JPS6255789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information conversion/restoration device, and more particularly to an information conversion/restoration device capable of performing multi-step information conversion and restoration.

In recent years, there has been rapid progress in so-called office automation to improve the efficiency of administrative departments, but ultimately office automation is said to be about automating the ``information processing'' that is the main task of the office. . For this reason, it is necessary to digitize the ``paper'' that currently stores information in offices so that it can be processed automatically. In this electronic office file system, unlike the traditional storage and distribution of paper documents, all information is electronically stored in one place, and recipients can simply The system is such that only the distribution notification is sent, and the document can be obtained by requesting distribution of the electronic file when the person wishes.

The flow of information in this computerized office file system is, for example, when Mr. A of the 1st section of the 1st department creates a document, receives approval from the section manager B and the manager C, and then sends it to the 2nd department's section manager D and Mr. E. If you want to distribute it to the section manager, it will look like this:

(b) Creating a document Mr. A searches for the example sentence of the target document from the example collection in the central file, copies it, and then creates a new document by modifying and adding to it using the word processor function of the workstation. do.

(b) Inspection/approval Mr. A sends the created document to an electronic file with instructions for distribution to Section Manager B. Manager B receives the notification of this distribution designation, reads the document created by Mr. A from the electronic file, inspects the contents, and then sends it to Mr. C.
Add the distribution instruction to the manager and send it to the electronic file again. At the same time, the first document sent by Mr. A will be deleted. Upon receiving notification of the distribution designation, Manager C reads out the document reviewed by Manager B, gives approval, and then sends it to an electronic file with a distribution designation to Manager D and Manager E. At this time, the document from Section Manager B will be deleted.

(c) Distribution After receiving the notification of distribution designation, Section Managers D and E each receive the document by reading it from the electronic file at their convenience. Documents on electronic files are sent to Section Manager D and E.
It will be deleted upon notification of unnecessaryness from the section manager or after a certain period of time has passed.

In the above-mentioned office file system, all documents are converted into electrical signals and stored, so (1) a person without operational authority may illegally send or rewrite the information in the file; (2) A third party may intercept communications when a person with legitimate operating authority is communicating with an electronic file; (3) Distributing or registering a document under the guise of another person. , (4) Even though the document was created by oneself, there are cases in which it is not possible to completely preserve the document information due to acts of sabotage or confusion, such as denying that the person created the document.

In order to prevent the threat of such interference and confusion and maintain the confidentiality and security of documents, it is necessary to convert the created documents using a specific conversion key (so-called encryption) and to own the conversion key. Although it is effective to ensure that the conversion key can only be read by the person concerned, it is practically impossible for management reasons to distribute the conversion key generated at that time to all concerned parties each time a document is created. In order to solve this problem, we use two arbitrary prime numbers, and use one of the two numbers derived through a certain mathematical procedure as a public conversion key and the other as a secret conversion key (hereinafter referred to as This is called the RSA method of communication.
ACM Fed.1978 p.120-126) has been proposed. In this method, a document converted using a public conversion key can only be recovered using a private conversion key, and conversely, a document converted using a private conversion key can only be recovered using a public conversion key. It has the feature that there is no need to distribute conversion keys because it is

Using the features of this RSA method, documents created for distribution (hereinafter referred to as main information) are converted using a conversion key (hereinafter referred to as verification information) using an ordinary high-speed calculation method, and verification information is of
A method has been proposed in which conversion is performed using a conversion key based on the RSA method, and two pieces of information, namely converted main information obtained by converting this main information and converted verification information obtained by converting verification information, are sent and received. (What is the RSA method?
Select two arbitrary prime numbers p and q, and calculate the product (p-1)・
(q-1), and the product (p-1)・(q-
1) When the smaller number is e, (p-1)・
An operation where (q-1) is the “modulo”, that is, modulo
In (p-1) and (q-1), the reciprocal of e is d, that is, e and d = lmod, and the conversion key is the number d and e that satisfy (p-1) and (q-1). , the greatest feature of this method is that it can restore what was converted to e to d (or what was converted by d to e). Normally, d is unique to each individual, given to them upon joining the company, etc., and is not made public. Only that specific individual keeps it secretly and owns and uses it in the form of a magnetic card or the like. On the other hand, e, together with the prime number product n (n=p.q), is disclosed to all concerned parties in a format such as a telephone directory, and anyone can use it. Generating d from e is a prime number p
and q is unknown, let n be the prime factors p and q
It is practically impossible because it is practically impossible to decompose into Hereinafter, e will be referred to as a public key, and d will be referred to as a private key. ) In the document conversion/restoration method using the above method, the long main information is a conventional conversion key (verification information) such as the DES method, which is a national standard established by the U.S. Department of Commerce.
Convert only verification information to RSA
Conversion key by method (200 to maintain sufficient security against decoding of the conversion key in RSA method)
It is said that it is necessary to take values on the order of digits, and the processing time required for conversion and restoration is considerably longer than that of conventional conversion keys), so the overall processing time is Not only does this have the effect of increasing the security of confidentiality with little change, but the creators, reviewers, approvers, etc. of the main information can multiple times use their own private keys for verification information. Therefore, by performing the conversion, an operation equivalent to a signature to clarify each person's responsibility can be obtained. This can be useful in preventing disturbances and disorderly behavior.

However, when performing multiple conversion operations using the above-mentioned RSA method, there are disadvantages in terms of processing speed and system simplicity. An example of this will be explained with reference to FIG.

Document creator A performs conversion (signature) on verification information K for converting main information using secret key _dA . This is expressed as S _A =K ^dA mod.n _A (n _A =p _A ·q _A ) (reference number 51). As a result, the signature text S _A takes a value up to n _A -1.

In response, the next signer (reviewer) B will sign on it (converted using B's private key d _B ), but at this time B's prime number product n _B (=p _B・q _B )
When is smaller than n _A , it is impossible to process mod.n _B unless S _A is divided into blocks smaller than n _B-1, so we divide S _A into two blocks, S _A1 and S _A2 ( 52), on which a transformation is performed using the private key d _B (reference number 53). Furthermore, the prime number products n _C and n D of approver C and distributor _D
When n _B > n _C > n _D , reference numbers 53 to 57 in Figure 1
As shown in the figure, the number of times of processing gradually increases. Therefore, such a case has the disadvantage that the processing time becomes long and the processing equipment becomes complicated due to the change in the number of blocks and the block length. (Normally, the position in the office is higher in the order of A → B → C, but this is not necessarily the order of employment, and therefore the relationship n _A < n _B < n _C is not always guaranteed. ) The object of the invention is therefore to eliminate the above-mentioned drawbacks and to
Since n _A < n _B < n _C < n _D is guaranteed, it is possible to perform processing in which the block length does not increase even in the case of multi-step conversion. Therefore, the processing speed is fast and verification information conversion/
An object of the present invention is to provide an information conversion/restoration device whose restoration section has a simple configuration.

The information conversion/restoration device of the present invention includes a verification information generating section that operates according to a command from a control device and outputs verification information for converting main information, and a verification information generation section that operates according to a command from the control device and outputs verification information for converting main information. The following conditions (1)
and verification information conversion first key e that satisfies condition (2)
Or, when the verification information conversion second key d and the verification information are input, the conversion verification information is output, and the verification information conversion first key e or the verification information conversion second key d and the conversion verification information are input. Verification information conversion that outputs the restored verification information when
a restoring unit, and operates in response to instructions from the control device;
When the verification information and the main information from the host device are input, the main information converted from the main information is output, and when the verification information and the main conversion information are input, the main information converted is restored. A main information conversion/restoration unit that outputs the main information or operates in response to instructions from the control device, inputs the verification information and main information from the host device, and outputs converted main information obtained by converting the main information. a main information converting unit; and a conversion main information restoring unit that operates in response to a command from the control device, inputs the verification information and the conversion main information, and outputs the main information obtained by restoring the converted main information. configured.

However, as condition (1), the verification information conversion first key e is coprime to the product (p-1) and (q-1) when two arbitrarily selected prime numbers are p and q. and is an arbitrary prime number smaller than the product (p-1)/(q-1), and as condition (2), the verification information conversion second key d is:
An operation in which the product (p-1), (q-1), and (r-1) of the prime numbers p, q, and the third prime number γ is the "modulo", that is, modulo (p-1), (q-1).・(r
-1), the reciprocal of e, that is, e・d=lmod.(p−1)・(q−1)・(r−1), and the third prime number r is the arbitrary 2 Any finite set of products of prime numbers
When No, for any two elements n _x and n _y of No, n _x · r _i-1 < n _y · r _i , i = 1, 2, 3, 4, ... and r ₀ = 1 Any one of r ₁ , r ₂ , r ₃ , ... that always satisfies
Individual.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Referring to FIG. 2a, which shows a block diagram of an example in which an embodiment of the present invention is applied to the conversion operation of main information,
The verification information generating device 2 receives a command signal 22 from a control device 8 which operates in response to a command signal 20 from the outside, and sends a random value to the main information conversion/restoration section 6 and the verification information conversion/restoration section 4 each time. The verification information K to be taken is output. The main information conversion/restoration unit 6 inputs the main information M from the outside, and the verification information generation unit 2
When the verification information K is inputted from the controller 8 and the command signal 24 is received from the control device 8, the converted main information Mx obtained by converting the main information M using the verification information K is output. In addition, the verification information conversion/restoration unit 4 inputs verification information K from the verification information generation unit 2, and receives a public key e or a private key (described later) from an external input device 10 (for example, a magnetic card reader, a keyboard input device, a card reader, etc.). When d is input and a command signal 26 is received from the control device 8, conversion verification information Sx (X=A, B,
C...) or output C.

Further, referring to FIG. 2b, which shows a block diagram of an example in which the embodiment of FIG.
Sx or C is input, and the private key d or public key e is input from the input device 10, and upon receiving the command signal 27 from the control device 8, the conversion verification information Sx
Alternatively, the verification information K obtained by restoring C is output. The main information conversion/restoration unit 6 also receives converted main information Mx that is directly transmitted from another information conversion/restoration unit or is temporarily stored in a file device such as an optical disk device and sent out as its output. Verification information K is input from the verification information conversion/restoration unit 4, and the main information is converted by receiving the command signal 25 from the control device 8.
The main information M obtained by restoring Mx using the verification information K is output. Note that at this time, the verification information generating section 2 does not perform any special function.

Next, the operation of the information conversion and restoration apparatus constructed as described above will be explained with reference to FIG.
(Verification information conversion operation 40, 4 in FIG.
2, 45 and 46 and conversion verification information restoration operations 41, 43 and 44 are performed in the verification information conversion/restoration section 4 in FIG. This is performed in the main information conversion/restoration unit 6 in FIG. ) First, when a document creator signs a document he created using this device and sends it to reviewer B, he inputs his own private key _dA from the magnetic card reader 10A and enters the document (main information) M. Conversion verification information S A obtained by converting verification information K, which is a conversion key, by the calculation of equation (1) _below , and conversion main information, which is obtained by converting main information M by a conventional conversion method (for example, DES method) using verification information K. Send to reviewer B along with information Mx.

S _A = K ^dA mod.n _A ......(1) When reviewer B receives this conversion main information Mx and conversion verification information S _A , he inputs document creator A's public key e _A from the keyboard 10B. Conversion verification information S _A
is restored by the calculation in (2) below, the converted main information Mx is restored using the restored verification information K, and this is displayed on the display device 20 to point-inspect the contents.

S _A ^eA mod.n _A = K ^dA

Claims (1)

[Scope of Claims] 1. A verification information generation unit that operates in response to a command from a control device and outputs verification information for converting main information; Verification information conversion first key e or verification information conversion second key d that satisfies (1) and condition (2)
and the verification information are input, the conversion verification information is output, and when the verification information conversion first key e or the verification information conversion second key d and the conversion verification information are input, the restored verification information is output. a verification information conversion/restoration unit that outputs a verification information conversion/restoration unit that operates in response to a command from the control device, and outputs converted main information obtained by converting the main information when the verification information and main information from the host device are input. , when the verification information and the conversion main information are input, the main information conversion/restoring unit outputs the main information obtained by restoring the conversion main information, or operates in response to a command from the control device, and outputs the main information obtained by restoring the conversion main information, and operates in response to a command from the control device, and outputs the main information obtained by restoring the conversion main information. a main information conversion unit that inputs main information from the device and outputs converted main information obtained by converting the main information; and a main information conversion unit that operates in response to instructions from the control device and inputs the verification information and the converted main information. An information conversion/restoration device comprising: a conversion main information restoration unit that outputs the main information obtained by restoring the conversion main information. However, as condition (1), the verification information conversion first key e is the product (p-1)・(q-
1) and the product (p-1)・(q-1)
Any smaller prime number, and as condition (2), the verification information conversion second key d is the product (p−1)·(q−
1) Operation with ・(γ-1) as “modulo”, i.e.
modulo (p-1), (q-1), (γ-1), satisfies the reciprocal of e, that is, e・d=1mod・(p-1)・(q-1)・(γ-1) As a numerical value, the third prime number γ is nx・γ _i-1 <ny for any two elements nx, ny of No, where No is an arbitrary finite set of the two arbitrary prime numbers. - Let γi, i=1, 2, 3, 4, ... be any one of γ ₁ , r ₂ , γ ₃ , ... that always satisfies γ ₀ =1.