JP4611769B2 - Electronic procurement bidding method, electronic procurement bidding system, and electronic procurement bidding program - Google Patents

Description

  The present invention relates to an electronic procurement bidding method, an electronic procurement bidding system, and an electronic procurement bidding program for determining a successful bidder based on price and quality.

  The procurement bid handled in the present patent application is, for example, a bid of one buyer, a plurality of sellers, and a bid for quality as well as price, and the seller who presents the lowest price does not always make a successful bid. Quality includes product quality, quantity, and delivery time.

2. Description of the Related Art Conventionally, there is a technology that realizes bidding for a state-profit procurement (see Non-Patent Document 1, for example). Hereinafter, the method disclosed in Non-Patent Document 1 will be described.
If the winning bid price is p and the quality is q (may be two or more dimensions), the buyer's utility is V (q) -p, which is an ordinary quasi-linear utility.
However, it is assumed that the function V (q) is a utility when the payment is not considered when the quality is q, and the function V (q) is known.

If the type of seller i who has made a successful bid is θ _i , the utility of the seller is pc (q, θ _i ), which is a normal quasi-linear utility.
The type θ _i is information such as a manufacturing cost that determines the manufacturing cost c (q, θ _i ) of a product of quality q, and is important secret information of the manufacturer (seller). Further, the manufacturing cost c (q, θ _i ) is a manufacturing cost of the product of the quality q of the seller _i and depends on the type θ _{i of the} seller i.

  Non-Patent Document 1 has the following strategies-proof (the honest strategy is the best strategy), individual relational (no loss by participating in bidding), pareto effective (successful bid results are social surplus (participants) The sum of the utility) is maximized).

A bid is made by each seller i declaring his type θ _i to the buyer. It should be noted that because of strategy-prof, it can be assumed that each seller i declares the true type θ _i to the buyer.
The bid opening is performed as follows. The seller i _1st and the quality q _1st that maximize the social surplus V (q) −c (q, θ _i ) are obtained, and the seller i _1st becomes the winning bidder. Further, the seller i _2nd and the quality q _2nd that increase the social surplus V (q) −c (q, θ _i ) second are obtained. Then, the reward of seller i _1st who is the successful bidder is obtained by calculating V (q _1st ) − {V (q _2nd ) −c (q _2nd , θ _i2nd )}. Then, the seller i _1st is disclosed as a successful bidder, and the calculated reward is disclosed as a reward for the seller i _1st .

Conventionally, there is a technology related to information security technology (see, for example, Non-Patent Document 2). Non-Patent Document 2 is an encryption that realizes a Vickley auction that can verify the correctness of the auction calculation result while concealing the bid price. The protocol is disclosed. The system disclosed in Non-Patent Document 2 will be described below.
The public key cipher E used is a secure (IND-CPA) public key cipher that satisfies homomorphism (E (a) E (b) = E (ab)), such as ElGamal cipher. In addition, it is assumed that a number z other than 1 in the range that can be a ciphertext equivalent and a bid price list P = {1, 2,...

Bidding is conducted as follows. Seller i (i = 1~N) decided the bid price ba _i, the bid price element _ca 1 shown below for _{ba i, i, ca 2,} i, ···, ca p, ciphertext consisting of _i The column Ca (ba _i ) = (ca _{1, i} , ca _{2, i} ,..., Cap _{, i} ) is generated. However,
ca _{j, i} = E (z): j = 1, 2,..., ba _i
ca _{j, i} = E (1): j = ba _i +1, ba _i +2,..., p
It is. Then, the ciphertext string Ca (ba _i ) and the asymmetric zero knowledge proof of correct creation are disclosed and a bid is made.

The bid opening is performed as follows. The j-th element ca _{j, i} of the ciphertext string Ca (ba _i ) of each seller i (i = 1 to N) is integrated, and the element product ca _j (= ca _{j, 1} ca _{j, 2} ... ca _{j, N} ). However, due to the homomorphism of the public key encryption E, ca _j = E (z ^{n (j)} ). Note that n (j) = # {1 | j ≦ p _i } is the number of bidders who bid at a price of j or higher. It is determined whether or not D (ca _j ) ε {1, z, z ² } is satisfied by the distributed decryption with proof by the distributed decryption server and the Mix and Match technique described in Non-Patent Document 2, and n ( A bid price ba _{2nd in} which ba _2nd ) is 2 or more and n (ba _2nd +1) is 1 or less is obtained. If ba _2nd +1 is described as x (the same applies hereinafter), the elements ca _{x, 1} , ca _{x, 2} ,..., Ca _{x, N} are decoded and decoded D (ca _{x, 1} ). , D (ca _{x, 2} ),..., D (ca _{x, N} ), thereby determining the seller i _1st corresponding to the element Ca _{x, 1st} whose decoding result is z as the successful bidder. Then, the seller i _1st is disclosed as a successful bidder and the bid price ba _1st is disclosed.
The security of the public key cryptography E ensures the secrecy of the bid price. Moreover, since the non-dialogue zero knowledge proof is attached, the correctness of the calculation result can be verified. In addition, the necessary number of communication is O (n + log (p)), and the necessary number of communication when the secret circuit calculation is used is more efficient than O (n ² × nlog (p)).
Takayuki Suyama and Makoto Yokoo, “Strategy / False-name Proof Protocols for Combined Multi-Attribute Procurement Auctions, 160 A4, InAp. Masayuki Abe and Koutaruou Suzuki, “M + 1-st pricition usage using homology cryptography”, In Public Key Cryptography 2002, pages 115-124.

  Although the said nonpatent literature 1 implement | achieves a procurement bid, there exists a problem that the type which is important confidential information of a manufacturer (seller) must be declared. Moreover, although the said nonpatent literature 2 was able to conceal a bid price in a normal bid, it was not able to implement | achieve until a bid price was concealed in a procurement bid.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic procurement bidding method, an electronic procurement bidding system, and an electronic procurement bidding program that make it possible to conduct procurement bidding while concealing types that are important confidential information of sellers. To do.

The electronic procurement bidding method of the present invention is an electronic procurement bidding method in which bidding based on price and quality is performed. The bidder apparatus on the side of each seller i (i = 1 to N) depends on the type θ _{i of the} seller i and the quality q the a variable function {V (q) -c (q , θ i)} and quality calculation procedure for determining the quality q _i which maximizes the quality q _i of each said bidder device obtained in the quality algorithm tender opening of the price calculation procedure for determining the function value b _i of the function, of each of the bidders device said quality calculating quality obtained in step q _i and the price algorithm buyer a function value b _i determined in Declaration information transmission procedure to be transmitted to the bidder apparatus, declaration information reception procedure for the bidder apparatus to receive the quality q _i and the function value b _i transmitted by each bidder apparatus, and the bidder apparatus to the reporting information Receive in the reception procedure Quality q _i and the reporting information registration procedure the function value b _i is stored in the reporting information storage means in association with the seller i, the bid opening's device function value b _i is the maximum from the statement data storage unit seller i _1st Using the successful bid information extraction procedure, and the bidder device uses the quality q _1st corresponding to the maximum function value b _i stored in the declaration information storage means and the function value b _2nd having the second largest value. The reward calculation procedure for calculating the reward of seller i _1st by calculating {V (q _1st ) −b _2nd }, and the bidder apparatus releases seller i _1st extracted in the successful bid information extraction procedure as a successful bidder. And a successful bid information disclosing procedure for disclosing the reward determined in the reward calculating procedure as the reward of the winning bidder.

The electronic procurement bidding method of the present invention is an electronic procurement bidding method that performs bidding based on price and quality, public key cryptography E satisfying homomorphism, number z other than 1 within a range that can be a ciphertext, and bidding The price list P = {1, 2,..., P} is disclosed, and the bidder apparatus on each seller i (i = 1 to N) side depends on the type θ _{i of the} seller i and uses the quality q as a variable. The quality calculation procedure for obtaining the quality q _i that maximizes the function {V (q) −c (q, θ _i )}, and each bidder device uses the quality q _i obtained in the quality calculation procedure for public key cryptography. A quality encryption procedure for encryption at Enc, a price calculation procedure for each bidder device to obtain a function value b _i of the function q _i obtained in the quality calculation procedure, and each bidder device to For the function value b _i obtained in the price calculation procedure, the element c _{j, i} = E (1) (j = 1, 2,..., b _i ) and element c _{j, i} = E (z) (j = b _i +1, b _i +2,..., p) A price encryption procedure for generating a ciphertext string C (b _i ), and a cipher quality Enc (q _i ) encrypted by the bidder device in the quality encryption procedure and the price encryption procedure Declaration information transmission procedure for transmitting the ciphertext string C (b _i ) to the bidder apparatus on the buyer side, the cipher quality Enc (q _i ) and the ciphertext string transmitted by the bidder apparatus by the bidder apparatus. associates the reported information reception procedure of receiving the C (b _i), the bid opening's device encryption quality Enc received in the declared information reception procedure (q _i) and encryption Bunretsu C (b _i) to the seller i Declaration information registration procedure to be stored in the declaration information storage means, and the bid opening Device performs j-th element _{c j, i} integration of the declared information storage means each cryptographic Bunretsu stored in C _{(b i),} component product ^{_{c j = E (z n (}} j)) (n (J) is an element product calculation procedure for obtaining the number of bidders bidding with a function value greater than or equal to j) and n (b using the element product c _j obtained by the bidder device in the element product calculation procedure. _2nd ) is a value of 2 or more and n (b _2nd +1) is 1 or less, a next-point price calculation procedure for obtaining a function value b _2nd , and each of the ciphertext strings stored by the bid opener device in the declaration information storage means The element c _{x, i} (i = 1 to N) is decrypted (x represents b _2nd +1, and the same applies hereinafter), and the seller i _1st corresponding to the element c _{x, 1st} whose result is z is awarded The successful bidder determination procedure to be determined by the bidder, and the bidder device is recorded in the report information storage means. Quality decoding procedure for decoding the encrypted quality Enc (qi) that corresponds to the seller i _1st determined in the successful bidder determination procedure that is, the bid opening's apparatus decoded quality q _1st and the in the quality decoding procedure A reward calculation procedure for calculating the reward of seller i _1st by calculating {V (q _1st ) −b _2nd } using function value b _2nd obtained in the runner-up price calculation procedure; The seller i _1st determined in the bidder determination procedure is disclosed as a successful bidder, and the successful bid information disclosure procedure is disclosed in which the reward determined in the reward calculation procedure is disclosed as the successful bidder's reward.

An electronic procurement bidding system according to the present invention includes an electronic procurement bidding system including a bidder device on each seller i (i = 1 to N) side and a bidder device on a buyer side, and performs bidding based on price and quality. The quality calculation means for obtaining the quality q _i that maximizes the function {V (q) −c (q, θ _i )} in which the bidder apparatus on the side of the seller i depends on the type θ _{i of the} seller i and the quality q is a variable. When a price calculating means for calculating a function value b _i of the function of the quality q _i obtained by the quality calculation means, the function value b _i obtained by the quality q _i and the price calculating means is determined by the quality calculation unit Declaration information transmission means for transmitting to the bid opener device, and the bid opener device stores the quality q _i and the function value b _i of the seller i in association with the seller i, Sent by bidder device And reporting information receiving means for receiving the quality q _i and function values b _i, stores the quality q _i and the function value b _i is received by the reporting information receiving means to said return information storage means in association with the seller i Corresponding to the maximum function value b _i stored in the declaration information storage means, the successful bid information extraction means for extracting the seller i _1st having the maximum function value b _i from the declaration information storage means, Remuneration calculating means for calculating the reward of seller i _1st by using {q (q _1st ) −b _2nd } using quality q _1st and second largest function value b _2nd , and the successful bid information extracting means And disclosing the seller i _1st to be taken out as a successful bidder, and having a successful bid information disclosing means for disclosing the reward required by the reward calculating means as the reward of the successful bidder. It is characterized by.

The electronic procurement bidding system of the present invention includes a bidder device on each seller i (i = 1 to N) side and a bidder device on the buyer side, and the public key encryption E and ciphertext equally satisfying homomorphism. In an electronic procurement bidding system that publishes a number z other than 1 in a possible range and a bid price list P = {1, 2,..., P} and performs bidding based on price and quality, the seller i side Quality calculating means for obtaining a quality q _i that maximizes a function {V (q) −c (q, θ _i )} in which the bidder apparatus depends on the type θ _{i of the} seller i and uses the quality q as a variable; Quality encryption means for encrypting the quality q _i obtained by the operation means with public key encryption Enc, price calculation means for obtaining the function value b _{i of the} function of the quality q _i obtained by the quality operation means, element c to function value b _i obtained by price calculating means _{, I = E (1) (} j = 1,2, ···, b i) and element _{c j, i = E (z} ) (j = b i + 1, b i +2, ···, p) and Price encryption means for generating ciphertext string C (b _i ) as elements, cipher quality Enc (q _i ) encrypted by the quality encryption means, and ciphertext string generated by the price encryption means Declaration information transmission means for transmitting C (b _i ) to the bidder device, and the bidder device associates the seller i with the encryption quality Enc (q _i ) and the ciphertext string C of the seller i. and reporting information storage means for storing (b _i), and reporting information receiving means for receiving the encrypted quality Enc sent (q _i) and encryption Bunretsu C (b _i) by each said bidder apparatus, said reporting information cryptographic quality Enc received by the receiving means _{(q i)} and encryption Bunretsu C (b ) And reporting information registering means for storing in said reporting information storage means in association with the seller i, said j-th element c _j of reporting information storage means each cryptographic Bunretsu stored in C (b _{i), i} Element product calculation means for obtaining element product c _j = E (z ^{n (j)} ) (where n (j) is the number of bidders bidding with a function value equal to or greater than j), and the element product calculation means The next-point price calculation means for obtaining a function value b _2nd in which n (b _2nd ) is 2 or more and n (b _2nd +1) is 1 or less using the element product c _j obtained by Each element c _{x, i} (i = 1 to N) of the stored ciphertext string is decrypted (x represents b _2nd +1, and the same applies hereinafter), and the element c _x, and the successful bidder determination means for determining a seller i _1st corresponding to the _1st to the highest bidder, the monkey Quality decryption means for decrypting the encrypted quality Enc (qi) corresponding to the seller i _1st determined by the successful bidder determination means stored in the notification information storage means, the quality q _1st decrypted by the quality decryption means, and Using the function value b _2nd obtained by the runner-up price calculating means, the reward calculating means for calculating the reward of the seller i _1st by calculating {V (q _1st ) −b _2nd }, and the winning bidder determining means The seller i _1st is disclosed as a successful bidder, and a successful bid information disclosing means for disclosing the reward calculated by the reward calculating means as the reward of the successful bidder is provided.

The electronic procurement bidding program of the present invention uses a function {V (q) −c depending on the type θ _{i of the} seller i and a quality q as a variable in a computer as a bidder apparatus on the seller i (i = 1 to N) side. A quality calculation procedure for obtaining a quality q _i that maximizes (q, θ _i )}, a price calculation procedure for obtaining a function value b _i of the function of the quality q _i obtained in the quality calculation procedure obtained by the computer, and a computer And a reporting information transmission procedure for transmitting the quality q _i obtained in the quality computation procedure and the function value b _i obtained in the price computation procedure to a computer as a bidder device on the buyer side. And

In the electronic procurement bidding program of the present invention, the quality q _i and the function value b _i transmitted to the computer as the bidder apparatus on the buyer side by the computer as the bidder apparatus on each seller i (i = 1 to N) side are used. A declaration information receiving procedure to be received, a declaration information registration procedure in which the computer stores the quality q _i and the function value b _i received in the declaration information reception procedure in association with seller i in the declaration information storage means; The successful bid information extraction procedure for extracting the seller i _1st having the maximum function value b _i from the information storage means, the quality q _1st corresponding to the maximum function value b _i stored in the declaration information storage means in the computer and the second and rewards calculation procedure to determine by calculating the rewards large function value _{b 2nd} to utilize seller _{i 1st} value _{{V (q 1st) -b 2nd} } With publish seller i _1st extracted in the bid information extraction procedure to the computer as a successful bidder, a bid information published procedures to publish reward obtained as a reward for successful bidder in the compensation algorithm, that is the execution Features.

The electronic procurement bidding program of the present invention includes a public key encryption E satisfying homomorphism, a number z other than 1 within a range that can be a ciphertext, and a bid price list P = {1, 2,..., P }, And a function {V (q) −c (q) depending on the type θ _{i of the} seller i and the quality q as a variable in a computer as a bidder device on the seller i (i = 1 to N) side. , Θ _i )} that maximizes quality q _i , a quality encryption procedure that encrypts the quality q _i obtained in the quality computation procedure in the computer with the public key encryption Enc, the quality function value b _i Request price calculation procedure and the element to function value b _i determined in the price calculation procedure in the computer c _j of the function of the quality q _i determined in operation _{steps, i = E} ( 1) (j = 1,2, ··· , b ) And elements _{c j, i = E (z} ) (j = b i + 1, b i +2, ···, and price encryption procedure to generate the encryption Bunretsu C _{(b i)} to the p) elements, The encryption quality Enc (q _i ) encrypted in the quality encryption procedure and the ciphertext string C (b _i ) generated in the price encryption procedure are transmitted to the computer to the computer as the bidder device on the buyer side And a reporting information transmission procedure.

The electronic procurement bidding program of the present invention includes a public key encryption E satisfying homomorphism, a number z other than 1 within a range that can be a ciphertext, and a bid price list P = {1, 2,..., P } And the cipher quality Enc (q _i ) and ciphertext string transmitted by the computer as the bidder device on each seller i (i = 1 to N) side to the computer as the bidder device on the buyer side Declaration information reception procedure for receiving C (b _i ), and the encryption information Enc (q _i ) and ciphertext string C (b _i ) received in the declaration information reception procedure are associated with seller i in the computer. The registration information registration procedure to be stored in the means and the j-th element c _{j, i} of each ciphertext string C (b _i ) stored in the declaration information storage means in the computer are integrated, and the element product c _j = ^{E (z n (j))} ( (J) is an element product operation procedure for determining the number) of bidders who bid above function value j, by using the element product c _j determined at the element product operation procedure on the computer n (b _2nd) The next point price calculation procedure for obtaining a function value b _2nd that is 2 or more and n (b _2nd +1) is 1 or less, and each element c _{x, i} () of the ciphertext string stored in the declaration information storage means in the computer i = 1 to N) (x represents b _2nd +1, the same applies hereinafter), and the successful bidder determines the seller i _1st corresponding to the element c _{x, 1st} whose result is z as the winning bidder and determination procedure, the procedure quality decoding for decoding the encrypted quality Enc (qi) that corresponds to the seller i _1st determined in the successful bidder determination procedure stored in the declared information storage means to a computer, the quality computer Compensation determined by calculating the compensation of decoded quality _{q 1st} and the runner-up prices by using the function value _{b 2nd} determined in algorithm seller _{i 1st {V (q 1st)} -b 2nd} in Patent Procedure A calculation procedure, and a successful bid information disclosure procedure for publishing the seller i _1st determined in the successful bidder determination procedure as a successful bidder to a computer and releasing the reward determined in the reward calculation procedure as a successful bidder reward. It is made to perform.

  According to the present invention, it is possible to realize a procurement bid while keeping the type secret concealed by sending the quality and cost information obtained based on the type from the seller side to the buyer side.

<< First Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. However, in the first embodiment, the quality obtained based on the type and the information corresponding to the cost are reported instead of the type reported in Non-Patent Document 1, and the same bidding result as in Non-Patent Document 1 is used. Is what you get.

  First, the system configuration of the electronic procurement bidding system in the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a system configuration diagram showing a system configuration of the electronic procurement system according to the first embodiment.

  As shown in FIG. 1, the electronic procurement system 1 includes a bidder apparatus 2 (2-1, 2-2,..., 2-N) provided on a seller (bidder) side and a buyer (bidder) side. The bidder device 3 is provided with each bidder device 2 and the bidder device 3 are connected so as to be able to exchange data. However, it is assumed that the seller i (i = 1, 2,..., N) uses the bidder apparatus 2-i, and the bidder apparatuses 2-1, 2-2,. The configuration is the same.

Next, functions of the bidder apparatus 2-i (i = 1, 2,..., N) in FIG. 1 will be described with reference to FIG. FIG. 2 is a functional block diagram showing a functional configuration of the bidder apparatus 2-i of FIG.
As shown in FIG. 2, the bidder apparatus 2-i has units that function as a function storage unit 21, a type input unit 22, a quality calculation unit 23, a price calculation unit 24, and a report information transmission unit 25. .

The function storage unit 21 stores a function b (q, θ) (= V (q) −c (q, θ)) for each type θ. The type θ is information such as a manufacturing cost that determines a function c (q, θ) of the manufacturing cost of a product of quality q, and is important confidential information of the seller. The function V (q) is a known function, and the same function is used in all bidder apparatuses 2 and bid opener apparatuses 3. The function c (q, θ) is the manufacturing cost of a product of seller quality q and depends on the seller's type θ.
FIG. 3 is a diagram showing an example of the function storage unit 21, and there are “type” and “cost function” as fields. The function storage unit 21 stores a plurality of types θ of functions b (q, θ).

The type input unit 22 is a device for the seller i who uses the bidder apparatus 2-i to input his type θ _i in the current bid, and the type input unit 22 performs quality calculation on the input type θ _i. It outputs to each of the part 23 and the price calculating part 24.
The quality calculation unit 23 extracts from the function storage unit 21 a function b _i (q, θ _i ) in which the value of the field “type” matches the type θ _i input from the type input unit 22, and extracts the function b _i ( The quality q _i that maximizes q, θ _i ) (= V (q) −c (q, θ _i )) is obtained. The quality calculation unit 23 outputs the obtained quality q _i to the price calculation unit 24 and the reporting information transmission unit 25, respectively.

The price calculation unit 24 extracts from the function storage unit 21 a function b _i (q, θ _i ) in which the value of the field “type” matches the type θ _i input from the type input unit 22. Then, the price calculation unit 24 substitutes the quality q _i input from the quality calculation unit 23 into the extracted function b _i (q, θ _i ) (= V (q) −c (q, θ _i )). The value (function value) b _i of the function b _i (q _i , θ _i ) (= V (q _i ) −c (q _i , θ _i )) is obtained. The price calculation unit 24 outputs the obtained function value b _i to the reporting information transmission unit 25.
The reporting information transmission unit 25 includes information indicating the seller i who uses the bidder apparatus 2-i, the quality q _i input from the quality calculation unit 23, and the function value b _i input from the price calculation unit 24. Is transmitted to the bid opener device 3.

Further, functions of the bid opener device 3 of FIG. 1 will be described with reference to FIG. FIG. 4 is a functional block diagram showing a functional configuration of the bid opener device 3 of FIG.
As shown in FIG. 4, the bid opener device 3 includes a reporting information storage unit 31, a reporting information receiving unit 32, a reporting information registration unit 33, a successful bidder information extracting unit 34, a runner-information extracting unit 35, and a reward calculating unit 36. , And each unit functioning as the successful bid information disclosure unit 37.

The reporting information storage unit 31 stores quality reported by the seller for each seller and a function value corresponding to the price, an example of which is shown in FIG. FIG. 5 is a diagram illustrating an example of the report information storage unit 31. As shown in FIG. 5, fields of the report information storage unit 31 include “seller”, “quality”, and “function value”.
The reporting information receiving unit 32 receives information indicating the seller i, quality q _i and function value b _i transmitted by the bidder apparatus 2-i (i = 1, 2,..., N), and receives the information. Each piece of information is output to the reporting information registration unit 33.
The reporting information registration unit 33 stores the information indicating the seller i, the quality q _i, and the function value b _i input from the reporting information receiving unit 32 in the reporting information storage unit 31.

The successful bidder information extraction unit 34 refers to the stored contents of the report information storage unit 31 and extracts the seller i _1st and the quality q _1st having the maximum value of the field “function value” from the report information storage unit 31. The successful bidder information extraction unit 34 outputs the extracted seller i _1st to the successful bid information disclosure unit 37, and outputs the extracted quality q _1st to the reward calculation unit 36.
The runner-in information extraction unit 35 refers to the stored contents of the report information storage unit 31 and extracts the function value b _2nd having the second largest value of the field “function value” from the report information storage unit 31. The runner-up information extraction unit 35 outputs the extracted function value b _2nd to the reward calculation unit 36.

The reward calculation unit 36 uses the quality q _1st input from the successful bidder information extraction unit 34 and the function value b _2nd input from the runner-up information extraction unit 35 to calculate V (q _1st ) −b _2nd . Calculate the reward P. The reward calculation unit 36 outputs the calculated reward P to the successful bid information disclosure unit 37.
The successful bid information disclosure unit 37 displays the seller i _1st input from the successful bidder information extraction unit 34 as a successful bidder on the display unit included in the successful bid information disclosure unit 37 and the reward P input from the reward calculation unit 36 as a reward for the successful bidder Display as.

Furthermore, the flow of the electronic procurement bidding process performed in the electronic procurement bidding system 1 described above will be described with reference to FIGS.
FIG. 6 is a flowchart showing the flow of the electronic procurement bidding process executed by the bidder apparatus 2. First, a seller i who uses the bidder apparatus 2-i inputs his / her type θ _i using the type input unit 22. The quality calculation unit 23 determines whether or not the type θ _i is input based on the signal input from the type input unit 22 (step S101). If it is determined that the type θ _i is not input (S101: NO), the process returns to step S101. On the other hand, if it is determined that the type θ _i is input (S101: YES), the process proceeds to step S102.
The quality calculation unit 23 extracts from the function storage unit 21 a function b _i (q, θ _i ) in which the value of the field “type” matches the type θ _i input from the type input unit 22, and extracts the function b _i ( The quality q _i that maximizes q, θ _i ) is obtained (step S102).

Subsequently, the price calculation unit 24 extracts from the function storage unit 21 a function b _i (q, θ _i ) in which the value of the field “type” matches the type θ _i input from the type input unit 22. Then, the price calculation unit 24 calculates the function b _i (q _i , θ _i ) by substituting the quality q _i obtained in step S102 for the extracted function b _i (q, θ _i ), and calculates the function value. b _i is obtained (step S103).
The reporting information transmission unit 25 receives information indicating the seller i who uses the bidder apparatus 2-i, the quality q _i obtained in step S102, and the function value b _i obtained in step S103, the bidder apparatus. 3 (step S104).

FIG. 7 is a flowchart showing a flow of electronic procurement bidding processing (report information registration) executed by the bid opener apparatus 3.
First, the reporting information receiving unit 32 determines whether or not the information indicating the seller i, the quality q _i, and the function value b _i transmitted by the bidder apparatus 2-i have been received (step S201). If it is determined that each piece of information has not been received (S201: NO), the process returns to step S201. On the other hand, if it is determined that each information has been received (S201: YES), the process proceeds to step S202, and the reporting information registration unit 33 receives the information indicating the seller i received by the reporting information receiving unit 32 in step S201 and the quality q _i. And the function value b _i are stored in the report information storage unit 31 (step S202). Then, the process returns to step S201.

FIG. 8 is a flowchart showing the flow of the electronic procurement bidding process (determining the successful bidder) executed by the bid opener apparatus 3.
When the buyer receives the declaration information (seller i, quality q _i and function value b _i ) from each seller i and performs a predetermined operation, the successful bidder information extraction unit 34 refers to the stored contents of the declaration information storage unit 31. Then, the seller i _1st and the quality q _1st having the maximum value of the field “function value” are extracted from the reporting information storage unit 31 (step S301).
The runner-in information extraction unit 35 refers to the stored contents of the report information storage unit 31 and extracts the function value b _2nd having the second largest value of the field “function value” from the report information storage unit 31 (step S302).

The reward calculation unit 36 calculates V (q _1st ) −b _2nd by using the quality q _1st extracted in step S301 and the function value b _2nd extracted in step S302 to obtain the reward P (step S303).
The successful bid information disclosure unit 37 displays the seller i _1st taken out in step S301 as a successful bidder on the display unit included therein, and displays the reward P obtained in step S303 as a reward for the successful bidder (step S304). ).

Hereinafter, there are sellers 1 and 2, and a function b ₁ (q, θ ₁ ) = V (q) −c (q, θ ₁ ) = (q) ^1/2 −q / 4, a function b ₂ (q, θ ₂ ) = V (q) −c (q, θ ₂ ) = (q) ^1/2 −q / 2.
On the seller 1 side, the quality q ₁ that maximizes the function b ₁ (q, θ ₁ ) is “4”, and the function value b ₂ is “1” (= (4) ^1/2 -4/4). Sent to the bidder side.
On the seller 2 side, the quality q ₂ that maximizes the function b ₂ (q, θ ₂ ) is “1”, and the function value b ₂ is “1/2” (= (1) ^1/2 −1/2). This is sent to the bidder side.

On the bid opener side, the seller 1 with the largest function value becomes the winning bidder, and the reward P of the seller 1 who is the winning bidder is “3/2” (= (4) ^1/2 −1/2).
The utility of seller 1 is “1/2” (= P−c (q ₁ , θ ₁ ) = 3 / 2-4 / 4), and the utility of buyer is “1/2” (= V (4) −P ) = (4) ^1/2 −3/2).
According to the first embodiment described above, it is possible to realize a procurement bid that conceals the seller's type.

<< Second Embodiment >>
The second embodiment of the present invention will be described below with reference to the drawings.
First, the system configuration of the electronic procurement bidding system according to the second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a system configuration diagram illustrating a system configuration of the electronic procurement system according to the second embodiment.
As shown in FIG. 9, the electronic procurement system 6 includes a bidder device 7 (7-1, 7-2,..., 7-N) provided on the seller (bidder) side and a buyer (bidder) side. The bidder device 8 is provided, and each bidder device 7 and the bidder device 8 are connected so as to be able to exchange data. However, it is assumed that the seller i (i = 1, 2,..., N) uses the bidder apparatus 7-i, and the bidder apparatuses 7-1, 7-2,. The configuration is the same.

Next, functions of the bidder apparatus 7-i (i = 1, 2,..., N) in FIG. 9 will be described with reference to FIG. FIG. 10 is a functional block diagram showing a functional configuration of the bidder apparatus 7-i of FIG.
As shown in FIG. 10, the bidder apparatus 7-i includes a function storage unit 71, a type input unit 72, a quality calculation unit 73, a quality encryption unit 74, a price calculation unit 75, a price encryption unit 76, and a report information transmission unit. Each unit functions as 77.
The function storage unit 71 stores a function b (q, θ) (= V (q) −c (q, θ)) for each type θ as in the function storage unit 21 of FIG.

The type input unit 72 is a device for the seller i who uses the bidder apparatus 7-i to input his type θ _i in the current bid, and the type input unit 22 performs quality calculation on the input type θ _i. Output to each of the unit 73 and the price calculation unit 75.
Quality calculation unit 73 takes out the function b _{i (q, θ i)} the value of the type theta _i and field "type" input from the typing unit 72 matches the from the function storage unit 71, takes out the function b _i ( The quality q _i that maximizes q, θ _i ) (= V (q) −c (q, θ _i )) is obtained. The quality calculation unit 73 outputs the obtained quality q _i to each of the quality encryption unit 74 and the price calculation unit 75.
Quality encryption unit 74, creates a cryptographic quality Enc _{(q i)} by encrypting the quality _{q i} input from the quality calculating unit 73 in a public key encryption Enc, reporting information transmitting unit the encrypted quality Enc _{(q i)} Output to 77.

The price calculation unit 75 extracts from the function storage unit 71 a function b _i (q, θ _i ) in which the value of the field “type” matches the type θ _i input from the type input unit 22. The price calculation unit 75 then substitutes the quality q _i input from the quality calculation unit 73 into the extracted function b _i (q, θ _i ) (= V (q) −c (q, θ _i )). The value (function value) b _i of the function b _i (q _i , θ _i ) (= V (q _i ) −c (q _i , θ _i )) is obtained. The price calculation unit 75 outputs the obtained function value b _i to the price encryption unit 76.

Price encryption unit 76 generates a function value b _i input from the price calculating unit 75 encryption Bunretsu C (b _i), and outputs the generated cipher Bunretsu C (b _i) to the reporting information transmitting unit 77 .
The public key cipher E is a secure (IND-CPA) public key cipher that satisfies homomorphism (E (a) E (b) = E (ab)), such as ElGamal cipher. Further, it is assumed that a number z other than 1 in a range that can be a ciphertext equivalent and a bid price list P = {1, 2,..., P} are disclosed in advance and disclosed to the bidder apparatus in advance. The number z and the bid price list are stored in a storage device (not shown).
The price encryption unit 76 applies the function value b _i input from the price calculation unit 75 to the ciphertext string C (consisting of the elements c _{1, i} , c _{2, i} ,..., C _{p, i} shown below. b _i ) = (c _{1, i} , c _{2, i} ,..., c _{p, i} ) is generated. However,
c _{j, i} = E (z): j = 1, 2,..., b _i
c _{j, i} = E (1): j = b _i +1, b _i +2,..., p
It is.

The reporting information transmission unit 77 includes information indicating the seller i who uses the bidder apparatus 7-i, the encryption quality Enc (q _i ) input from the quality encryption unit 24, and the encryption input from the price encryption unit 76. The sentence string C (b _i ) is transmitted to the bid opener device 8.

Further, the function of the bid opener device 8 of FIG. 9 will be described with reference to FIG. FIG. 11 is a functional block diagram showing a functional configuration of the bid opener device 8 of FIG.
As shown in FIG. 11, the bid opener device 8 includes a report information storage unit 81, a report information receiving unit 82, a report information registration unit 83, an element product calculation unit 84, a division unit 85, a disturbance unit 86, a mixing unit 87, Each unit functions as a partial decryption unit 88, a determination unit 89, an element decryption unit 90, a successful bidder determination unit 91, an encryption quality extraction unit 92, a quality decryption unit 93, a reward calculation unit 94, and a successful bid information disclosure unit 95. Yes.

The reporting information storage unit 81 stores the encryption quality and ciphertext string reported by the seller for each seller, an example of which is shown in FIG. FIG. 12 is a diagram illustrating an example of the report information storage unit 81. As shown in FIG. 12, the fields of the report information storage unit 81 include “seller”, “encrypted quality”, and “ciphertext string”.
The reporting information receiving unit 82 includes information indicating the seller i transmitted by the bidder apparatus 7-i (i = 1, 2,..., N), the encryption quality Enc (q _i ), and the ciphertext string C (b _i ) and outputs the received information to the reporting information registration unit 83.
The reporting information registration unit 83 stores the information indicating the seller i, the encryption quality Enc (q _i ), and the ciphertext string C (b _i ) input from the reporting information receiving unit 82 in the reporting information storage unit 81.

The element product calculation unit 84 refers to the storage contents of the report information storage unit 81 and adds (c _{j, 1} c _{j, 2,} ...) J-th element c _{j, i} of each ciphertext string C (b _i ). C _{j, N} ), the element product c _j (= c _{j, 1} c _{j, 2} ... C _{j, N} ) is obtained, and the obtained element product c _j is output to the division unit 85. However, due to the homomorphism of the public key cryptography E, c _j = E (z ^{n (j)} ). Note that n (j) = # {1 | j ≦ p _i } is the number of bidders who bid at a price of j or higher. Note that j = p / 2, p / 4, p / 8,...

The division unit 85 divides the element product c _j input from the element product calculation unit 84 by each of E (1), E (z), and E (z ² ), and the division result m _{j, 1} (= c _j / E (1)), m _{j, 2} (= c _j / E (z)), m _{j, 3} (= c _j / E (z ² )) are obtained and output to the disturbance unit 86.
The disturbing unit 86 calculates the random number multiplication result mr _{j, 1} (= m _{j, 1} ^r1 ) by raising the division result m _{j, 1} input from the division unit 85 to the random number r1. The disturbance unit 86 calculates the random number multiplication result mr _{j, 2} (= m _{j, 2} ^r2 ) by dividing the division result m _{j, 2} input from the division unit 85 to the random number r ₂ . The disturbing unit 86 calculates the random number multiplication result mr _{j, 3} (= m _{j, 3} ^r3 ) by raising the division result m _{j, 3} input from the division unit 85 to the random number r3. Then, the disturbance unit 86 outputs the obtained random number multiplication results mr _{j, 1} , mr _{j, 2} , mr _{j, 3} to the mixing unit 87.

The mixing unit 87 mixes the random number multiplication results mr _{j, 1} , mr _{j, 2} , mr _{j, 3} input from the disturbance unit 86 (reorders the order and randomizes the ciphertext), and then proceeds to the partial decryption unit 88. Output.
The partial decryption unit 88 decrypts the random number multiplication results mr _{j, 1} , mr _{j, 2} , mr _{j, 3} mixed from the mixing unit 87 and outputs the decryption results to the determination unit 89.
The determination unit 89 determines whether “1” is included in the decoding result input from the partial decoding unit 88. If there is an item that is “1”, it is determined that the decryption D (c _j ) ε {1, z, z ² } is satisfied, and if there is no item that is “1”, it is determined that the above function is not satisfied. Satisfying j determines a function value _{b 2nd} and thereby _{n (b 2nd)} is larger function value _{b 2nd} value to the second _{n (b} 2nd +1) is 1 or less at more is required.
In addition, the division part 85, the disturbance part 86, the mixing part 87, the partial decoding part 88, and the judgment part 89 are equivalent to a runner-up price calculation means.
Note that the processes of the element product calculation unit 84, the division unit 85, the disturbance unit 86, the mixing unit 87, the partial decoding unit 88, and the determination unit 89 are repeated log (p) times.

The element decoding unit 90 decodes the elements c _{x, 1} , c _{x, 2} ,..., C _{x, N} and decodes D (c _{x, 1} ), D (c _{x, 2} ),. D (c _{x, N} ) is output to the successful bidder determination unit 91. However, x represents b _2nd +1 and is the same in the following.
Successful bidder determination unit 91 decodes _D (c _{x, 1)} is input from the element decoding unit _{90, D (c x, 2} ), ···, D (c x, N) among, D _{(c x , 1st} ) = z, the seller i _1st is determined as the successful bidder, and the seller i _1st is output to the encryption quality extraction unit 92.
Encryption quality extraction unit 92 extracts the encryption quality Enc the values match the seller _{i 1st} and field inputted from the successful bidder determination section 91 "Seller" _{(q 1st),} extracted cryptographic quality Enc a _{(q 1st)} Quality The data is output to the decoding unit 93.
Quality decoding unit 93 obtains a quality _{q 1st} decrypts the encrypted quality Enc inputted from the encryption quality extraction unit 92 _{(q 1st),} and outputs the quality _{q 1st} determined to reward calculation unit 94.

The reward calculation unit 94 calculates V (q _1st ) −b _2nd using the quality q _1st input from the quality decryption unit 93 and the function value b _2nd input from the determination unit 89 to calculate the reward P. The calculated reward P is output to the successful bid information disclosure unit 95.
The successful bid information disclosure unit 95 displays the seller i _1st input from the successful bidder determination unit 91 as a successful bidder on the display unit included therein, and the reward P input from the reward calculation unit 94 as a reward for the successful bidder. indicate.

Further, the flow of the electronic procurement bidding process performed in the electronic procurement bidding system 6 described above will be described with reference to FIGS.
FIG. 13 is a flowchart showing the flow of the electronic procurement bidding process executed by the bidder apparatus 7. First, the seller i who uses the bidder apparatus 7-i inputs his / her type θ _i using the type input unit 72. The quality calculation unit 73 determines whether or not the type θ _i is input based on the signal input from the type input unit 22 (step S401). If it is determined that the type θ _i is not input (S401: NO), the process returns to step S401. On the other hand, if it is determined that the type θ _i is input (S401: YES), the process proceeds to step S402.
Quality calculation unit 73 takes out the function b _{i (q, θ i)} the value of the type theta _i and field "type" input from the typing unit 72 matches the from the function storage unit 71, takes out the function b _i ( Quality q _i that maximizes q, θ _i ) is obtained (step S402).
The quality encryption unit 74 encrypts the quality q _i obtained in step S402 with the public key encryption Enc (step S403).

The price calculation unit 75 extracts from the function storage unit 71 a function b _i (q, θ _i ) in which the value of the field “type” matches the type θ _i input from the type input unit 22. Then, the price calculation unit 75 substitutes the quality q _i obtained in step S402 for the extracted function b _i (q, θ _i ), and the value (function value) b _{i of the} function b _i (q _i , θ _i ). Is obtained (step S404).
The price encryption unit 76 uses the ciphertext string C (b _i) composed of the elements c _{1, i} , c _{2, i} ,..., C _{p, i} shown below for the function value b _i obtained in step S404. ) = (C _{1, i} , c _{2, i} ,..., C _{p, i} ). However,
c _{j, i} = E (z): j = 1, 2,..., b _i
c _{j, i} = E (1): j = b _i +1, b _i +2,..., p
(Step S405).

The reporting information transmission unit 77 includes information indicating the seller i who uses the bidder apparatus 7-i, the cipher quality Enc (q _i ) obtained in step S403, and the ciphertext string C (b obtained in step S405. _i ) is transmitted to the bid opener device 8 (step S406).

FIG. 14 is a flowchart showing a flow of electronic procurement bidding processing (report information registration) executed by the bid opener device 8.
First, the reporting information receiving unit 82 determines whether or not the information indicating the seller i, the cipher quality Enc (q _i ), and the ciphertext string C (b _i ) transmitted by the bidder apparatus 8-i have been received. (Step S501). If it is determined that each piece of information has not been received (S501: NO), the process returns to step S501. On the other hand, if it is determined that each information has been received (S501: YES), the process proceeds to step S502, and the reporting information registration unit 83 receives the information indicating the seller i received by the reporting information receiving unit 82 in step S501 and the encryption quality Enc. (Q _i ) and the ciphertext string C (b _i ) are stored in the report information storage unit 81 (step S502). Then, the process returns to step S501.

FIG. 15 is a flowchart showing the flow of the electronic procurement bidding process (determining the successful bidder) executed by the bid opener device 8.
When the buyer receives the declaration information (seller i, encryption quality Enc (q _i ), ciphertext string C (b _i )) from each seller i and performs a predetermined operation, the element product operation unit 84 stores the declaration information. Referring to the stored contents of the part 81, the j-th element c _{j, i} of each ciphertext string C (b _i ) is integrated (c _{j, 1} c _{j, 2} ... C _{j, N} ) A product c _j (= c _{j, 1} c _{j, 2} ... C _{j, N} ) is obtained (step S601).

The division unit 85 divides the element product c _j input from the element product calculation unit 84 by each of E (1), E (z), and E (z ² ), and the disturbance unit 86 outputs each division result. Each of m _{j, 1} , m _{j, 2} , m _{j, 3} is multiplied by a random number r 1, a random number r ₂ , and a random number r ₃ to obtain a random number multiplication result mr _{j, 1} , mr _{j, 2} , mr _{j, 3} . The mixing unit 87 rearranges the random number multiplication results mr _{j, 1} , mr _{j, 2} , mr _{j, 3} . The partial decoding unit 88 decodes the random number multiplication results mr _{j, 1} , mr _{j, 2} , mr _{j, 3} mixed by the mixing unit 87. The determination unit 89 determines whether “1” is included in the decoding result by the partial decoding unit 88. If there is an item that is “1”, it is determined that the decryption D (c _j ) ε {1, z, z ² } is satisfied, and if there is no item that is “1”, it is determined that the above function is not satisfied. Satisfying j determines a function value _{b 2nd} and thereby _{n (b 2nd)} is larger function value _{b 2nd} value to the second _{n (b} 2nd +1) is 1 or less at more is determined (Step S602) .
The processes in steps S601 and S602 are repeated log (p) times in the order of j = p / 2, p / 4, p / 8,.

The element decryption unit 90 decrypts the elements c _{x, 1} , c _{x, 2} ,..., C _{x, N} , and the successful bidder determination unit 91 decrypts the decryption results D (c _{x, 1} ), D Among the (c _{x, 2} ),..., D (c _{x, N} ), the seller i _1st with D (c _{x, 1st} ) = z is determined as the winning bidder (step S603).
The encryption quality extraction unit 92 extracts the encryption quality Enc (q _1st ) in which the value of the field “seller” matches the seller i _1st input from the successful bidder determination unit 91, and the quality decryption unit 93 extracts the extracted encryption quality Enc (q _1st ) is decoded to obtain quality q _1st (step S604).

The reward calculation unit 94 calculates V (q _1st ) −b _2nd using the quality q _1st obtained in step S604 and the function value b _2nd obtained in step S602 to obtain the reward P (step S605).
The successful bid information disclosure unit 95 displays the seller i _1st determined in step S603 as a successful bidder on the display unit included therein, and displays the reward P obtained in step S605 as a reward for the successful bidder (step S606). ).
According to the second embodiment described above, it is possible to realize a procurement bid not only concealing the seller's type but also concealing the information corresponding to the seller's quality and price.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  It should be noted that a program for realizing the functions of each processing unit described above is recorded on a computer-readable recording medium, the program recorded on the recording medium is read into a computer system, and executed to execute the above-described various processes. You may go. The “computer system” here includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system provided with a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in the computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

The system block diagram of the electronic procurement system of the 1st Embodiment of this invention. The functional block diagram which shows the function structure of the bidder apparatus of FIG. The figure which shows an example of the function memory | storage part of FIG. The functional block diagram which shows the function structure of the bid opener apparatus of FIG. The figure which shows an example of the report information storage part of FIG. The flowchart which shows the flow of the process of the electronic procurement bid which the bidder apparatus of FIG. 1 performs. It is a flowchart which shows the flow of the process of the electronic procurement bid which the bid opener apparatus of FIG. 1 performs. It is a flowchart which shows the flow of the process of the electronic procurement bid which the bid opener apparatus of FIG. 1 performs. The system block diagram of the electronic procurement system of the 2nd Embodiment of this invention. The functional block diagram which shows the function structure of the bidder apparatus of FIG. The functional block diagram which shows the function structure of the bidder apparatus of FIG. The figure which shows an example of the report information storage part of FIG. The flowchart which shows the flow of the process of the electronic procurement bid which the bidder apparatus of FIG. 9 performs. It is a flowchart which shows the flow of the process of the electronic procurement bid which the bid opener apparatus of FIG. 9 performs. It is a flowchart which shows the flow of the process of the electronic procurement bid which the bid opener apparatus of FIG. 9 performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic procurement system 2 Bidder apparatus 3 Bidder apparatus 21 Function storage part 22 Type input part 23 Quality calculation part 24 Price calculation part 25 Declaration information transmission part 31 Declaration information storage part 32 Declaration information reception part 33 Declaration information registration part 34 Successful bid Information extraction part 35 runner information extraction part 36 reward calculation part 37 successful bid information disclosure part

Claims (4)

In e-procurement bidding method for bidding based on price and quality,
Public key cipher E satisfying homomorphism, number z other than 1 in a range that can be a ciphertext, and bid price list P = {1, 2,..., P}
Each seller i (i = 1 to N) side of the bidders apparatus seller i type function to theta _i-dependent variable quality q of {V (q) -c (q , θ i)} to maximize A quality calculation procedure for obtaining quality q _i ;
Each of the bidder apparatuses encrypts the quality q _i obtained in the quality calculation procedure with a public key encryption Enc,
A price calculation procedure for each bidder device to obtain a function value b _i of the function of the quality q _i determined in the quality calculation procedure;
The element c _{j, i} = E (1) (j = 1, 2,..., B _i ) and the element c _{j, i with} respect to the function value b _i obtained by the bidder device in the price calculation procedure. A price encryption procedure for generating a ciphertext sequence C (b _i ) whose elements are = E (z) (j = b _i +1, b _i +2,..., P);
The bidder apparatus transmits the encrypted quality Enc (q _i ) encrypted in the quality encryption procedure and the ciphertext string C (b _i ) generated in the price encryption procedure to the bidder apparatus on the buyer side. Procedure for sending declaration information,
Declaration information reception procedure for receiving the cipher quality Enc (q _i ) and ciphertext string C (b _i ) transmitted by each bidder device by the bid opener device;
Declaration information registration procedure for storing the cipher quality Enc (q _i ) and ciphertext string C (b _i ) received by the bid opener device in the declaration information reception procedure in association with seller i in the declaration information storage means;
The bid opener device adds up the j-th element c _{j, i} of each ciphertext string C (b _i ) stored in the return information storage means, and the element product c _j = E (z ^{n (j)} ) (N (j) is the number of bidders who bid with a function value equal to or greater than j)
Next point where the bid opener device uses the element product c _j obtained in the element product calculation procedure to obtain a function value b _2nd in which n (b _2nd ) is 2 or more and n (b _2nd +1) is 1 or less Price calculation procedure,
The bid opener device decrypts each element c _{x, i} (i = 1 to N) of the ciphertext string stored in the return information storage means (x represents b _2nd +1, and the same applies hereinafter) A successful bidder determination procedure for determining a seller i _1st corresponding to an element c _{x, 1st} whose result is z as a successful bidder;
A quality decryption procedure in which the bid opener device decrypts the encryption quality Enc (qi) corresponding to the seller i _1st determined in the successful bidder determination procedure stored in the reporting information storage means;
The bidder device uses the quality q _1st decrypted in the quality decryption procedure and the function value b _2nd obtained in the next price calculation procedure to reward the seller i _1st {V (q _1st ) −b _2nd } To calculate the reward to be calculated,
A bid information disclosure procedure in which the bidder device discloses the seller i _1st determined in the successful bidder determination procedure as a successful bidder, and discloses the reward determined in the reward calculation procedure as a reward for the successful bidder;
An electronic procurement bidding method characterized by comprising: A number z other than 1 in a range that can be a common part of ciphertext, public key cipher E having a homomorphism, and a tender device on each seller i (i = 1 to N) side and a bidder device on the buyer side , And an electronic procurement bidding system that publishes a bid price list P = {1, 2,..., P} and performs bidding based on price and quality.
The bidder device on the seller i side calculates the quality q _i that maximizes the function {V (q) −c (q, θ _i )} having the quality q as a variable depending on the type θ _{i of the} seller i. Means,
Quality encryption means for encrypting the quality q _i required by the quality calculation means with a public key encryption Enc;
Price calculating means for obtaining a function value b _i of the function of the quality q _i obtained by the quality calculating means;
Element c _{j, i} = E (1) (j = 1, 2,..., B _i ) and element c _{j, i} = E (z) (j) for the function value b _i obtained by the price calculation means = Price encryption means for generating a ciphertext string C (b _i ) whose elements are = b _i +1, b _i +2,.
Declaration information transmission means for transmitting the cipher quality Enc (q _i ) encrypted by the quality encryption means and the ciphertext string C (b _i ) generated by the price encryption means to the bidder device;
With
The bid opener device is
Declaration information storage means for storing the encryption quality Enc (q _i ) and ciphertext string C (b _i ) of the seller i in association with the seller i;
Declaration information receiving means for receiving the cipher quality Enc (q _i ) and the ciphertext string C (b _i ) transmitted by each of the bidder apparatuses;
Declaration information registration means for storing the encryption quality Enc (q _i ) and ciphertext string C (b _i ) received by the declaration information receiving means in association with seller i in the declaration information storage means;
The j-th element c _{j, i} of each ciphertext string C (b _i ) stored in the reporting information storage means is integrated, and the element product c _j = E (z ^{n (j)} ) (n (j ) Is an element product calculating means for obtaining the number of bidders bidding with a function value of j or more,
Using the element product c _j obtained by the element product calculating means, a point price calculating means for obtaining a function value b _2nd in which n (b _2nd ) is 2 or more and n (b _2nd +1) is 1 or less;
Each element c _{x, i} (i = 1 to N) of the ciphertext string stored in the report information storage means is decrypted (x represents b _2nd +1, and the same applies hereinafter), and the result is z A successful bidder determination means for determining a seller i _1st corresponding to the element c _{x, 1st} to be a successful bidder;
Quality decryption means for decrypting the encryption quality Enc (qi) corresponding to the seller i _1st determined by the successful bidder determination means stored in the declaration information storage means;
Using the quality q _1st decrypted by the quality decryption means and the function value b _2nd obtained by the next price calculation means, the reward of the seller i _1st is obtained by computing {V (q _1st ) −b _2nd }. Reward calculation means;
A successful bid information disclosing means for disclosing seller i _1st determined by the successful bidder determining means as a successful bidder, and disclosing the remuneration required by the remuneration calculating means as the reward of the successful bidder;
An electronic procurement bidding system characterized by comprising: A number z other than 1 in a range that can be a common part of ciphertext, public key cipher E having a homomorphism , and a tender device on each seller i (i = 1 to N) side and a bidder device on the buyer side , And a bid price list P = {1, 2,..., P}, and an electronic device for causing the computer on the bidder apparatus in the electronic procurement bidding system to perform bidding based on price and quality to perform electronic procurement bidding A procurement bidding program,
Seller i (i = 1 to N) side of the bidders dependent on the computer on the device type theta _i of the seller i is a function whose variable is the quality q {V (q) -c ( q, θ i)} a A quality calculation procedure for determining the quality q _i to be maximized;
Quality encryption procedure to encrypt the quality q _i in public key encryption Enc determined in the quality algorithm to the computer,
And price calculation procedure for determining the function value b _i of the function of the quality q _i determined in the quality algorithm to the computer,
The function value obtained in the price calculation steps _{b i} with respect to element _c j in the computer, i = E (1) ( j = 1,2, ···, b i) and element _{c j,} i = E ( z) a price encryption procedure for generating a ciphertext sequence C (b _i ) whose elements are (j = b _i +1, b _i +2,..., p);
Declaration of transmitting said quality encryption procedure encrypted encryption quality Enc in the computer (q _i) and the price encryption procedure encrypted generated in Bunretsu C (b _i) of the buyer side to the tender opening's equipment Information transmission procedure;
An electronic procurement bidding program characterized in that A number z other than 1 in a range that can be a common part of ciphertext, public key cipher E having a homomorphism , and a tender device on each seller i (i = 1 to N) side and a bidder device on the buyer side , And a bid price list P = {1, 2,..., P}, and an electronic system for causing the computer on the bidder apparatus to perform electronic procurement bidding in an electronic procurement bidding system that performs bidding based on price and quality A procurement bidding program,
Buyer of tender opening's to the computer on the device each seller i (i = 1~N) transmitting Therefore bidder equipment side cryptographic quality Enc _{(q i)} and receives the encryption Bunretsu C _{(b i)} To receive the report information,
And reporting information registration procedure for storing cryptographic quality Enc which receives the (q _i) and encryption Bunretsu C (b _i) the reporting information storage means in association with the seller i in the return information received instructions to the computer,
Performs j-th element _{c j, i} integration of the declared information storage means each cryptographic Bunretsu stored in C _{(b i)} to said computer, element product ^{_{c j = E (z n (}} j)) ( n (j) is the number of bidders bidding with a function value of j or more)
Runner-up price calculation for obtaining the element using the element product _{c j} determined in product operation steps _{n (b 2nd)} is _n 2 or more _(b 2nd +1) is 1 or less function value _{b 2nd} to the computer Procedure and
The computer decrypts each element c _{x, i} (i = 1 to N) of the ciphertext string stored in the declaration information storage means (x represents b _2nd +1, and the same applies hereinafter), A successful bidder determination procedure for determining a seller i _1st corresponding to an element c _{x, 1st} whose result is z as a successful bidder;
Quality decoding procedure for decoding the encrypted quality Enc (qi) that corresponds to the seller i _1st determined in the successful bidder determination procedure stored in the declared information storage means to the computer,
Using the quality q _1st decoded in the quality decoding procedure and the function value b _2nd obtained in the next price calculation procedure, the seller i _1st is rewarded with {V (q _1st ) −b _2nd }. Reward calculation procedure obtained by calculation,
With publish seller i _1st determined in the successful bidder determination procedure in the computer as a successful bidder, a bid information published procedures to publish compensation determined in the compensation arithmetic procedure as a reward successful bidder,
An electronic procurement bidding program characterized in that

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