating a 64-bit output stream through operation of the front end F function and preparing it as a rear end F function key; The fourth stage F function receives a 64-bit random value and an output stream of the preceding F function as inputs, and generates a 64-bit output stream. A fifth step of generating the final key stream 32 bits by dividing the output stream of the 64-bit F function 64-bit by the 64-bit random value and the bit unit exclusively, and then dividing the 32-bit by exclusive bit unit once again. Subscriber authentication method in a wireless mobile communication network comprising a. A first step of preparing a 128-bit random value and a 32/64 / 128-bit selective secret key input to four F functions for initial encryption session key generation; The second step of generating a 64-bit key stream by inputting a random value of 64 bits and an optional secret key of 32/64/128 bits into two front-end F functions, and then providing them to the two back-end F functions, respectively. ; Of the two subsequent F functions, the left side F function generates a 64-bit output stream using a 64-bit key stream and an optional secret key. A third step of inputting; The F function on the right side of the rear stage generates a 64-bit output key stream using the 64-bit key stream and the output value of the F function on the left side of the rear stage. And a fourth step of generating a session key value.