KR20080052092A - Method and apparatus for generating user secret key in mobile communication system - Google Patents

Abstract

A method and an apparatus for creating an user secret key in a mobile communication system are provided to create an user secret key which is a master key through a verified password algorithm and a secure mechanism in a mobile communication system of a third generation partnership project manner. A method and an apparatus for creating an user secret key in a mobile communication system includes a step of creating a key factor by inputting an operator secret key and a seed to a Hash function based on a block password(101). The created key factor is a key of algorithm of the block password. An input factor is created by operating the algorithm with an Output FeedBack mode by inputting user information for creating a user secret key into the algorithm of the block password(102). The created input factor is an input value of a keyed Hash function. The user secret key is created with the key factor which is the keyed Hash function(103).

Description

Method for generating user secret key in mobile communication system and device therefor {Method and Apparatus for generating user secret key in mobile communication system}

1 is a flowchart illustrating a method for generating a user secret key using a block cipher and a hash function based thereon in a mobile communication system according to an embodiment of the present invention.

2 is a diagram illustrating a process for generating a user secret key through a block encryption algorithm and a secure mechanism verified in a mobile communication system according to an embodiment of the present invention.

3 is a block diagram of a user secret key generation process in FIG. 2 according to an embodiment of the present invention.

4 is a block diagram of a device for generating a user secret key using a block cipher and a hash function based on the block cipher in a mobile communication system according to an embodiment of the present invention.

5 is a diagram for a block cipher based hash function for generating a user secret key according to an embodiment of the present invention.

6 is a diagram illustrating a keyed hash function of a RACE Integrity Primitives Evaluation-Message Authentication Code (RIPE-MAC) scheme according to an embodiment of the present invention.

7 is a diagram of a Boolean function for nonlinear compression conversion of an intermediate factor to generate a user secret key according to an embodiment of the present invention.

8 is a diagram for a function for linearly converting a key factor for generating a user secret key according to an embodiment of the present invention.

9 is a diagram illustrating a function of extending and converting user information for generating a user secret key according to an embodiment of the present invention.

10 is a block diagram showing in detail the method for generating a user secret key in FIG. 3 according to an embodiment of the present invention.

The present invention relates to a method for generating a user secret key in a mobile communication system and a device thereof, and more particularly, to a method for generating a user secret key, which is a master key, using a verified cryptographic algorithm and a secure mechanism in a 3GPP (3rd Generation Partnership Project) type mobile communication system. And to the apparatus.

The 3rd Generation Partnership Project (3GPP) is a standardization organization formed by the European and Japanese governments so that the asynchronous method can be determined by the standardization of International Mobile Telecommunication (IMT-2000). The present invention relates to a system that can generate a user private key that is simply guaranteed by changing and operating only an operator secret key and user information.

A user secret key used in a 3GPP mobile communication system refers to a secret key generated by a service provider and stored in a universal subscriber identity module (USIM) when a customer first joins a service. The user secret key serves as a master key and is used for authentication, and is used to generate confidentiality keys and integrity keys used to protect the confidentiality and integrity of user data and signal data. Since the safety of such a mobile communication system depends entirely on the safety of the user secret key, the safety of the user secret key generation algorithm is a very important factor.

However, in most communication systems, the generation method of the user secret key is rarely disclosed. This is because the operators of each system use the operator's secret key to generate the user's secret key as the operator's secret area and use a unique method for each operator without revealing the algorithm.

Therefore, each operator has a problem of securing an algorithm that maintains its own security, and when the stability of the collected algorithm is not guaranteed, there is a problem that the damage is passed on to the user.

The present invention provides a method and apparatus for generating a user secret key, which is a master key, through a verified cryptographic algorithm and a secure mechanism in a 3GPP (3rd Generation Partnership Project) -type mobile communication system. Regardless of the system, it is possible to create a user secret key with guaranteed password randomness and security using only the operator secret key and user information. The present invention utilizes a block cipher based hash function and a keyed hash function to satisfy randomness, one-wayness, high stability and improved performance. Generate a user secret key as input.

According to a preferred embodiment of the present invention for achieving the above technical problem, a method for generating a user secret key through a cryptographic algorithm and a secure mechanism verified in a mobile communication system includes an operator secret key and a seed, which is a random value, in a hash function based on a block cipher. Generating a key argument by inputting the generated key argument as a key of the algorithm of the block cipher, and using the information of a user who wants to generate a user secret key as input of the algorithm of the block cipher. Generating an input argument by operating in a FeedBack mode, and generating a user secret key using the generated input argument as an input value of a keyed hash function and using the key argument as a key of the keyed hash function. do.

In a preferred embodiment of the present invention for achieving the above technical problem, a user secret key generating apparatus through a cryptographic algorithm and a secure mechanism verified in a mobile communication system inputs an operator secret key and a random value seed into a hash function based on a block cipher. A key factor generation unit for generating a key factor, wherein the key factor generated in the key factor generator is a key of the algorithm of the block cipher, and information of a user who wants to generate a user secret key is input to the algorithm of the block cipher. Operating the algorithm in an output feedback (OFB) mode to generate an input argument, and the input argument generated by the input argument generator is an input value of a keyed hash function and the key argument is the keyed hash. Including a secret key generator that generates a user secret key as a function key It is made.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a method for generating a user secret key using a block cipher and a hash function based thereon in a mobile communication system according to an exemplary embodiment of the present invention.

This relates to a method for generating a user secret key. It is assumed that the user secret key generation algorithm of the present invention satisfies the following technical requirements.

(1) Randomness: The output of the user secret key generation algorithm of the present invention is indistinguishable from the output of a true random number generator. Therefore, an attacker cannot easily guess the user secret key.

(2) one-wayness: Even if the output of the user secret key generation algorithm is exposed, it is difficult to find the input part, because it is impossible to generate the secret key of the user when the secret key of the user is known. This is because the unidirectionality is maintained so that the input used for this purpose cannot be easily found. The user secret key generation algorithm of the present invention is an algorithm in which the unidirectionality is assumed as a systemized invention so that the used input cannot be easily found even when the output is exposed.

(3) High security: The security of the secret key generation algorithm depends on the security of the underlying cryptographic primitive. The user secret key generation algorithm of the present invention is designed based on a cryptographically strong primitive.

(4) Performance: Since the user secret key generation algorithm of the present invention is used only once when a user first joins, it does not significantly affect the performance of the system.

The present invention provides a method for generating a user secret key using a hash function and a keyed hash function based on a block cipher, and inputting an operator secret key, user information, and random information. It is possible to create a secure user private key by changing only the operator's private key and user information.

Referring to FIG. 1, in order to generate a user secret key, an operator secret key and a seed having a random value are first input to a block cipher-based hash function to generate a key argument (101), and the generated key argument is the block cipher. An input factor is generated by operating the algorithm in an OFB mode, using the information of a user who wants to generate a user secret key as the key of the algorithm of the block cipher.

Next, the generated input argument is used as an input value of a keyed hash function, and the user secret key is generated using the key argument as a key of the keyed hash function (103). Here, the block cipher is AES (Advanced Encryption Standard), and the mobile communication system is a 3GPP (3rd Generation Partnership Project) type mobile communication system.

In particular, in order to increase the stability, step 102 generates an encryption factor by performing an XOR operation on the generated key factor with an intermediate factor, which is a value obtained by compressing and converting the operator secret key and the random value seed together, and then converting the generated encryption factor. An input factor is generated by operating the OFB mode using the information of the user who is to be the key of the algorithm of the block cipher and the user secret key to be generated as the input of the algorithm. The key factor is a linearly transformed value, and the intermediate factor is a nonlinearly compressed value.

2 is a diagram illustrating a process for generating a user secret key through a block cipher algorithm and a secure mechanism verified in a mobile communication system according to an exemplary embodiment of the present invention.

2, first, input parameters usable in the user secret key generation algorithm of the mobile communication system are as follows.

(1) Operator's secret key: This uses key lengths as large as possible as an input that greatly affects the safety of the user's secret key generation algorithm. Use a key length of 256 bits.

(2) Random seed: A random input for the user secret key generation algorithm that collects and inputs 128-bit values from random samples such as date, time, screen information, and process information.

(3) User Information: Uses 56-bit IMSI (International Mobile Station Identity) assigned at the time of subscription as input by the user. Here, the user information, the International Mobile Station Identity (IMSI), is an international mobile station identification number and refers to a unique 15-digit identification number assigned to a mobile terminal when a global mobile communication system (GSM) service is subscribed. The number consists of a mobile country code, mobile network code, mobile subscriber identification number and national mobile subscriber identification number.

The user key generation algorithm processes the above inputs and outputs a 128-bit user secret key.

One embodiment of the present invention uses a block cipher, which is an encryption method in which an encryption key and an algorithm are applied on a data block basis to make a ciphertext so that identical blocks of plaintext are not identical ciphertext in one message. To do this, the ciphertext of the previous cipher block is applied to the next one in order.

In particular, the AES (Advanced Encryption Standard) block cipher is used as the encryption primitive that is the basis of the user secret key generation algorithm. The AES is currently used as a basic primitive because it has been analyzed in depth and safety, and is already used as a basic primitive of the MILENAGE algorithm for 3GPP's AKA protocol.

Of course, other block ciphers with the same input / output and key sizes as AES can be used. For convenience, all subsequent block ciphers use AES.

Referring to FIG. 2, the user secret key generation algorithm uses a 256-bit operator secret key (K), a 128-bit random seed (S), and 56-bit user information (I) as inputs, and then outputs 128 bits as outputs. Generates the user secret key of the bit.

 Enter 384 bits (K || S) into the AES-based hash function to get a 128-bit key factor (γ) (γ = Hash (K || S)). Next, using a nonlinear function (G), 384 bits (K || S) are reduced to 128-bit intermediate factors (α) (α = G (K || S)). After linearly transforming the key factor γ through a linear transformation function P (ρ = P (γ)), the cryptographic factor β is obtained by XORing the converted value ρ and the intermediate factor α. Calculate (β = α∀ρ).

Regarding the user information I, the value obtained by extending the 56-bit user information I to 128-bit value using the extension function F is applied as an initial value of the AES OFB (output feedback) mode and the key factor γ Is calculated as a key of the AES OFB mode (δ = AES _{OFB β} (F (I))). Finally, the 384-bit input factor δ is applied to the AES-based keyed hash function as the input and the 128-bit user secret key UK is calculated using the 128-bit key factor γ as the key (UK). = Keyed _{HASH γ} (δ)). Here, the OFB (output feedback) mode is a bit string encryption mode in which a block cipher has a dependency between blocks, and refers to a bit string encryption method that uses all of the output of the block cipher to update an input register.

3 is a block diagram of a user secret key generation process in FIG. 2 according to an embodiment of the present invention.

Referring to FIG. 3, it can be seen that the user secret key generation process of the present invention uses a block-based hash function and a keyed hash function as its basic components. It takes a 256-bit operator's secret key and a 128-bit random seed as input and processes it into a hash function and outputs a 128-bit random value (γ), which is used as a key in the keyed hash function and the block cipher OFB mode.

After expanding the 56-bit user information to 128 bits, it is set as the initial value of the block cipher OFB mode to obtain a 384-bit output δ, which is the input of the keyed hash function and the 128-bit The value γ is applied as a key of the keyed hash function to output a 128-bit user secret key (UK).

4 is a block diagram of an apparatus for generating a user secret key using a block cipher and a hash function based thereon in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, according to an embodiment of the present invention, the user secret key generation device 400 generates a key factor by generating an operator key by inputting an operator secret key and a random value seed into a hash function based on a block cipher. The key argument generated by the key factor generator 401 is used as the key of the algorithm of the block cipher, and information of a user who wants to generate a user secret key is input to the algorithm of the block cipher. An output argument generator 402 for generating an input argument by operating in an output feedback mode and the input argument generated by the input argument generator 402 as an input value of a keyed hash function, and the key argument as the keyed value. And a secret key generation unit 403 for generating a user secret key as a hash function key. Here, the block cipher is AES (Advanced Encryption Standard), and the mobile communication system is a 3GPP (3rd Generation Partnership Project) type mobile communication system.

In one embodiment, the operator secret key is 256 bits, the random value seed is 128 bits, the user information consists of 56 bits, and the generated user secret key consists of 128 bits. The key argument is also a 128-bit value and the input argument is a 384-bit value.

After all, in the 3GPP mobile communication system of the present invention, the user secret key generating device uses the operator secret key, random information, and user information as input values to generate the user secret key, a hash function, a keyed hash function, a nonlinear compression function, and a linear transformation. It can be said that the function structure includes the extension function, the OFB mode block cipher. In this regard, the input has been described in detail so far. Hereinafter, the functions will be described in detail.

The functions and their characteristics used in the user secret key generation algorithm are as follows.

(1) Hash Function: An embodiment of the present invention uses a hash function based on a block cipher, and AES is applied to the block cipher based on this. The result of the execution of the hash function γ = Hash (K || S) is used as a key of the keyed hash function, so that others cannot find the operator secret key and random seed from the user secret key. That is, since the operator secret key and the random seed value are not directly used in the keyed hash function, the values are more easily protected by not being easily found from the output of the user secret key algorithm.

Even if an attacker gets the γ from the user's private key, discovering Hash () 's preimage is computationally infeasible. This is because it takes about 2 ¹²⁸ operations to find the preimage for the 128-bit chain variable and 128-bit block cipher AES-based hash function used in the user secret key generation algorithm.

(2) Keyed Hash Function: The keyed hash function in the present invention is one-way (one-) which makes the input values γ and δ unknown from UK = Keyed _{HASH γ} (δ). provide wayness). This makes it impossible for an attacker to guess the user's private key (UK), and cannot calculate the UK without knowing both γ and δ. It is difficult to find γ even if we know δ and UK by accident, and it requires about 2 ¹²⁸ computations when the block cipher is ideal for attempting this. In addition, the computation amount of about ²⁶⁴ will be required to find a δ type, even if an attacker to know the γ and the UK.

(3) Function G: Function G in the present invention maintains unidirectionality using a nonlinear Boolean function. This makes the operator secret key K and the random seed S unknown from α through α = G (K || S). α is designed to hide the other when either β or γ is exposed.

(4) Function P: In the present invention, function P maps 128 bits (4 words W ₁ , W ₂ , W ₃ , W ₄ ) to 128 bits (4 words T ₁ , T ₂ , T ₃ , T ₄ ). It is a linear transformation. Various linear transformations are possible, and in particular, a function having good diffusion is intended as an embodiment of the present invention.

(5) Function F: In the present invention, the function F refers to a function of extending 56 bits (2 words W ₁ , W ₂ ) to 128 bits (4 words T ₁ , T ₂ , T ₃ , T ₄ ). This is to extend the number of bits to enter its initial value in the AES-based OFB mode encryption algorithm.

(6) Block cipher OFB mode (Block cipher_OFB): In the present invention, F (IMSI) is applied as an initial value, and AES is operated in OFB mode using β as a key so that an output of 384 bits δ = AES _{OFB β} (F (I Create)). This makes the user private key UK dependent on the user. This is for subscriber dependent UK. The generated 384-bit random output δ is the input value of the keyed hash function (three input blocks of the keyed hash function) which ensures the safety of the keyed hash function.

(7) β = α∀ P (γ): Through this, the key β (= α∀ P (γ)) applied to AES_OFB which is Block cipher_OFB in the present invention is different from γ. That is, the same value is not applied to the keys of the AES_OFB and keyed hash functions. This makes β unknown even if γ is known, and vice versa, even if β is known.

FIG. 5 illustrates a block cipher-based hash function for generating a user secret key according to an embodiment of the present invention.

This _{H i = E Hi -1 (X} i) ∀X i ∀H i , one of the configuration scheme of the block-based analysis password hash function Preneel as an example of the compression function of the hash function based on _{block-represents 1.} This shows an example that can be applied to the design principle of the present invention. The chain variable H _i of the compression function of the hash function and the length n of the output are 128 bits and the length l of the input block X _i is 128 bits. The initial value IV (H ₀ ) of the function assumes the following 128-bit value.

0x01234567 89ABCDEF FEDCBA98 76543210

In the compression function of the hash function, the input message length l is always fixed to 384 bits (256 bits K and 128 bits S) and does not padding.

FIG. 6 is a diagram illustrating a keyed hash function of a RACE Integrity Primitives Evaluation-Message Authentication Code (RIPE-MAC) scheme according to an embodiment of the present invention.

This is an example of a keyed hash function, which is a block diagram and a compression function of the RIPE-MAC scheme based on block ciphers. This embodiment is the length of a length n is 128-bits of output, and H chain variable _i as an example that can be applied to the design principles of the present invention, the input block X _i is 128 bits. Initial value H ₀ is set to 0x0000 ... 0000. The input message length of the keyed hash function is always fixed to 384 bits (384 bits output in AES OFB mode), and is not padded.

7 is a diagram of a Boolean function for nonlinear compression conversion of an intermediate factor to generate a user secret key according to an embodiment of the present invention.

This is one embodiment of the nonlinear compression function G. The function G compresses 384 bits (12 words W ₁ , ..., W ₁₂ ) into 128 bits (4 words T ₁ , T ₂ , T ₃ , T ₄ ). Represents a function. In addition to the above functions, other functions having nonlinearity can be used.

The four word values are T ₁ , T ₂ , T ₃ , T ₄ Is T ₁ = g (W ₁ , W ₅ ^{<< 3} , W ₉ ), T ₂ = g (W ₂ , W ₆ ^{<< 7} , W ₁₀ ) and T ₃ = g (W ₃ , W ₇ ^{<< 11} , W ₁₁ ), T ₄ = g (W ₄ , W ₈ ^{<< 13} , W ₁₂ ),

The function g is a Boolean function having the maximum nonlinearity 2 of a three-variable Boolean function that satisfies 0-1 balanced and SAC. (G (a, b, c) = ab ∨ac)

8 is a diagram for a function of linearly converting a key factor for generating a user secret key according to an embodiment of the present invention.

This is a function for linearly converting a 128-bit key factor to the same bit, and in one embodiment, a function that satisfies the equation PHT (a, b) = (2a + b, a + b). Here, the PHT is a pseudo-Hadamard transform and the variables a and b are word values to be subjected to a linear transformation. In addition to the above embodiment, other linear transformations having good diffusion properties may be used.

9 is a diagram illustrating a function of expanding and converting user information for generating a user secret key according to an embodiment of the present invention.

This represents one embodiment of function F that extends 56 bits (2 words W ₁ , W ₂ ) to 128 bits (4 words T ₁ , T ₂ , T ₃ , T ₄ ). To extend the number of bits, W ₁ and W ₂ can be converted into T ₁ and T ₃ , Use the method of associating with T ₂ and T ₄ and using the necessary external factors.

10 is a block diagram showing in detail the method for generating a user secret key in FIG. 3 according to an embodiment of the present invention.

This is a block diagram of a method for generating a user secret key by integrating the functions used in the user secret key generation algorithm. Functions on the block diagram may vary according to various function embodiments, and thus, various configurations may be possible in addition to FIG. 10.

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

Such a method and apparatus of the present invention has been described with reference to the embodiments shown in the drawings for clarity, but this is merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

In the 3GPP (3rd Generation Partnership Project) method of the present invention, a method and an apparatus for generating a user secret key, which is a master key, through a verified cryptographic algorithm and a secure mechanism, and the random number of the output when the user secret key is generated ( It is possible to ensure the security of cryptographic primitives according to the block ciphers which satisfy the randomness, one-wayness property and are based on. In particular, by configuring the mechanism so that the process of other steps before and after the specific step is exposed on the algorithm, the security and stability are further strengthened, and only the operator secret key and the user information are changed and used in the mobile communication system for high stability. Allows you to create a user private key. Since the user secret key generation algorithm operates only once when a user joins, there is little burden or restriction on the system performance, and the user secret key generation apparatus and method that is generalized and used in common are separate algorithms for each operator. To reduce the cost of developing and maintaining it.

Claims (19)

(a) generating a key argument by inputting an operator secret key and a seed having a random value to a block cipher-based hash function; (b) the generated key factor is used as the key of the algorithm of the block cipher, the information of a user who wants to generate a user secret key is input to the algorithm of the block cipher, and the algorithm is operated in an output feedback (OFB) mode. Generating an input factor; And (c) generating a user secret key using the generated input argument as an input value of a keyed hash function and using the key argument as a key of the keyed hash function. User secret key generation method using cryptographic algorithm and secure mechanism. The method of claim 1, Step (b) is (b-1) generating a cryptographic factor by performing an XOR operation on the generated key factor with an intermediate factor which is a value obtained by compressing and converting the operator secret key and a random value seed together; And (b-2) generating the input factor by operating in the OFB mode using the generated cryptographic factor as a key of the algorithm of the block cipher and using information of a user who wants to generate a user secret key as the input of the algorithm; Method for generating a user secret key through a cryptographic algorithm and a secure mechanism verified in a mobile communication system. The method of claim 2, In the step (b-1), the cryptographic algorithm and the secure mechanism are verified in the mobile communication system, wherein the cryptographic factor is generated by linearly converting the generated key factor and performing an XOR operation on the intermediate factor which is non-linearly compressed. How to create a user secret key. The method of claim 3, wherein The linear transformation of the key factor uses the following equation, and a method for generating a user secret key through a verified encryption algorithm and a secure mechanism in a mobile communication system Equation PHT (a, b) = (2a + b, a + b) Where PHT is a pseudo-Hadamard transform and the variables a and b are word values to be subjected to linear transformation. The method of claim 3, wherein The nonlinear compression transformation of the intermediate factor is transformed using a nonlinear Boolean function, The equation of the nonlinear Boolean function is g (a, b, c) = ab ∨ ￢ac (a, b, c is a word value that is subject to compression conversion) A method for generating a user secret key through a proven encryption algorithm and a secure mechanism in a mobile communication system. The method of claim 2, In the step (b-2), the user information that is the input of the algorithm is a value that is extended to the number of bits for the input of the algorithm through an extension function, the encryption algorithm and the secure mechanism verified in the mobile communication system How to create a user secret key. The method of claim 1, The block cipher is an AES (Advanced Encryption Standard), characterized in that the user's secret key generation method through a verified encryption algorithm and a secure mechanism in a mobile communication system. The method of claim 1, The operator secret key is 256 bits, the random value seed is 128 bits, the user information consists of 56 bits, and the generated user secret key consists of 128 bits. How to create a user secret key. The method of claim 8, The key argument is composed of 128 bits, and the input factor is composed of 384 bits, characterized in that the user secret key generation method through a verified encryption algorithm and a secure mechanism in a mobile communication system. The method of claim 1, The block cipher based hash function is one of Preneel's block cipher based hash functions. Mathematical expressions _{H i = E Hi -1 (X} i) ∀X i ∀H i -1 (H _i and X _i are the hash variable, which is a chain variable and an input block of the hash function, respectively, and the output length of the function is 128 bits). How to create. The method of claim 1, The keyed hash function is a hash function of a RACE Integrity Primitives Evaluation-Message Authentication Code (RIPE-MAC) technique based on the block cipher. . The method of claim 1, The mobile communication system is a 3GPP (3rd Generation Partnership Project) method of a mobile communication system, characterized in that the user's secret key generation method through a verified encryption algorithm and a secure mechanism. (a) a key argument generation unit for generating a key argument by inputting an operator secret key and a random value seed into a block cipher-based hash function; (b) outputting the OFB (Output FeedBack) using the key factor generated by the key factor generating unit as the key of the algorithm of the block cipher and using information of a user who wants to generate a user secret key as input of the algorithm of the block cipher. An input factor generator for generating an input factor by operating in a mode; And and (c) a secret key generator for generating a user secret key using the input argument generated by the input argument generator as an input value of a keyed hash function and the key argument as a key of the keyed hash function. A device for generating a user's secret key through a proven cryptographic algorithm and a secure mechanism in a mobile communication system. The method of claim 13, The input factor generator generates an encryption factor by performing an XOR operation on the key factor generated by the key factor generator with an intermediate factor which is a value obtained by compressing and converting the operator secret key and a random value seed together. In the mobile communication system, the generated encryption factor is the key of the algorithm of the block cipher and the information of the user who wants to generate a user secret key is input to the algorithm. A device for generating a user secret key through an encrypted encryption algorithm and a secure mechanism. The method of claim 14, And the input factor generator generates a cryptographic factor by linearly converting the key factor generated by the key factor generator and performing an XOR operation on the intermediate factor compressed and transformed into a nonlinear form. Device for generating user secret key through secure mechanism. The method of claim 13, The block cipher is an AES (Advanced Encryption Standard), characterized in that the user's secret key generation device through a verified encryption algorithm and a secure mechanism in a mobile communication system. The method of claim 13, The operator secret key is 256 bits, the random value seed is 128 bits, the user information is composed of 56 bits, and the generated user secret key is composed of 128 bits. Device for generating user secret key through mechanism. The method of claim 17, And a key factor of 128 bits and an input factor of 384 bits. The method of claim 13, The mobile communication system is a 3GPP (3rd Generation Partnership Project) mobile communication system, characterized in that the user's secret key generation apparatus through a cryptographic algorithm and a secure mechanism verified in the mobile communication system.

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