JPH11109855A - Enciphering device and enciphering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an encipherment method which can encipher without requiring high precision arithmetic operation capability, is highly reliable and which application can be easily added and altered. SOLUTION: An enciphering key consisting of a secret key and a public key is stored in security devices 12a, 12b. When communicating a cipher from PC11a to PC11b, a main program on PC11a passes the control onto a subprogram on the security device 12a. The subprogram sequentially generates a vector defined in an n-dimensional closed spatial region according to the ciphering key, and generates a cipher data by performing logical operation of original data and the vector generated above in each bit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encryption device used in, for example, a system for performing cryptographic communication, and more particularly to an encryption device and an encryption method for encrypting original data using a multidimensional vector.

[0002]

2. Description of the Related Art In an information system such as a computer and a network, in an environment where an unspecified number of users use it, eavesdropping or falsification of information by a malicious user has become a serious problem. In many cases, encryption technology is used.

As a technique generally known as an encryption technique, the technique disclosed in the following document is detailed. Reference "Communications of the
ACM Vol. 21, No. 2 (1978) p12
0. A Method for Obtaining
Digital Signatures and Pu
Brick-KeyCryptosystems: R.
L. Rivest, A .; Shamir, and L.M. A
dleman, MIT Laboratory for
Computer Science and Depa
rtment of Mathmatics. The encryption technique disclosed in this document has been accepted by the public as fairly strong, and RSA (Rivest-S
hamir-Adleman) method. In addition, a method derived from the RSA method has been developed as a “famous” authentication means in electronic commerce and is being put to practical use.

[0004] The RSA method is a public key (asymmetric) cryptosystem utilizing the difficulty of factorization, and the remainder (remainder) obtained by dividing the result of raising the data to a large integer is used as a ciphertext. The feature of this RSA method is that two prime numbers (p and q)
It is difficult to find the original two prime numbers from the product of p and q, even if the product of the two prime numbers is known.
Furthermore, it is difficult to estimate the decryption operation.

[0005]

The above-mentioned RSA method itself is practical as such, and the reliability is guaranteed to be considerably high when the bit length of the data as the encryption key is sufficient. Have been. In order to ensure this reliability, it is currently the mainstream to use 256-bit encryption key data, but this is sometimes too short,
Further, the necessity of an encryption key having a data length of 512 bits or 1024 bits is discussed.

However, since the data length is practically limited by the calculation accuracy and the calculation speed of the computer, it is not always advisable to increase the bit length excessively in the long term.

That is, the RSA method and the encryption method derived from the RSA method have a problem that the reliability is restricted by the performance of the computer. There is also a problem that a significant change is required for a reliability test or the like of the authentication system due to a change in the bit length of the encryption key.

The present invention has been made in view of the above points, and it is possible to perform encryption without requiring high-precision arithmetic capability, and it is highly reliable, and it is easy to add or change an application. It is an object of the present invention to provide an encryption device and an encryption method that can realize encryption.

[0009]

The encryption device of the present invention comprises:
Original data acquisition means for acquiring original data to be encrypted; vector generation means for sequentially generating vectors defined in a closed region of an n-dimensional (n ≧ 1) space;
A logical operation unit that performs a logical operation of the original text data obtained by the original text acquisition unit and a component of the vector generated by the vector generation unit on a bit-by-bit basis to generate ciphertext data. .

According to such a configuration, vectors defined in a closed region of an n (n ≧ 1) -dimensional space are sequentially generated, and the original text data to be encrypted and the components of the vector are , Ciphertext data is generated.

As described above, by encrypting the original text data with the elements of the multi-dimensional vector, the encryption can be performed without requiring a high-precision operation capability such as the RSA method. High, adding applications,
Encryption that can be easily changed can be realized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The present invention relates to an encryption process in a case where a group of people carries out data communication with a common security device (encryption device).

FIG. 1 is a conceptual diagram showing the configuration of a system for performing cryptographic communication. In the figure, reference numerals 11a and 11b denote personal computers (hereinafter, referred to as PCs), and reference numerals 12a and 12b denote security devices. Here, data communication is performed between the PC 11a owned by the user A and the PC 11b owned by the user B. I assume.

The PCs 11a and 11b are general-purpose computers and have security devices 12a and 12b, respectively.
Connection is possible. Security device 12a, 1
2b is composed of an IC card. Some information is written in the security devices 12a and 12b at the time of shipment from the factory. The information to some extent is the information on the serial number of the IC card, the user ID of each member of the group, and the encryption keys (secret keys P ₁ and P ₂ ).
This information is common to each member of the group and is not disclosed.

FIG. 2 is a block diagram showing a circuit configuration of the PC 11a and the security device 12a. The same applies to the configurations of the PC 11b and the security device 12b.

The PC 11a comprises a general-purpose computer,
It has a CPU 21 and executes data processing by activating a main program. A storage device 22, a RAM 23, a keyboard 24, a display unit 25, and a card I / F (interface) 26 are connected to the CPU 21 via a system bus.

The storage device 22 is composed of, for example, a hard disk device, a floppy disk device, a CD-ROM device, etc., and stores various data, programs, etc. Here, original data to be encrypted, Authentication file to be stored. In addition, a program stored in a recording medium (such as a disk) is installed in the storage device 22. The CPU 21 reads the program installed in the storage device 22 and executes processing according to the program.

The RAM 23 functions as a main memory of the apparatus and stores various data necessary for processing of the apparatus. The keyboard 24 is an input device for inputting data and instructing various functions. The display unit 25 is, for example, a CRT (Cathode Ray Tube) or an LCD.
(Liquid Crystal Display), etc., for displaying data.

The card I / F 26 has a connector 27
The security device 12a is connected via the security device 12a, and data input / output control is performed with the security device 12a.

On the other hand, the security device 12a is an IC
It comprises a card, has a CPU 31, and executes data processing by activating a sub-program. In this CPU 31,
The ROM 32, the RAM 33, and the flash memory 36 are connected via a system bus.

The security device 1 is stored in the ROM 32.
A sub-program for realizing the function as 2a is stored. The RAM 33 stores the security device 12a
Here, an input buffer 34 for temporarily storing data transmitted from the PC 11a, and an output buffer for temporarily storing data to be transmitted to the PC 11a. 35.

The flash memory 36 is used as a storage device for storing the database 41 shown in FIG. As shown in FIG. 3, this database 41
Each member includes the above-mentioned information common to each member (non-public information) and information unique to each member (public information). The information common to each member (non-public information) is a serial number, a user ID of each member of the group, and encryption key data (secret keys P ₁ and P ₂ ). The information (public information) unique to each member is the encryption key data (public keys P ₃ , P
₄ ) and password. The password is used as a part of the public key.

The connector 37 is for electrically connecting the security device 12a to the PC 11a. Here, the operation in the case of performing the cryptographic communication in the system of FIG. 1 will be briefly described.

First, security devices 12a and 12b used as IC cards are delivered to each member of the group. The security device 12a, the database 41 is provided in 12b, to its database 41, pre-production number, the user ID of each member of the group, the encrypted key data (private key P _1, P ₂₎ is registered ing.

Each member writes an encryption key (public keys P ₃ and P ₄ ) and a password into the security devices 12a and 12b. The information written here is stored in the public part of the database 41.

Here, for example, from PC 11a to PC 11b
When encrypted communication is performed on each member (users A and B)
Connects the security devices 12a and 12b to the PC 11a,
11b for encryption. in this case,
In the present invention, the encryption algorithm is based on vector generation described later.

At this time, a function for generating a vector or a constant to be used is converted into an encryption key (secret / public key).
Determined by The encrypted document is sent to the other party together with the public key. The receiving side decrypts the encrypted document with the received public key and its own private key.

Next, the operation of the embodiment will be described. Here, paying attention to the PC 11a and the security device 12a shown in FIG. 1, the respective processing operations will be described in two modes of (a) user registration and (b) data encryption.

(A) User Registration First, the user performs user registration when performing encrypted communication using the security device 12a. This means that the member who has received the security device 12a (IC card) registers information relating to the disclosed portion of FIG. 3 in his / her PC 11a.

FIGS. 4A and 4B show PCs at the time of user registration.
11 is a flowchart illustrating processing operations of the security device 11a and the security device 12a. The user inputs user authentication data to the PC 11a through the main program on the PC 11a (step A11). In this case, the user authentication data is a user ID. The main program transfers the user ID input here to the input buffer 34 of the security device 12a (Step A12). Then, control is passed to the sub-program on the security device 12a.

On the security device 12a side, when the subprogram confirms that data exists in the input buffer 34, it reads it (step B11). Then, the sub-program accesses the flash memory 36 on the security device 12a and checks whether or not the user ID input as the user authentication data is registered in the database 41 provided in the flash memory 36. (Step B12).

As a result, if the user ID is not registered in the database 41 (N in step B12)
o), it is determined that the user is not a member of the group, and the subsequent processing is interrupted (step B13).

On the other hand, the user ID is stored in the database 41.
Is registered (Yes in step B12)
s) The user is determined to be a member of the group, and a request for a password and an encryption key (public key) is made to the PC 11a (step B14).

The user inputs a password and an encryption key (public key) according to this request (step A1).
3). The main program on the PC 11a transfers the password and the encryption key (public key) input here to the input buffer 34 of the security device 12a (Step A14). The password is used as a part of the public key.

As described above, when the password and the encryption key (public key) are input by the user who has been recognized as a group member, the security device 12a
The sub-program reads the input information, encrypts the information if necessary, and writes it in the public part of the database 41 provided in the flash memory 36 (step B15).

At this point, the mathematical function used by the user for encryption is determined. The constants used in this mathematical function are fixed. Note that the present invention is characterized in that a multidimensional vector is used as the mathematical function, which will be described later.

After the information processing, the subprogram creates a report of the database 41 (step B1).
6) After storing this in the output buffer 35 on the security device 12a, control is passed to the main program on the PC 11a (step B17).

Here, data used by the main program for user authentication is encrypted and written in the report. On the PC 11a side, the main program confirms that there is data in the output buffer 35 on the security device 12a, reads the data, and reads the data.
2 as file data (step A1).
5). The file data written here becomes an authentication file, which is used for user authentication when performing subsequent encrypted communication (step A16).

(B) Data encryption The data encryption referred to here means that a created document is actually encrypted and transmitted.

FIGS. 5 (a) and 5 (b) show the Ps at the time of data encryption.
It is a flowchart which shows the processing operation of C11a and the security device 12a. The user enters his / her user ID and password with the security device 12a (IC card) attached to the PC 11a (step C11). By inputting the user ID and the password, the main program on the PC 11a performs user authentication with reference to the authentication file stored in the storage device 22 (Step C12).

Based on this authentication result (step C12)
1) If the user is not a registered user (N of C121)
o), the main program enters a termination procedure (step C1)
6). When it is confirmed that the user is a registered user (Yes in C121), the main program sends the user ID and password input at this time to the security device 12a (Step C13).

On the security device 12a side, the sub-program reads the user ID and the password (step D11). The subprogram stores the information and a database 4 provided in the flash memory 36.
Then, the user is authenticated as a valid user by comparing with the contents of step 1 (step D12).

As a result of the user authentication, the subprogram creates an authentication report describing whether the user is a registrant of the security system, transfers the authentication report to the security device 12a, and controls the PC 11a.
It is passed to the above main program (step D13).

On the PC 11a side, the main program reads the authentication report sent from the security device 12a, and confirms that user authentication has been performed on the security device 12a side (step C14).

Here, when the user authentication denies that the user is a registered user, that is, when the authentication report describes that he is a non-registered user (step C1).
(No in 5), the main program of the PC 11a notifies the user to that effect and suspends the processing (step C16).

When the user authentication confirms that the user is a registered user, that is, when the authentication report indicates that the user is a registered user (Yes in step C15), the main program of the PC 11a executes The following encrypted communication will be executed.

That is, the main program is stored in the storage device 22.
, Read the original text data (creation document) to be encrypted, attach the authentication report thereto and transfer it to the input buffer 34 of the security device 12a, and pass control to the subprogram on the security device 12a ( Step C17).

The reason why the authentication report is attached to the original document is to make the security device 12a confirm that the document is from a registrant authenticated by the security device 12a.

On the security device 12a side, the subprogram reads the original text data sent from the PC 11a (step D14). At this time, if the authentication report is not attached to the original data (N in step D15)
o), it is determined that the document is not a document from the registrant, and the subsequent processing is interrupted (step D16).

On the other hand, if the authentication report is attached to the original text data (Yes in step D15), it is determined that the document is a document from the registrant, and the subprogram is encrypted by an encryption method using a multidimensional vector described later. The original data is encrypted (step D17). Then, the subprogram sends the ciphertext data (encrypted document) together with the decryption key (public key) to the output buffer 3 of the security device 12a.
5 and transmits them to the PC 11a (step D18).

The main program on the PC 11a receives the decryption key and the encrypted data (encrypted document) from the security device 12a (step C1).
8) Either output this as a file on the storage device 22 of the PC 11a, or transfer the control to communication software such as e-mail to transmit it to the outside (PC 11b in FIG. 1) (step C19).

Next, an encryption processing operation performed by the security device 12a will be described. FIG. 6 (a)
Is a flowchart showing an encryption processing operation.

The original text data (message data) to be encrypted is set to M (step E11). This data M is binary data. Security device 1
The subprogram on 2a first scrambles the data M in units of bits (step E1).
2). The data thus obtained is defined as M '(step E13).

Here, the subprogram uses the data M '
Then, XOR (exclusive OR) is performed on the random numbers generated mathematically in sequence and encryption is performed (step E14). At this time,
It is a feature of the present invention that a multidimensional vector r is used as a function for generating random numbers. In this case, a function for generating the multidimensional vector r or a constant used for the function is determined by an encryption key (a secret / public key).

That is, the subprogram reads the secret keys (P ₁ , P ₂ ) and the public keys (P ₃ , P ₄ ) from the database 41 upon encryption, and follows the function using the encrypted keys as constants. Multidimensional vector r
Is generated, and a logical operation such as M′XOR r is performed to encrypt the data M. The ciphertext data thus obtained is set as C (step E15).

More specifically, as shown in FIG. 7, for example, it is assumed that r is a three-dimensional vector (x, y, z), and the vector components x, y, z have a calculation accuracy of 16 bits. The three-dimensional vector r (x, y, z) is sequentially generated as r ₀ , r ₁ , r ₂ , r _3, ... According to equation (1) described later.

[0057] Now, as a sequence of data M 8bit _{data, m 0 m 1 m 2 m} 3 m 4 m 5 m 6 ... when given as (1 character 8bit string), M is the calculation accuracy (16
bit), the element is decomposed into two (8 bits) each. If the three-dimensional vector is r ₀ , the XO of data M and r ₀ (x ₀ , y ₀ , z ₀ )
The R (exclusive _{OR), (xXOR m 0 m 1} ) (yXO
Rm ₂ m ₃ ) (zXORm ₄ m ₅ )... As a result of this calculation, C ₀ C ₁ C ₂ C ₃ C ₄ C ₅ .
Is obtained.

The subprogram further scrambles the data C obtained in this manner in units of bits.
(Step E16). The data obtained in this way is designated as C 'and is output as final ciphertext data (step E17).

In the above-described processing, the level of difficulty in decryption can be increased by repeating C-like encryption with M 'regarded as C'. Further, if the form of the function for generating the multidimensional vector r is changed, the difficulty of decoding will be further increased.

Next, the decryption processing operation executed by the security device 12a will be described. FIG. 6 (b)
Is a flowchart showing a decoding processing operation.

For decryption, basically, the reverse process of the above-described encryption process may be performed. That is, assuming that the ciphertext data is C '(step F11), the security device 12
First, the subprogram on a
The scramble 2 opposite to the scramble 2 performed at the time of the encryption is applied in units of it (step F12). Thus, data C before scrambling 2 is obtained (step F13).

Next, the subprogram decrypts the data C by performing a calculation such as CXORr (step F1).
4). As a result, data M 'before encryption is obtained (step F15).

Then, the sub-program uses the data M '
, A scramble 1 reverse to the scramble 1 performed at the time of the encryption is applied in units of bits (step F1).
2). As a result, data before scrambling 1, that is, original text data M is obtained (step F17).

In the encryption process, C ′ is changed to M ′ again.
If processing for repeating encryption or changing the form of the function for generating the multidimensional vector r is added, the decryption processing is performed in accordance with the processing.

In the present invention, the multidimensional vector r
, A set P of parameters (constants) that determines a function that handles a multidimensional vector r is divided into two parts and expressed as P = {P _s , P _p }. Here, P _s is a secret parameter and corresponds to an encryption key (secret key P ₁ , P ₂ ) stored in a secret part of the database 41. P _p is a public parameter, and corresponds to an encryption key (public keys P ₃ and P ₄ ) stored in the public part of the database 41. P _p is P _s
It is used for user authentication and data encryption and decryption.

In this embodiment, two P _s and two P _p
It is obvious that the number of parameters is not limited to this. Next, the encryption method of the present invention will be described in more detail.

A vector extending in an n (n ≧ 1) -dimensional space is represented by r, and a new vector r is sequentially obtained from its initial value r _0.
Let R be a function that generates _i (i = 0, 1, 2, 3...). At this time, r _i is represented by the following equation (1).

R _i = A · R (P, r _i−1 ) r _i−1 + c (1) where A is an appropriate constant coefficient. P is a set of constants used in the function, and includes an encryption key (private key P ₁ , P ₂ ) stored in a private part of the database 41 and an encryption key (private key P ₁ , P ₂ ) stored in the public part of the database 41. Public keys P ₃ , P ₄ ) are used. c is a constant vector that translates the vector.

In the above equation (1), the coefficient A is a condition for each vector to exist in a closed space region of the multidimensional space when an appropriate constraint (for example, | R | ≦ 1) is provided for the function R. give. When the constant vector c vector r _i converges, (also permitted course c = 0) guaranteed that not a "trivial" point (e.g., meaningless terms such as r = 0).

In the n-dimensional space, the vector r has n elements. r = (x ₁ , x ₂ ... x _n ). On a computer, numerical data is generally the bit length (m) defined by the compiler
(For example, 8 bytes or 64 bits). Therefore, if the vector r cannot be reproduced with an accuracy of n × m data at a certain moment in the vector sequential generation method,
The following vector r cannot be reproduced exactly (or defines a function R such that). This also applies to the initial value r ₀ of the vector r, n × the initial value r ₀
Only when the data is reproduced with the precision of m data, the reproducibility of the following vectors r ₁ , r ₂ , r ₃ ... is guaranteed.

In the encryption according to the present invention, one or more components of the vector r obtained by using the above equation (1) are arranged according to the data definition length, and a character string corresponding to the total bit length is arranged. (8 bits per character is normal) and exclusive logical operation (XOR) for each bit. This is referred to as first encryption.
This is as described in FIG.

This procedure is a measure against decryption. In this case, a new vector may be generated by changing equation (1) and the function R again, and encryption may be performed by the same method as the first encryption. This is referred to as second encryption.

As a specific example, consider the case where n = 2. First, if R is defined as an operation in which only θ rotates around the normal that sets ri _-1 on this plane, R is 2 × 2
And is expressed as follows.

[0074]

(Equation 1)

In this case, θ is a kind of parameter. That is, when the parameter is given as a function of r _i−1 and θ (r) = f (P, r) (3), the conversion represented by the above equation (2) becomes
Formally represented by the above equation (1).

In the above equation (3), P is a function f
Are defined as a set of constants used in the database 41. An encryption key (private key P ₁ , P ₂ ) stored in a secret part of the database 41 and an encryption key stored in a public part of the database 41 (Public keys P ₃ and P ₄ ) are used.

As described above, by using a vector r that spans a multidimensional space generated sequentially for encryption, encryption independent of the processing accuracy and processing ability of a computer can be performed as compared with encryption such as RSA. realizable.

Further, an application can be easily added or changed. Furthermore, in order to decipher the encryption, it is necessary to accurately provide the constant coefficient A, the constant P (secret / public key), the constant vector c, and the initial value r _{0 of the} vector in the above equation (1). Near impossible.

For example, if a three-dimensional vector is considered and P includes five constants, the number of numerical values to be given as the initial value r ₀ is 1 (A) +5 (P) +3 (r ₀ ) +3 ( c) = 12, each of which is an 8-digit real number, 10
All vectors are reproduced with a probability of ^-96 . This probability is almost zero, meaning that decryption is nearly impossible.

Further, in the method used in the present invention,
It is necessary to explicitly give a function f that gives θ of the rotation R (θ), which means that the decryption of the encryption is more complicated.

In the above embodiment, the vector is generated using the function determined by defining the secret key and the public key. However, the vector is generated using at least the function determined by defining the public key. May be.

The constants (A, P, C) for determining the vector generation function are fixed at the start of use and the function type is fixed. (Encryption key used as a part of public key) can be applied.
An application example is shown below.

(Second Embodiment) Vectors defined in a closed area of an n-dimensional (n ≧ 1) space are sequentially generated,
In encryption using a function in which the generated vectors do not match each other, each constant that determines the function has a password dependency. The password is used as a part of the public key. The function type is fixed. That is, in the above equation (1), A → A (K) P → P (K) c → c (K). Here, A is a constant coefficient, P is a set of constants (private / public keys) used in the function, c is a constant vector that translates the vector, and K is a password.

The password K is input by the user,
It is stored in the public part of the database 41. The sub-program reads the password K from the database 41, and determines each constant (A, P, C) of the above equation (1) based on the password K. Then, a multidimensional vector is generated by a function using these constants, and data is encrypted.

As described above, by giving each of the constants determining the function the dependency of the password, the security of the encryption can be further improved as compared with the case where each of the constants is fixed.

(Third Embodiment) A vector defined in a closed region of an n-dimensional (n ≧ 1) space is sequentially generated,
In encryption using a function in which the generated vectors do not match, each constant that determines the function has a dependency on a password and real time. The password is used as a part of the public key.
The function type is fixed. That is, in the above equation (1), A → A (K, t) P → P (K, t) c → c (K, t). Here, A is a constant coefficient, P is a set of constants (private / public keys) used for the function, c is a constant vector that translates the vector, K is a password, and t is real time.

The password K is input by the user,
It is stored in the public part of the database 41. The sub-program reads out the password K from the database 41 and determines each constant (A, P, C) of the above equation (1) based on the password K and the real time t. Then, a multidimensional vector is generated by a function using these constants, and data is encrypted.

As described above, by giving each of the constants for determining the function the dependency of the password, and by giving each of the constants the dependency of the real time, each of the constants is determined not only by the password but also by the real time. Therefore, the security of the encryption can be further improved.

(Fourth Embodiment) Vectors defined in a closed region of an n-dimensional (n ≧ 1) space are sequentially generated,
In encryption using a function in which the generated vectors do not match, each constant that determines the function has a dependency on a password and real time. The password is used as a part of the public key.
In addition, the function type selection has a password dependency. That is, in the above equation (1), A → A (K, t) P → P (K, t) c → c (K, t), and R → R _k . Here, A is a constant coefficient, P is a set of constants used for the function (secret / public key), c is a constant vector that translates the vector, K is a password, t is real time, and R is a function. is there.

The password K is input by the user,
It is stored in the public part of the database 41. The sub-program reads out the password K from the database 41 and determines each constant (A, P, C) of the above equation (1) based on the password K and the real time t.

The subprogram selects a function R using these constants according to the password K. And
By using the selected function R, a multidimensional vector is generated and data is encrypted.

As described above, each constant for determining a function has a password dependency, each constant has a real-time dependency, and a function is selected according to a password. The constants change not only with the password but also with the real time, and since the function itself using the constants is selected by the password, the accuracy of the encryption can be further improved.

(Fifth Embodiment) Vectors defined in a closed region of an n-dimensional (n ≧ 1) space are sequentially generated,
In encryption using a function in which the generated vectors do not match, each constant that determines the function has a dependency on a password and real time. The password is used as a part of the public key.
In addition, the selection of the function type is made dependent on the password and the real time. That is, in the above equation (1), A → A (K, t) P → P (K, t) c → c (K, t) and R → R _{k, t} . Here, A is a constant coefficient, P is a set of constants used for the function (secret / public key), c is a constant vector that translates the vector, K is a password, t is real time, and R is a function. is there.

The password K is input by the user,
It is stored in the public part of the database 41. The sub-program reads out the password K from the database 41 and determines each constant (A, P, C) of the above equation (1) based on the password K and the real time t.

The subprogram selects a function R using these constants according to the password K and the real time t. Then, a multidimensional vector is generated by the selected function R, and data is encrypted.

As described above, each constant for determining a function has a password dependency, each constant has a real-time dependency, and a function is selected according to the password and the real time. Therefore, each constant changes not only with the password but also with the real time, and the function itself using those constants is selected according to the password and the real time, thereby further improving the security of encryption. Can be.

(Sixth Embodiment) Vectors defined in a closed region of an n (n ≧ 1) -dimensional space are sequentially generated,
A new function is defined by linearly combining a plurality of functions whose respective generated vectors do not coincide with each other. For each of the combined functions, a password and a real-time Make it dependent. The password is used as a part of the public key. In addition, the selection of the function type is made dependent on the password and the real time. Further, the linear combination coefficient is made dependent on the password and the real time.

That is, a vector extending in an n (n ≧ 1) -dimensional space is defined as r, and a function for sequentially generating new vectors r _i (i = 0, 1, 2, 3,...) From its initial value r _0. Where R _j (j = 0, 1, 2, 3,...), R _i = Σ _j W _j (K, t) ｛A _j (K, t) R _{j, k, t} (P _j (K , T), r _i-1 ) + c _j } (4) to generate a new vector.

Here, A is a constant coefficient, P is a set of constants (secret / public keys) used for the function, c is a constant vector that translates the vector, K is a password, t
Is real time and R is a function. W is a linear combination coefficient.

The password K is input by the user,
It is stored in the public part of the database 41. The sub-program reads the password K from the database 41 and determines each constant (A, P, C) of the above equation (4) based on the password K and the real time t. Subprogram, password K function R _j with a plurality of functions linearly formation
And according to the actual time t.

The linear combination coefficient W _j used for the function R _j is determined by the password K and the real time t. Then, this selected function R _j, and generating a multidimensional vector, encrypts the data.

As described above, a new function obtained by linearly combining a plurality of functions is used. For each function, a constant for determining the function has a password and a real-time dependency. By providing real-time dependency, and by giving the linear combination coefficient a password and real-time dependency, the security of encryption can be further improved.

(Seventh Embodiment) Vectors defined in a closed region of an n-dimensional (n ≧ 1) space are sequentially generated,
In encryption using a function that does not match each generated vector, the function type is arbitrarily defined by the user,
Dynamically combine with the main body encryption algorithm when used so that it can be used.

In other words, a function obtained by compiling a user-defined function for sequentially generating multidimensional vectors into an already-encrypted “basic program” is dynamically linked and used at the time of executing all programs. I do. In this way, it is expected that a malicious user, such as a hacker, will make decoding almost impossible.

[0105]

As described above, according to the present invention, n (n ≧ n)
1) Vectors defined in a closed area of a dimensional space are sequentially generated, and ciphertext data is generated by a logical operation between original text data to be encrypted and components of the vectors. Encryption can be performed without requiring a high-precision operation capability such as the RSA method, and furthermore, encryption with high reliability and easy addition and change of applications can be realized.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing the configuration of a system for performing cryptographic communication according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a PC and a security device used in the system.

FIG. 3 is a view showing a configuration of a database on the security device.

FIG. 4 is an exemplary flowchart showing processing operations of the PC and the security device at the time of user registration in the embodiment.

FIG. 5 is an exemplary flowchart showing processing operations of the PC and the security device at the time of data encryption in the embodiment.

FIG. 6 is an exemplary flowchart showing processing operations of encryption and decryption in the embodiment.

FIG. 7 is a diagram for explaining a calculation method of encryption using a multidimensional vector according to the present invention.

[Explanation of symbols]

 11a, 11b PC 12a, 12b Security device 21 CPU 22 Storage device 23 RAM 24 Keyboard 25 Display unit 26 Card I / F 27 Connector 31 CPU 32 ROM 33 RAM 34 Input buffer 35 output buffer 36 flash memory 37 connector 41 database

Claims (8)

[Claims] 1. An original text data acquisition unit for acquiring original text data to be encrypted, and a vector generation unit for sequentially generating a vector defined in a closed region of an n (n ≧ 1) -dimensional space. A logical operation unit for performing a logical operation of the original text data obtained by the original text acquisition unit and a component of the vector generated by the vector generation unit in bit units to generate ciphertext data. Encryption device. 2. The method according to claim 1, wherein the vector generating means sequentially generates the vectors using a function determined by defining at least a secret key, wherein each of the generated vectors does not match. The encryption device according to claim 1, wherein 3. The method according to claim 2, wherein the vector generation means sequentially generates the vectors using a function determined by defining a secret key and a public key, and the generated vectors do not match. The encryption device according to claim 1, wherein: 4. The encryption apparatus according to claim 1, wherein said vector generation means sequentially generates vectors using a function determined by a constant depending on real time. 5. The encryption apparatus according to claim 1, wherein said vector generation means makes the selection of a function for generating a vector depend on a public key. 6. The encryption apparatus according to claim 1, wherein said vector generation means makes the selection of a function for generating a vector have a dependency on a public key and real time. 7. The method according to claim 1, wherein said vector generation means defines a new function by combining a plurality of functions, and sequentially generates a vector using the defined function. Encryption device. 8. A logical operation of sequentially generating vectors defined in a closed region of an n (n ≧ 1) -dimensional space, and performing an operation on original text data to be encrypted and components of the generated vectors In bit units to generate ciphertext data.