JPS60247683A - Data protection managing system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to distributed management of information and a system for encrypting and protecting data.

[Prior art]

Conventionally, this type of encryption system includes the US data encryption standard CDBS) and the public key encryption system (for example, Norihisa Doi, 1 US Data Encryption Standard DKS'', Computer Science, blt Vol.

13, 隨2. (See P4-P15 Kyoritsu Shuppan (1981))
.

The US Data Encryption Standard (DBS) divides the original information string into blocks of 64 bits each, uses each block as an input block, performs substitution and transposition processing), and generates an encrypted 64-bit output. It creates information. In other words, if a 64-bit key is used for an input block, a ciphertext of K is generated. In DBS, the encryption key and decryption key are the same, but in public key cryptography, the encryption and decryption keys are different, so the encryption key is made public.

Conventional encryption methods of this type were configured as described above, so that as long as one piece of encrypted information and the key to decrypt it are needed, the original information string can be easily reproduced. There were some drawbacks.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it divides the original information string into a plurality of pieces of encrypted information, and extracts a certain number or more pieces of divided information from among them. The aim is to provide a data protection management system that enables distributed management of information and keys so that the original information sequence can be reproduced by collecting the information.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is a database used as the original information string f←), 2 is divided information that is divided into N pieces and is managed in a distributed manner, and 3 is a database 4 that is reproduced (more than one piece of N pieces of divided information 2). 5 is an encoder that divides the original information string f←) into N pieces, and 5 is a decoder that reproduces the original information string f) from N pieces of divided information 2 or more. Encoder 4 lines Multiple Galois fields G (F2) input in parallel as shown in Figure 2
The decoder 5 includes a %GF(2) multiplier 7 and a CF(2) divider 8 as shown in FIG.
and GF(2) multiplier 9 in parallel, 9. GF(
2) 0F (2) adder 10 that adds each output of the multiplier 3
and outputs the original information string f←).

In general, the problem of whether the original data can be reproduced by dividing the original information sequence f←) into N parts and collecting any number of them is called the (K,N)L threshold problem. . In this invention, this problem is solved by applying the Chinese remainder theorem for the following integers extended to polynomial clothes.

(1) Explain the Chinese remainder theorem for integers.

Let cho (1=1, 2, . . . or) be a relatively prime integer, and let M=cho 1=1. At this time, any integer aI (1=1s2m...
or) is given, then there is always only one integer f that satisfies f=ml m(mod IIJ)0≦f(M).

For example, ml = 5, m2 = 6 + m5
= 7, then M=21G.

If m1=2, m2=4, m5=1, then f;
It becomes 22.

i.e. - holds true.

佽) Explain the Chinese remainder theorem for polynomials.

Let (i=1, 2, . . . , N) be a polynomial in a disjoint Galois field 2 (GF(21)f).

far.

When an arbitrary polynomial Omachi (b) (1-1, 2, . . .

By the Chinese remainder theorem extended to the above polynomial, we can derive the following relation:

t(d in ml(x)(1=1, 2*・mN7't'
Let the remainder of 9 be al (b). At this time, fω is arbitrarily selected from N 1□) (1=1
．． 2. ...SX) can be played as follows.

When these relational expressions correspond to the system shown in Figure 1, town (b) is a polynomial characterizing N division, K is the number of reproductions, and a
ict) corresponds to the N pieces of divided information 2, and f(b) corresponds to the original information string.

Now, if m1k)(igl, 2, . . ., N) are all polynomials of degree d, then fω is a polynomial of degree dK−1, that is, the original information sequence f←)
is the information amount of dK bits. Also, al (b) is Ifl
Since it is the remainder after dividing by i←), the d-1 degree polynomial, that is, the division information 2 has an information amount of d bits. Therefore, it can be seen that the information amount of each divided information 2 is 1/ of that of the original information sequence f←).

For example, N=3. = 2, disjoint fourth order (d =
4) Select three polynomials on GF(21).

ml(→=x-)-x-)-1・・・・・・・・・・・・
・ (9) mz (→= x1'+ x2+ 1...
・・・・・・・・・ α1m5(→= x'+x'
+ 1 ・・・・・・・・・・・・ aυ The original information string of the database 1 is divided into blocks of dK bits, that is, 8 bits each, and the encoder 4 performs division encoding. Assuming that one block of information string is 10100011, it is expressed as f 侃) =x +x -1-x+1. Furthermore, the division information 2 at this time consists of three GFs (
21 The remainder of the divider 6 is ax(x)zf(x)/m1(dxx3-1-x'+x
→1110 ・-Qg)12(X);HfCT-Vm
2CX)E;-x'+x+1 4 1011 - 33
)ms6c)=fCxVms(d==xu+x”+x+
1- 1 1 1 1 -...Q4). In this way, 4 bits (original information string f(ro))
N pieces of division information 2 (OA=amount of information), that is, three pieces are created. Before decoding this, J←) in equation (8) is calculated.

(1) When using Qlden) and 12(b) during playback tl(
→=x2−)−x+1 ・・・・・・・・・φ)12
(Resistance = 22 + 1 .....
・・・・・・・・・ (a) t5←)=x ・・・・
・・・・・・ (G) to 7i) When playing, smell (B) and 11←
) when using tS(→= x'+z+1 ・・・・・・
... (g) tIden) = x5 + x2 ...
(1) Finally, a case will be described in which the arbitrary pieces of divided information 2 and the original information sequence fk) are decoded by the decoder 5.

1i) When decoding ms (b) and aS, formula (7) K
Formula (9), Ql, Cl2), Q3), 015)
, 06) and decode (ii) to a) and aB transmission): Equation (7)
3) , α4) , (1'f) , Cl8) and decoded as above, the formula (21X22X2
3) correctly reproduces the original information string f (x) in any case and creates database 3 with the same content as original database 1.
can be played.

The decoding operation of equation (21) will be explained with reference to FIG.

Ql transmission, which is two pieces of divided information 2 input to the decoder 5)
and a 2(X) is G F (t
l(g), t26C)Iii), and output as 11 (→al(b) and t2(X)a2), respectively. Next, nod ml (b) mz of equation (21) (in order to maintain the illusory relationship, K G F' (2+input to the divider 8 and become mL).

mz(x), mJx), the respective remainders are output, and are further divided by the GFT21 multiplier 9 to mz(b), ttk)a, 1(b) and ml, respectively.
(→tg((trans)heat 2←) is the output.The last K G
F (21 As a result of adding them in the adder 10, the original information string f(b) is obtained. □In this invention, since the divided information 2 has only 14 information amounts of the original information string f←) , it is clear that the original information string f cannot be reproduced correctly from less than K pieces of divided information 2. On the other hand, from the divided information exceeding , according to equation (7), attached information consisting of the reproduced original information string f) and an information sequence of all "'0" is obtained, and this attached information By checking whether the information is all 1''Oj', it is possible to determine whether the original information string has been correctly reproduced.

〔Effect of the invention〕

As described above, according to the present invention, if any number of pieces of N pieces of divided information are collected, the original information string can be reproduced, but if less than 11 pieces of N pieces of information are collected, the original information string cannot be reproduced. If it is +1 or more, it is possible to check whether the original information string was correctly reproduced, so it is possible to check the confidentiality of the divided information, the reproducibility of the divided information against loss or theft, and the tampering of the divided information. , it is possible to construct a new data distributed management system characterized by the ability to detect and correct noise errors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a data protection management system according to an embodiment of the present invention, FIG. 2 is a block diagram of the encoder shown in FIG. 1, and FIG. 3 is a block diagram of the decoder shown in FIG. be. 1... Database, 2... Division information, 3... Database, 4... Encoder, 5... Decoder, 6,
8...GF(2) divider, 7,9...GF(2)
+ multiplier, 10...G F f21 adder. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. U Figure 1

Claims (2)

[Claims] (1) In a system that manages information in a distributed manner, the original information is encoded as multiple pieces of divided information based on the Chinese Remainder Theorem extended to polynomial clothes, and arbitrary information is selected from among the encoded pieces of divided information. A data protection management system characterized by collecting a certain number or more pieces of divided information and uniquely decoding an original information string. (2) Claim 1, characterized in that it is determined whether or not the original information string that has been decoded by collecting a certain number or more pieces of divided information is logically correctly reproduced. data protection management system.