JP3619401B2 - Electronic bidding method, recording medium recording electronic bidding method, and electronic bidding apparatus - Google Patents

Description

を計算する。
【０００７】
（例えば、入札者Ｂ_ｉは、６０万円，・・・，１００万円では落札を希望せず、５０万円で希望する場合には、｛ω_１（１００万円），・・・，ω_ｖ−１（６０万円） ，ω_ｖｉ（５０万円） ｝に対する｛ｂ_ｉ１，・・・ｂ_{ｉ，ｖｉ−１，}ｂ_ｉ，ｖｉ｝は｛ｎｏ，・・・，ｎｏ，ｙｅｓ｝となる。）
（ステップ１３０）
入札値ｂ_ｉ，ｊに対するコミットメント
Ｌ_ｉ，ｊ＝Ｈ（ｂ_ｉ，ｊ，Ｌ_{ｉ，ｊ＋１}）（１≦ｊ≦ｖｉ）
を計算する。
【０００８】
（上記の計算は、｛０，１｝^ｔからランダムに選んだＬ_{ｉ，ｖｉ＋１}を初期値として、Ｌ_ｉ，ｖｉ＝Ｈ（ｂ_{ｉ，ｖｉ，}Ｌ_{ｉ，ｖｉ＋１}），・・・，Ｌ_ｉ，２＝Ｈ（ｂ_ｉ，２，Ｌ_ｉ，３），Ｌ_ｉ，１＝Ｈ（ｂ_ｉ，１，Ｌ_ｉ，２）により行う。）
（ステップ１４０）
ｂ_ｉ，１に対するコミットメントＬ_ｉ，１に対して、署名σ_ｉ＝Ｓｉｇ_Ｂｉ（Ｌ_ｉ，１）を計算する。
（この署名により入札は確かに入札者Ｂ_ｉが行ったものであることがわかる。）
（ステップ１５０）
ｂ_ｉ，１に対するコミットメントＬ_ｉ，１とその署名σ_ｉの組（Ｌ_ｉ，１、σ_ｉ ）を入札として、開札者Ａに送信する。
［開札手順］
開札者Ａは、図４に示す開札手順（２１０−２５０）により開札を行い、全入札者Ｂ_{ｉ（ｉ＝１，２，・・・，ｎ）}に入札値｛ｂ_１，１，ｂ_１，２，・・・_，ｂ_１，ｖｉ｝（入札者Ｂ_１），・・・｛ｂ_ｉ，１，ｂ_ｉ，２，・・・_，ｂ_ｉ，ｖｉ｝（入札者Ｂ_ｉ），・・・，｛ｂ_ｎ，１，ｂ_ｎ，２，・・・_，ｂ_ｎ，ｖｉ｝（入札者Ｂ_ｎ）〕を順に送信させて開札手順（２１０−２５０）により開札を行う。
（ステップ２１０）
入札者Ｂ_ｉから入札（Ｌ_ｉ，１，σ_ｉ ）を受信し、全入札者Ｂ_{ｉ（ｉ＝１，２，・・・，ｎ）}からの入札｛Ｌ_ｉ，１，σ_ｉ｝_{（ｉ＝１，２，・・・，ｎ）}が揃ったら、署名σ_ｉの正当性を検証し、全入札｛（Ｌ_ｉ，１，σ_ｉ）｝_{（ｉ＝１，２，・・・，ｎ）}を公開する。（例えば、｛（Ｌ_１，１，σ_１），・・・，（Ｌ_ｎ，１，σ_ｎ）｝を表示装置に表示して公開する。（この表示からは具体的な入札価格は知ることはできない。ただし、その後、入札価格等が改竄されれば｛（Ｌ_１，１，σ_１），・・・，（Ｌ_ｎ，１，σ_ｎ）｝が変わり、改竄されたことがわかる。）
（ステップ２２０）
ｊ＝１（すなわち、入札価格ω_１に対する全入札者Ｂ_{ｉ（ｉ＝１，２，・・・，ｎ）}の入札値｛ｂ_１，１，ｂ_２，１，・・・，ｂ_ｎ，１｝、ｊ＝２（すなわち、入札価格ω_２に対する全入札者（Ｂ_１，・・・，Ｂ_ｉ，・・・，Ｂ_ｎ）の入札値｛ｂ_１，２，ｂ_２，２，・・・，ｂ_ｎ，２｝、・・・を順に公開すると共に、ｊ＝１，２，・・・毎に以下のステップ （２３０−２５０）を行う。
（ステップ２３０）
入札者Ｂ_ｉから入札値（ｂ_ｉ，ｊ，Ｌ_{ｉ，ｊ＋１}）を受信し、全入札値｛（ｂ_ｉ，ｊ，Ｌ_{ｉ，ｊ＋１}）｝_{（ｉ＝１，２，・・・ｎ）}が揃ったら、コミットメントの正当性
Ｌ_ｉ，ｊ＝Ｈ（ｂ_ｉ，ｊ、Ｌ_{ｉ，ｊ＋１}）
を検証し、全入札値｛（ｂ_ｉ，ｊ、Ｌ_{ｉ，ｊ＋１}）｝_{（ｉ＝１，２，・・・，ｎ）}を公開する。
（ステップ２４０）
全てのｉに対して入札値ｂ_ｉ，ｊ＝ｎｏなら、ｊ＝ｊ＋１として（ステップ２３０）へ戻る。
（ステップ２５０）
あるｉに対して入札値ｂ_ｉ，ｊ＝ｙｅｓなら、ｖ＝ｊとして、Ｂ_ｉを落札者、ωｖを落札価格として公開する。
【０００９】
実施例２
図５は、本発明の電子入札装置のブロック図を示す。
電子入札装置１は、入札装置２と開札装置３から構成される。
入札装置１は、入札価格選択手段４，入札値計算手段５、コミットメント計算手段６、署名計算手段７及び一方向性関数記憶手段８とから構成される。
【００１０】
入札者Ｂ_{ｉ（ｉ＝１，２，・・・，ｎ）}は、公開されている入札価格表ω_{ｊ（ｊ＝１，２，・・・，ｖ，・・・，ｘ）}９を参照して入札価格選択手段４により入札価格ω_ｖｉを選択する。入札値計算手段５は、入札価格ω_ｖｉに対する入札価格ω_ｖｉに対して入札値ｂ_ｉ，１＝ｂ_ｉ，２＝・・・＝ｂ_{ｉ，ｖｉ−１}＝ｎｏ（落札しない）、ｂ_ｉ，ｖｉ＝ｙｅｓ（落札する）を計算する。コミットメント計算手段６は、一方向性関数Ｈの連鎖を用いて入札値ｂ_ｉ，ｊ に対するコミットメントＬ_ｉ，ｊ＝Ｈ（ｂ_ｉ，ｊ、Ｌ_{ｉ，ｊ＋１}）を計算する。署名計算手段７は、コミットメントＬ_ｉ，１に対しての署名σ_ｉ を計算する。そして、入札装置２は、入札（Ｌ_ｉ，１，σ_ｉ）を開札装置へ送信し、開札装置が署名σ_ｉが正当であることを検証すると共に、全入札を公開し、さらに、入札装置は、入札値（ｂ_ｉ，ｊ，Ｌ_{ｉ，ｊ＋１}）を開札装置へ送信し、開札装置がコミットメントＬ_ｉ，ｊ の正当性を検証し、この入札値の公開を確認したら、順次、入札値（ｂ_{ｉ，ｊ＋１}，Ｌ_{ｉ，ｊ＋２}）、（ｂ_{ｉ，ｊ＋２}，Ｌ_{ｉ，ｊ＋３}）、・・・を送信する。
【００１１】
開札装置３は、署名検証手段１０−１、全入札公開手段１０−２、コミットメント検証手段１１−１、全入札値公開手段１１−２、落札計算手段１２、落札者・落札価格公開手段１３及び一方向性関数記憶手段８とから構成される。
署名検証手段１０−１と全入札公開手段１０−２は、入札（Ｌ_ｉ，１，σ_ｉ）を受信して、署名σ_ｉの正当性を検証すると共に、全入札｛（Ｌ_ｉ，１，σ_ｉ）｝_{（ｉ＝１，２，・・・，ｎ）}を公開する。コミットメント検証手段１１−１と全入札値公開手段１１−２は、入札値（ｂ_ｉ，ｊ，Ｌ_{ｉ，ｊ＋１}）を受信し、一方向性関数Ｈを用いてコミットメントＬ_ｉ，ｊの正当性を検証すると共に、全入札値｛（ｂ_ｉ，ｊ，Ｌ_{ｉ，ｊ＋１}）｝_{（ｉ＝１，２，・・・，ｎ）} を公開する。また、落札計算手段１２は、入札値ｂ_ｉ，ｊを受信し、全てのｉに対して入札値ｂ_ｉ，ｊ＝ｎｏならば、ｊ＝ｊ＋１としてコミットメント検証手段１１−１、全入札値公開手段１１−２に送信し、あるｉに対して入札値ｂ_ｉ，ｊ＝ｙｅｓならば、落札と判断して落札者・落札価格公開手段１３に送信し、落札者・落札価格を公開する。
［例外処理］
入札値（ｂ_ｉ，ｊ，Ｌ_{ｉ，ｊ＋１}）を公開しない入札者Ｂ_ｉがいる場合、その入札者Ｂ_ｉを除いて、再度入札をやり直す。（現実には、公開しない入札者Ｂ_ｉに対しては、さらに預かり金没収などの罰則を設けて対処することとなる。）
【００１２】
【発明の効果】
本発明で提案する電子入札方法および装置は、一方向性関数の連鎖によるコミットメントを用いて構成されているためＳＨＡ−１などの実用的な一方向性関数を用いることにより、否認不可署名によるコミットメントを用いていた従来方式よりも効率的な電子入札方法及び装置を実現している。
【００１３】
さらに、電子入札方法及び装置として必要な次のような性質を備えている。
［正確性］
順に入札を開示していくので、最小のｖに対応するω_ｖで入札した入札者が落札する。
［検証可能性］
入札｛ｂ_ｉ，１，ｂ_ｉ，２，・・・_，ｂ_ｉ，ｖ｝とコミットメント｛Ｌ_ｉ，１，Ｌ_ｉ，２，・・・，Ｌ_{ｉ，ｖ＋１}｝は公開されているので、だれでも改竄の検証をすることができる。
［公平性］
開札以前に公開されているのはコミットメントＬ_ｉ，１のみなので、開札までは他の入札者の入札価格はわからない。
［価格秘匿性］
落札者が出たところで開札は終了し、落札者が出てきた以降の入札｛ｂ_{ｉ，ｖ＋１}，ｂ_{ｉ，ｖ＋２}，・・・，ｂ_ｉ，ｖｉ｝は公開されないので、落札価格以外の入札価格は秘匿されている。
［否認不可性］
コミットメントＬ_ｉ，１には入札者の署名σ_ｉ＝Ｓｉｇ_Ｂｉ（Ｌ_ｉ，１）が付いているので否認できない。
［不正者特定可能性］
コミットメントＬ_ｉ，ｊ が公開されているので入札ｂ_ｉ，ｊを偽った者は特定できる。また、一方向性関数Ｈの一方向性により、コミットメントＬ_ｉ，ｊ を後から改竄することはできない。
【図面の簡単な説明】
【図１】本発明の全体構成を示す図。
【図２】本発明の全体的な手順を示す図。
【図３】入札者Ｂ_ｉ の入札手順のブロック図。
【図４】開札者Ａの開札手順を示すブロック図。
【図５】本発明の電子入札装置のブロック図。
【符号の説明】
１ 電子入札装置
２ 入札装置
３ 開札装置
４ 入札価格選択手段
５ 入札値計算手段
６ コミットメント計算手段
７ 署名計算手段
８ 一方向性関数記憶手段
９ 入札価格表
１０−１ 署名検証手段
１０−２ 全入札公開手段
１１−１ コミットメント検証手段
１１−２ 全入札値公開手段
１２ 落札計算手段
１３ 落札者・落札価格公開手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an application technology of information security technology, and an electronic bidding apparatus in which a plurality of bidders distributed on a communication network such as the Internet make a bid using electronic communication, and The present invention relates to an electronic bidding method and a recording medium recording the electronic bidding method.
[0002]
[Prior art]
As a typical example of the conventional system, there is an electronic bidding system (S. Miyazaki, K. Sakurai, a possible electronic bidding system using a public bulletin board, SCIS '99 41-46 (1999)) by Miyazaki and Sakurai.
[0003]
[Problems to be solved by the invention]
In the conventional method, a commitment based on a non-repudiation signature (a signature method that can prove that a bidder is not bidding at a certain price) was used. In addition, there is a problem that efficiency is not good because communication is required.
[0004]
[Means for Solving the Problems]
Since the electronic bidding apparatus and method proposed by the present invention is configured using a commitment based on a chain of one-way functions, a practical one-way function such as SHA-1 is used as the one-way function. Thus, a more efficient bidding method than the conventional method is realized.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In the following, an embodiment of the present invention will be described.
FIG. 1 is a diagram showing the overall configuration of the present invention. Bidder _{B 1, B 2, ···,} B n (100) are coupled via a communication channel (300) and the tender opening's A (200).
Example 1
As shown in FIG. 2, bidder A first performs [pre-processing], and then each bidder B _{i (i = 1,..., N)} bids according to [bid procedure] (110-150). Finally, the bidder A performs bid opening according to [bid opening procedure] (210-250).
[0006]
FIG. 3 shows a block diagram of a bid procedure of the bidder B _i (100).
FIG. 4 shows a block diagram of the bid opening procedure of bid opener A (200).
[Preprocessing]
Bidder A has a bid price list {ω ₁ ,..., Ω _v−1 , ω _v ,..., Ω _x } (for example, {1 million yen,. , 500,000 yen,..., 100,000 yen}, that is, the bid opener presents a price range of 1 million yen to 100,000 yen and a specific bid price.) And a one-way function H: {0, 1} ^s × {0, 1} ^t → {0, 1} ^t
(Where {0,1} ^s is the entire set of s-bit bit strings consisting of a set of {0,1}, and {0,1} ^t is the total set of t-bit bit strings consisting of a set of {0,1}. Decide and release it. In practice, a practical one-way function such as SHA-1 is used as the one-way function. Also, “no” (message not to make a successful bid) and “yes” (message to make a successful bid) ∈ {0, 1} ^s are disclosed.
[Bid procedure]
The bidder B _i bids according to the bidding procedure (110-150) shown in FIG.
(Step 110)
The bidder B _i selects the bid price ω _vi from the bid price list {ω ₁ ,..., Ω _v−1 , ω _v ,..., Ω _x } (for example, 500,000 yen).
(Step 120)
Bid price for bid price ω _vi

Calculate
[0007]
(For example, the bidder B _i does not wish to make a successful bid at 600,000 yen,..., 1 million yen, and when he / she wishes to pay 500,000 yen, {ω ₁ (1 million yen),. {b _i1 ,... bi _{, vi −1,} bi _{, vi} } for ω _v−1 (600,000 yen), ω _vi (500,000 yen)} are {no,..., no, yes} Will be.)
(Step 130)
Commitment L _{i, j} = H (b _{i, j,} L _{i, j + 1} ) (1 ≦ j ≦ vi) for bid value b _{i, j}
Calculate
[0008]
(In the above calculation, L _{i, vi + 1} randomly selected from {0,1} ^t is used as an initial value, L _{i, vi} = H (b _{i, vi,} L _{i, vi + 1} ),..., L _{i , 2} = H (b _{i, 2,} L _{i, 3} ), L _{i, 1} = H (b _{i, 1,} L _{i, 2} )
(Step 140)
For the commitment L _{i, 1} for b _{i, 1} , compute the signature σ _i = Sig _Bi (L _{i, 1} ).
(This signed by the bid it is understood that certainly bidder B _i did.)
(Step 150)
A set (L _{i, 1} , σ _i ) of the commitment L _{i, 1} and its signature σ _i for b _{i, 1} is sent as a bid to the bidder A.
[Bid opening procedure]
The bid opener A performs bid opening by the bid opening procedure (210-250) shown in FIG. 4, and bids {b _1,1 , b _{1 to} all bidders Bi _{(i = 1, 2,..., N). , 2,} ... _, B _{1, vi} } (bidder B ₁ ),... {Bi _{, 1} , bi _{, 2,} ... _, Bi _{, vi} } (bidder B _i ) _,. .., {B _{n, 1} , b _{n, 2,} ... _, B _{n, vi} } (bidder B _n )] are sequentially transmitted, and a bid opening procedure (210-250) is performed.
(Step 210)
Bid bidder _{B i (L i, 1,} σ i) receives, all bidders _{B i (i = 1,2, ···} , n) bids from _{{L i, 1, σ i} } ( _{When i = 1, 2,..., n),} the validity of the signature σ _i is verified, and all bids {(L _{i, 1,} σ _i )} _{(i = 1, 2,. n)} to the public. (For example, {(L _1,1, σ ₁ ),..., (L _{n, 1,} σ _n )} is displayed on a display device and is disclosed (a specific bid price is known from this display). However, if the bid price is falsified after that, {(L _1,1, σ ₁ ), ..., (L _{n, 1,} σ _n )} will change and it will be understood that it has been falsified. .)
(Step 220)
j = 1 (that is, bid values {b _1,1 , b _2,1 ,..., b _n, of all bidders _{Bi (i = 1, 2,..., n)} for the bid price ω _{1 ) . 1} }, j = 2 (that is, bid values {b ₁ , ₂ , b ₂ , ₂ ,... Of all bidders (B ₁ ,..., B _i ,..., B _n ) for the bid price ω ₂ ). .., B _{n, 2} },... Are disclosed in order, and the following steps (230-250) are performed every j = 1, 2,.
(Step 230)
Bid value (b _{i, j} , L _{i, j + 1} ) is received from bidder B _i , and all bid values {(b _{i, j} , L _{i, j + 1} )} _{(i = 1, 2,... N)} If we have, the legitimacy of commitment L _{i, j} = H (b _{i, j} , L _{i, j + 1} )
, And disclose all bid values {(b _{i, j} , L _{i, j + 1} )} _{(i = 1, 2,..., N)} .
(Step 240)
If the bid value b _{i, j} = no for all i, then j = j + 1 is set (step 230).
(Step 250)
If the bid value b _{i, j} = yes for a certain i, then v = j, and B _i is released as the winning bidder and ωv as the winning bid price.
[0009]
Example 2
FIG. 5 shows a block diagram of the electronic bidding apparatus of the present invention.
The electronic bidding apparatus 1 includes a bidding apparatus 2 and a bid opening apparatus 3.
The bidding apparatus 1 includes a bid price selection unit 4, a bid price calculation unit 5, a commitment calculation unit 6, a signature calculation unit 7, and a one-way function storage unit 8.
[0010]
Bidders B _{i (i = 1, 2,..., N)} refer to the published bid price list ω _{j (j = 1, 2,..., V,..., X)} 9 Then, the bid price ω _vi is selected by the bid price selection means 4. The bid price calculation means 5 uses the bid price b _{i, 1} = b _{i, 2} =... = B _{i, vi-1} = no (no successful bid), b _i for the bid price ω _vi for the bid price ω _vi . _{, Vi} = yes (successful bid) is calculated. The commitment calculation means 6 calculates a commitment L _{i, j} = H (b _{i, j} , L _{i, j + 1} ) for the bid value b _{i, j} using a chain of one-way functions H. The signature calculation means 7 calculates a signature σ _i for the commitment L _{i, 1} . Then, the bidding device 2 transmits a bid (L _{i, 1} , σ _i ) to the bid opening device, the bid opening device verifies that the signature σ _i is valid, and discloses all bids. Transmits the bid value (b _{i, j} , L _{i, j + 1} ) to the bid opening device, and the bid opening device verifies the validity of the commitment L _{i, j} and confirms the release of the bid value. (B _{i, j + 1} , L _{i, j + 2} ), (b _{i, j + 2} , L _{i, j + 3} ),... Are transmitted.
[0011]
The bid opening device 3 includes a signature verification unit 10-1, an all bid disclosure unit 10-2, a commitment verification unit 11-1, an all bid price disclosure unit 11-2, a successful bid calculation unit 12, a successful bidder / successful bid price disclosure unit 13, and And a one-way function storage means 8.
The signature verification unit 10-1 and all bid disclosure unit 10-2 receive the bid (L _{i, 1} , σ _i ), verify the validity of the signature σ _i , and verify all bids {(L _{i, 1} , Σ _i )} _{(i = 1, 2,..., N)} . The commitment verification unit 11-1 and all bid price disclosure unit 11-2 receive the bid value (b _{i, j} , L _{i, j + 1} ) and use the one-way function H to verify the validity of the commitment L _{i, j} . And the total bid price {(b _{i, j} , L _{i, j + 1} )} _{(i = 1, 2,..., N)} is disclosed. Also, the successful bid calculation means 12 receives the bid values b _{i, j} and if the bid values b _{i, j} = no for all i, j = j + 1 is set as the commitment verification means 11-1, and all bid values are disclosed. If the bid value b _{i, j} = yes with respect to a certain i, it is judged as a successful bid and sent to the winning bidder / successful bid price disclosing means 13 to disclose the winning bidder / successful bid price.
[Exception handling]
When there is a bidder B _i who does not disclose the bid value (b _{i, j} , L _{i, j + 1} ), the bidder B _i is excluded and the bid is performed again. (In reality, bidders _Bi that are not disclosed will be dealt with by providing penalties such as confiscation of deposits.)
[0012]
【The invention's effect】
Since the electronic bidding method and apparatus proposed in the present invention is configured using a commitment based on a chain of one-way functions, a commitment based on a non-repudiation signature is obtained by using a practical one-way function such as SHA-1. E-bidding method and apparatus that are more efficient than the conventional method using the.
[0013]
Furthermore, it has the following properties required as an electronic bidding method and apparatus.
[Accuracy]
Since going to disclose the bid in order, it bids the bidders to bid at ω _v corresponding to the minimum of v.
[Verification possibility]
Since the bids {b _{i, 1} , b _{i, 2,} ... _, B _{i, v} } and commitments {L _{i, 1} , L _{i, 2} ,..., L _{i, v + 1} } Anyone can verify tampering.
[fairness]
Since only the commitment Li _{, 1} is disclosed before the bid opening, the bid price of other bidders is not known until the bid opening.
[Price confidentiality]
The bid opening ends when the winning bidder comes out, and the bids {bi _{, v + 1} , bi _{, v + 2} ,..., Bi _{, vi} } after the winning bidder comes out are not disclosed. The price is kept secret.
[Non-repudiation]
Since the commitment L _{i, 1} has the bidder signature σ _i = Sig _Bi (L _{i, 1} ) _, it cannot be denied.
[Possibility to identify unauthorized persons]
Since the commitment L _{i, j} is open to the public, it is possible to specify a person who has falsely advertised the bid b _{i, j} . Further, due to the unidirectionality of the unidirectional function H, the commitment L _{i, j} cannot be tampered later.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of the present invention.
FIG. 2 is a diagram showing an overall procedure of the present invention.
FIG. 3 is a block diagram of the tender procedure bidders B _i.
FIG. 4 is a block diagram showing a bid opening procedure of a bidder A.
FIG. 5 is a block diagram of an electronic bidding apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic bid apparatus 2 Bid apparatus 3 Bid opening apparatus 4 Bid price selection means 5 Bid price calculation means 6 Commitment calculation means 7 Signature calculation means 8 Unidirectional function storage means 9 Bid price list 10-1 Signature verification means 10-2 All bids Disclosure means 11-1 Commitment verification means 11-2 All bid price disclosure means 12 Successful bid calculation means 13 Successful bidder / successful bid price disclosure means

Claims (8)

When bidding by a plurality of bidders Bi _{(i = 1, 2, ... , N)} on the bidder side against the bidder A on the bidder side, a bid opening device provided on the bid opening side and a bid device provided on the bid side are provided. In an electronic bidding method that connects via a network and places a bid,
The bid device obtains the bid price list ω _{j (j = 1, 2, ... , V, ... , X)} and the one-way function H that are opened by the bidder A,
Bid value b _i for the bidding price ω _vi bidder _{B i, 1 = b i,} 2 = ··· = b i, vi-1 = no ( not _bid), b _i, to _vi = yes (successful bid ) For calculating 2),
Commitment L _{i, j} = H (b _{i, j} , L _{i, j + 1} ) by a chain of one-way functions H is calculated for the bid price, and a set of commitment L _{i, 1} and its signature σ _i ( L _{i, 1} , σ _i ) as a bid to be sent to the bid opening device;
The bid opening device receives the bid (L _{i, 1} , σ _i ) transmitted,
Step 5 for verifying that the signature σ _i is valid when all the bidders have bids from the bidders, and publishing bids from all bidders bidders;
Step 6 with j = 1,
When the bid value (b _{i, j} , L _{i, j + 1} ) is received from the bidding device and the bid values of all bidders are obtained _, the validity L _{i, j} = H (b _{i, j j} , L _{i, j + 1} ) and publishing all bid values {(b _{i, j} , L _{i, j + 1} )};
If bid value b _{i, j} = no for all _{i, then} step 8 with j = j + 1 and returning to step 7;
Bid b _i for some _{i, j} = yes If the B _i successful bidder, electronic bidding method characterized by having a step 9 to publish and determines the omega _j as the winning bid. The bid apparatus obtains the bid price table ω _{j (j = 1, 2, ... , V, ... , X)} and the one-way function H published by the bidder A , and
Bid value b _{i, 1} = b _{i, 2} = ... = b for bid price ω _vi selected from bid price table ω _j by bidder B _{i (i = 1, 2, ... , N)} Procedure 2 for calculating _{i, vi-1} = no (no successful bid), b _{i, vi} = yes (successful bid),
Commitment L _{i, j} = H (b _{i, j} , L _{i, j + 1} ) is calculated for the bid value b _{i, j} by a chain of one-way functions H, and commitment L _{i, 1} and its signature σ Step 3 for transmitting a set of _i ( L _{i, 1} , σ _i ) to the bid opening device as a bid, and when the bid is released, the bid value (b _{i, 1} L _{i, 2} ) is transmitted to the bid opening device, Each time the bid price (b _{i, j ,} L _{i, j + 1} ) is released, the bid price ( b _{i, j + 1} , L _{i, j + 2} ), ( b _{i, j + 2} , L _{i, j +)} bid, characterized in that it comprises ₃₎ and step 4 to send ... to the tender opening device. A computer-readable recording medium recording a bidding program for causing a computer constituting the bidding apparatus to execute each procedure of the bidding method according to claim 2 . The bid opening device receives the bid ( L _{i, 1} , σ _i ) transmitted from the bid device , and i = 1, 2,... N, the bid value b _{i, 1} is a bid price list. Bidding value for ω ₁ when ω _{j (j = 1, 2, ... , v, ... , x)} (yes: successful bid, no: no successful bid), L _{i, 1} = H (b _{i, 1} , L _{i, 2} ) is equal to L _{i , vi + 1} if the bid value (b _i1 ,..., b _{i , vi−1} , b _{i , vi} ) is (no , ... , no , yes) as initial value, the chain _{L i} one-way function H to bid _{b i, j, j = H} (b i, j, L i, j + 1) calculated bid b _{i, 1} commitment by, sigma _i Is the signature of commitment L _{i, 1}
Step 2 for verifying that the signature σ _i is valid when all the bidders have bids from the bid devices, and publishing bids from all bidders' bid devices;
Step 3 with j = 1,
When the bid value (b _{i, j} , L _{i, j + 1} ) is received from the bidding device and the bid values of all bidders are obtained _, the validity L _{i, j} = H (b _{i, j j} , L _{i, j + 1} ), and publishing all bid values {(b _{i, j} , L _{i, j + 1} )},
If bid value b _{i, j} = no for all _i, then go back to step 4 with j = j + 1 and step 5;
Bid opening method characterized by having a step 6 to expose and determines bid b _i for some _i, a _j = yes When bidder B _i successful bidder, the omega _j as the winning bid. A computer-readable recording medium recording a bid opening program for causing a computer constituting the bid opening apparatus to execute each procedure of the bid opening method according to claim 4 . The electronic bidding device consists of a bidding device and a bid opening device connected via a network.
The bidding device comprises a bid price selection means, a bid price calculation means, a commitment calculation means, a signature calculation means, and a one-way function storage means,
Bid selection means, bidder _{B i (i = 1,2, ···} , n) the bid price list ω _j bid from the _{(j = 1,2, ···, v} , ···, x) is a means for selecting the price ω _vi, bid value calculation means, bid value _{b i, 1 = b i,} 2 = ··· = b i for the selected bidding price ω _{vi, vi-1} = no (not awarded), b _i, to calculate the _vi = yes (to bid), the commitment calculating means, a one-way function bid using a chain of H b _i, commitment to _{j L i, j = H (} b _{i, j} , L _{i, j + 1} ), the signature calculation means calculates the signature σ _i for the commitment L _{i, 1} , and the bidding device determines the bid (L _{i, 1} , σ _i ) sends to the bid opening device, the total bid is published, and sends the bid values _{(b i, 1 L i,} 2) to the bid opening device, bid value _{(b i, j, L i} , j + 1) is When published , bid values (b _{i, j + 1} , L _{i, j + 2} ), (b _{i, j + 2} , L _{i, j + 3} ), etc. are sent in sequence,
The bid opening device is composed of signature verification means, all bid release means, commitment verification means, all bid price release means, successful bid calculation means, successful bidder / successful bid price release means, and one-way function storage means,
The signature verification means and all bid release means receive the bid (L _{i, 1} , σ _i ), verify the validity of the signature σ _i , release all bids, and release the commitment verification means and all bid values The means receives the bid value (b _{i, j} , L _{i, j + 1} ), and receives the validity L _{i, j} = H (b _{i, j} , L _{i, j + 1} ) of the commitment L _{i, j.} In addition to verifying, all bid values {(b _{i, j} , L _{i, j + 1} )} are made public, and the winning bid calculation means is _j = if bid values b _{i, j} = no for all i. j + 1 is sent to the commitment verification means and all bid price disclosure means. If bid price b _{i, j} = yes for a certain i, it is judged as a successful bid and sent to the winning bidder / successful bid price disclosure means. The e-bidding apparatus is characterized in that the bidder / successful bid price disclosing means discloses the successful bidder and the successful bid price. A bid price selection means, a bid price calculation means, a commitment calculation means, a signature calculation means, and a one-way function storage means,
Bid selection means, bidder _{B i (i = 1,2, ···} , n) the bid price list ω _j bid from the _{(j = 1,2, ···, v} , ···, x) is a means for selecting the price ω _vi, bid value calculation means, bid value for the bid price _{ω vi b i, 1 = b} i, 2 = ··· = b i, vi-1 = no ( not bid ), b _i, to calculate the _vi = yes (to bid), the commitment calculating means, the bid value b _i using a chain of one-way function _H, commitment to _{j L i, j = H (} b i, j , L _{i, j + 1} ), the signature calculation means calculates the signature σ _i for the commitment L _{i, 1} and sends the bid ( L _{i, 1} , σ _i ) to the bid opening device, When the bid is released, the bid price (b _{i, 1} L _{i, 2} ) is transmitted to the bid opening device, and when the bid price (b _{i, j} L _{i, j + 1} ) is released , the bid price ( B _{i, j + 1} , L _{i, j + 2} ), (b _{i, j + 2} , L _{i, j + 3} ),... Signature verification means , all bid disclosure means, commitment verification means, all bid price disclosure means, successful bid calculation means, successful bidder / successful bid price disclosure means, one-way function storage means and bid price table ω _{j (j = 1, 2, ... , v, ... , x)}
The signature verification means and all the bid disclosing means receive the bid (L _{i, 1} , σ _i ) of the bidder B _{i (i = 1, 2, ... , N)} and verify the validity of the signature σ _i. In addition to verifying, all bids {(L _{i, 1} , σ _i )} are disclosed, and the commitment verification means and all bid price disclosure means receive the bid values (b _{i, j} , L _{i, j + 1} ). , The validity L _{i, j} = H (b _{i, j} , L _{i, j + 1} ) of the commitment L _{i, j} is verified, and all bid values {(b _{i, j} , L _{i, j + 1} ) }, And if the bid price b _{i, j} = no for all i, the bid calculation means sends j = j + 1 to the commitment verification means and all bid price publication means, If the bidding value b _{i, j} = yes, the winning bidder and the winning bid price disclosing means are judged and sent to the winning bidder and the winning bid price disclosing means, and the winning bidder and winning bid price disclosing means disclose the winning bidder and winning bid price. However, the bid price b _{i, 1} is the bid price for ω ₁ ( yes : make a successful bid, no : make a successful bid _Have), L _{i, 1} Is the bid price b _{i, 1} Commitment, σ _i Is the signature of commitment L _{i, 1} .

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