JP3798160B2 - Bidding system, confidential information holding system, supply side apparatus and procurement side apparatus in bidding system, and secret information holding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a technique for securely holding secret information used among a plurality of parties, and an electronic bidding system to which this technique is applied.
[0002]
[Prior art]
An information processing device (hereinafter referred to as “procurement-side device”) operated by an organizer who sponsors a bid and an information processing device (hereinafter referred to as “supply-side device”) operated by a plurality of participants participating in the bid. For example, an electronic bidding system that performs electronic bidding by connecting through the Internet is known. In this type of electronic bidding system, it is a big problem to hold a bid document (bid participation application form) which is secret information without being falsified until the bid opening time is reached. Therefore, conventionally, when the bidding procedure is digitized, two methods of “time key method” and “common key method” are adopted, thereby trying to prevent falsification within a certain time.
[0003]
The “time key method” is a method in which the management of a public key for encrypting information and a secret key corresponding thereto is entrusted to a trusted third party (hereinafter referred to as “TTP”).
That is, a public key and a corresponding private key are generated by TTP, and TTP announces the public key at the request from the procurement side device. The procurement side device passes this public key to the supply side device that makes the bid application. The supply-side device encrypts the bid document with the passed public key, and submits the encrypted bid document (hereinafter referred to as “encrypted bid document”) to the procurement-side device. TTP also manages the bid opening time, and when that time is reached, the secret key is issued to the procurement side device. As a result, the procurement side device decrypts the encrypted tender document with the secret key and provides it for bid opening. By using this time key method, no one can know the contents of the bid information until the bid opening time is reached. In addition, it becomes possible to prevent falsification after the bid opening of the procurement side device due to the prior disclosure of the hash value of the bid document.
[0004]
On the other hand, the “common key distribution method” is a method that uses a unique common key for each supply-side device. That is, the supply-side device holds a common key, and the encrypted bid form encrypted with the common key is submitted to the procurement-side device. When the bid opening time comes, the supply side device autonomously passes its own common key to the procurement side device. Using this common key, the procurement-side apparatus decrypts the encrypted tender and opens the bid. By using this common key distribution method, the procurement side apparatus cannot know the contents of the bid information until the bid opening time is reached. In addition, it becomes possible to prevent falsification after the bid opening of the procurement side device due to the prior disclosure of the hash value of the bid document.
[0005]
[Problems to be solved by the invention]
However, each method described above has the following problems.
First, in the time key method, the existence of a TTP for managing keys is indispensable. In addition, when there is no TTP, the bid opening times cannot be aligned.
In addition, in the common key distribution method, it is difficult to guarantee the same-time bid opening, and in order to realize this, it is necessary to transmit each common key to the procurement side device to the plurality of supply side devices at the same time. Ingenuity is required in the operation form such as requesting. Further, since the supply side device needs two transmission actions, that is, the transmission of the encrypted tender to the procurement side device and the transmission of the common key at the bid opening time, it takes time and labor.
[0006]
Therefore, an object of the present invention is to provide a secret information holding method capable of reliably preventing falsification of secret information without using a third party organization such as TTP.
Another object of the present invention is to provide a secret information holding system suitable for the implementation of the secret information holding method and an electronic bidding system to which this method is applied.
[0007]
[Means for Solving the Problems]
The secret information holding method of the present invention that solves the above-described problems includes a process of encrypting secret information using all of a plurality of encryption keys released at the same time, and the encrypted secret information as the encryption key. And a process of decrypting all corresponding decryption keys at the same time. Thereby, since the decryption cannot be performed unless a plurality of decryption keys are prepared at the same time, the security of the secret information can be ensured. The “simultaneous period” here does not necessarily have to be the same time, and if it is a fixed time, it corresponds to the same period.
[0008]
The secret information holding system of the present invention that solves the above-mentioned other problems includes means for encrypting secret information with encryption keys acquired from all of a predetermined number of devices each having a unique encryption key and a corresponding decryption key; And means for decrypting the encrypted secret information with a decryption key acquired from all of the predetermined number of devices, and the decryption is permitted only when the predetermined number of decryption keys exist at the same time. It is characterized by doing.
In order to secure the security of the secret information more firmly, the first means is configured to add a digital signature to the secret information before encryption, and the second means is set after the decryption. The validity of the digital signature is determined.
[0009]
This secret information holding system includes, for example, one of the following first and second information processing apparatuses.
The first information processing apparatus includes an encryption unit that encrypts secret information based on encryption keys acquired from all of a predetermined number of apparatuses each having a unique encryption key and a corresponding decryption key, and the predetermined information A decryption unit that decrypts the encrypted secret information based on decryption keys acquired from all of the devices, and the decryption is performed only when the predetermined number of decryption keys exist at the same time. It is characterized by permitting.
[0010]
The second information processing device is a device that has a unique encryption key and a corresponding decryption key, and encrypts secret information with encryption keys acquired from all of a predetermined number of devices including the device itself. Sending the encryption key of the own device to the means, and sending the decryption key of the own device to the decrypting means for decrypting the encrypted secret information with the decryption keys acquired from the predetermined number of devices The decryption is permitted only when the predetermined number of decryption keys exist at the same time.
[0011]
The electronic bidding system of the present invention that solves the above other problems includes a plurality of first devices participating in bidding, and a second device that opens bids based on bid information from the plurality of first devices,
Each of the first devices notifies the second device of a unique encryption key, encrypts bid information of the own device with the encryption keys of all the first devices including the own device acquired at the same time, and First means for sending the converted bid information and the decryption key corresponding to the encryption key to the second device;
The second device publishes the encryption keys of all the first devices at a predetermined time and simultaneously sends the encrypted bid information and the decryption key from all the first devices corresponding to the disclosure. It has a second means for obtaining, decrypting each encrypted bid information with all decryption keys and providing it to the bid opening. The second device is provided with a third means for presenting the principal information of the bid opening to the first device in real time as necessary.
[0012]
In the present invention, the key generation and the delivery thereof may be a public key method, a secret key method, or a common key method.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the secret information holding method of the present invention is applied to an electronic bidding system using the Internet will be described with reference to the drawings.
FIG. 1 is a configuration diagram of the electronic bidding system according to the present embodiment.
The electronic bidding system 1 includes a procurement side device 10 and a plurality of supply side devices 20.
[0014]
The procurement apparatus 10 supports an operating system (hereinafter referred to as “OS”) 11 and TCP / IP (Transmission Control Protocol / Internet Protocol), HTTP (Hyper Text Transfer Protocol), and SMTP (Simple Mail Transfer Protocol) as protocols thereof. The information processing apparatus has the functions of the mail client 12, the web (Web) server 13, and the mail server 14.
[0015]
For example, the mail client 12 receives mail from the supply-side device 20, and the web server 13 publishes information on its own web that can be browsed on the supply device side 20. The mail server 14 performs, for example, mail transmission to the supply side device 20. For mail transmission, for example, a known S / MIME (Security Services for MIME) system is used. As a result, the security of the transmission content can be ensured. Note that the names of the above functions 12 to 14 are given for convenience in order to describe the function contents in the present embodiment.
[0016]
The procurement-side apparatus 10 is also equipped with a dedicated application 15 for enabling an electronic bidding procedure using the OS 11 and the above functions 12 to 14.
The dedicated application 15 cooperates with the OS 11 to display various modules shown in FIG. 2, that is, a bid permission module 151, a mail transmission command module 152, a web release command module 153, a bid acceptance module 154, a decryption key storage module 155, a bid opening determination A module 156, a bid opening module 157, a decryption module 158, and a display module 159 are formed. In FIG. 2, reference numerals (1) to (16) indicate the flow of processing between the modules.
[0017]
The function content of each module 151-159 is as follows.
When the bid permission module 151 receives mail through the mail client 12 (symbol (1)), the bid permission module 151 transmits the bid participation permission mail and the encryption key to the mail transmission source, that is, the supply side device 20 through the mail transmission command module 152. Instructing disclosure (reference (2)). In addition, the web server 13 is instructed through the web publication command module 153 to indicate that the key has been released or that the deadline has passed (codes (3) and (4)). Until the deadline, the processes (1) to (3) are repeated.
[0018]
The bid accepting module 154 accepts the decryption key and the encrypted tender for each supply side device 20 through the mail client 12 (reference (6)) in response to the bid acceptance phase transition notification (reference (5)) from the bid permission module 151. ), The decryption key is transferred to the decryption key storage module 157 (symbol (7)). Further, the bid opening determination module 155 is inquired whether all supply-side devices 20 participating in the bid are prepared (reference (8)), and when notified that the supply is complete (reference (10)), A notice of transition to the bid opening phase is sent to the bid opening module 157 together with the encryption bid documents of all the supply side devices 20 (reference numeral (11)).
[0019]
The bid opening determination module 155 knows the number of the supply side devices 20 participating in the bid, and transmits a bid opening notification mail to all the supply side devices 20 through the mail transmission command module 152 and the mail server 14 (symbol (9 )). Also, the number of receipts from the bid acceptance module 154 (the number of decryption keys and the number of encrypted bid documents) is compared with the number of mail transmission destinations, and if they match, the notification is returned to the bid acceptance module 154 (reference (10)). ).
[0020]
The bid opening module 157 acquires the decryption keys of all the supply side devices 20 from the decryption key storage module 156 in response to the bid opening phase transition notification (codes (12) and (13)), and uses them for all the supply device side 20s. It is passed to the decryption module 158 together with the cipher bid (code (14)). When a decrypted bid document is received from the decryption module 158 (symbol (15)), it makes a successful bid and displays its essential information, such as the lowest price (excluding the company name) and the necessity of re-bidding. It is displayed on the web through the module 159 and the web server 13 (reference numeral (16)).
[0021]
Returning to FIG. 1, the supply-side device 20 is an information processing device having an OS 21 and functions of a mail client 22, a web browser 23, and a mail server 24 that support the aforementioned TCP / IP, HTTP, and SMTP as protocols. is there.
[0022]
For example, the mail client 22 receives mail from the procurement apparatus 10. The web browser 23 is for browsing information and obtaining information published on, for example, a SSL (Secure Socket Layer) compatible web. The mail server 24 performs, for example, mail transmission to the procurement apparatus 10. Mail transmission is performed using, for example, the S / MIME system. Note that these function names are also given for convenience in the present embodiment.
[0023]
The supply-side apparatus 20 is also equipped with a dedicated application 25 for enabling an electronic bidding procedure using each function 22 described above. The dedicated application 25 cooperates with the OS 21 to display various modules shown in FIG. 3, that is, a bid participation application module 251, a key pair creation module 252, a mail transmission command module 253, a key acquisition module 254, a bid document creation module 255, an encryption This is for forming the control module 256.
In FIG. 3, reference numerals (1) to (11) indicate the flow of processing between the modules.
[0024]
The function content of each module 251 to 259 is as follows.
The bid participation application module 251 receives a key pair for the participation case, that is, an encryption key, when information on the case subject to bidding (hereinafter referred to as “case information”) is confirmed through the web browser 23 (symbol (1)). A decryption key pair is received from the key pair creation module 253 (codes (2) and (3)). Then, the encryption key and the bid participation application form are transmitted to the procurement apparatus 10 through the mail transmission command module 252 and the mail server 24 (reference numeral (4)). When the participation permission is given, the key acquisition module 254 is notified of the transition to the key acquisition phase (symbol (5)).
[0025]
The key acquisition module 254 acquires the public encryption key through the web browser 23 (reference numeral (6)), and when the encryption keys of all the supply side devices 20 are acquired, the key acquisition module 255 receives a bid document. The creation phase transition is notified (symbol (7)). Also, all the obtained encryption keys are presented in response to a request from the encryption module 256 (reference numerals (9) and (10)).
[0026]
The bid book creation module 255 creates a bid book created upon receipt of notification of the transition to the bid book creation phase, and requests the encryption module 256 to encrypt it (reference (8)). When the encryption module 256 receives an encryption bid document encrypted with all the above encryption keys (symbol (11)), it is sent to the procurement apparatus 10 through the mail transmission command module 252 and the mail server 24. Transmit (symbol (12)).
[0027]
Next, the operation mode in the electronic bidding system 1 configured as described above will be specifically described with reference to FIG.
<Bid participation application phase>
First, the procurement-side apparatus 10 publishes project information on the web (T1). When the supply side device 20 knows the case information through the web browser 23 of its own device, the supply side device 20 creates a pair of an encryption key and a decryption key. These keys are specialized for each item information, and will not be used after bidding. Thereafter, the encryption key of the key pair is sent by e-mail to the procurement apparatus 10 by the S / MIME method (K1, K2). At the same time, an application form (electronic information) for bid participation is sent and waiting for permission to participate in the bid.
[0028]
The procurement apparatus 10 sends a notification of participation permission to the supply apparatus 20 by e-mail and publishes the encryption key of the supply apparatus 20 on the web through the web server 13 (T2). This process (K1 to T2) is repeated until the deadline for bid participation is reached. At this time, the procurement-side apparatus 10 publishes the bid participation status on the web in real time. As a result, each supply-side device 20 can know how much participation has been made for the item information. If the procurement side device 10 reaches the deadline for bid participation, the procurement side device 10 publishes the fact on the web (T3).
[0029]
<Bid reception phase>
When the supply-side device 20 permitted to participate knows the bid participation deadline through the web browser, the supply-side device 20 acquires the encryption keys of all the other competing supply-side devices 20 through the SSL-compatible web browser 23 (K3, K4).
In addition, a tender document in which the proposed price and the name of the user are described is created (K5), and the tender document is prepared in a predetermined order (for example, the encryption key for company A → the encryption key for company B → the encryption key for company C). Encrypt in (...) to create an encrypted bid. Thereafter, the encrypted bid form and its own decryption key are mailed to the procurement side apparatus 10 in E / MIME format (K6). These processes (K3 to K6) are executed in all the supply side devices 20.
[0030]
The procurement side device 10 publishes the bid acceptance status on the web in real time and stores the received decryption key of the supply side device 20 (T4). Further, it is determined whether or not the bid opening is possible, that is, whether or not the decryption key and the encrypted bid book are prepared from all the supply side devices 20 participating in the bid (T5). When the decryption keys are available, the fact that the billing phase is to be shifted is disclosed on the web.
[0031]
<Bid opening phase>
In the bid opening phase, a bid opening notice is transmitted from the procurement side apparatus 10 to each supply side apparatus 20 by e-mail. The procurement-side apparatus 10 also decrypts each encrypted tender with all the decryption keys in the reverse order of the encryption (the decryption key for company C → the decryption key for company B → the decryption key for company A) ( T6). At this time, the procurement side device 10 can visualize the proposed price and the like for the first time, and since the time becomes the bid opening time, the procurement side device 10 cannot set the bid opening time to an arbitrary time.
[0032]
After that, the information on the main part of the successful bid is published on the web, and in the case of a required subsequent procedure, for example, when a successful bid is made, if an e-mail is sent to the corresponding supply side device 20 or a bid is made again, that fact Web publication etc. are performed (T7).
[0033]
When the supply-side device 20 declines after submitting the encrypted tender, it is preferable to have the tender withdrawal (electronic information) and the decryption key submitted. In addition, when there are a large number of supply side devices 20 participating in the bidding, the supply side device 20 is arbitrarily divided into several groups, and the above-mentioned encryption and decryption are performed for each group. It is also possible to reduce processing.
[0034]
As described above, in the electronic bidding system 1 of the present embodiment, the electronic bidding procedure can be performed through the Internet L, so that it is not necessary for the participant to go to the procurement side. In addition, the contents of the bid information cannot be grasped unless all the keys are available, and the bid acceptance status and bid results are published on the web in real time, providing a strong sense of reality and transparency to the bid participants. You can appeal to.
[0035]
In addition, as in the conventional method, falsification of bid information can be reliably prevented without using TTP, and the bid opening times can be made uniform, so that fairness of bids can be maintained. Further, there is an advantage that transmission from each supply-side device 20 to the procurement-side device 10 is only required once.
[0036]
The above is an example of a system configuration when TTP is not used. From the viewpoint of effectively preventing falsification of bid information, particularly falsification after bid opening, TTP is different from management of encryption keys and decryption keys. It can be used in the form of That is, before the tender is encrypted by the supply-side device 20, a digital signature is added to each tender. In this case, the procurement apparatus 10 acquires the key from the TTP and confirms the validity of the digital signature.
[0037]
In this embodiment, an example in which the procurement apparatus 10 and the supply apparatus 20 are connected via the Internet L has been shown. However, an embodiment in which both apparatuses are connected via a wide area network other than the Internet or a local network is also possible. is there. Further, a key, a cryptographic bid, etc. may be delivered using a portable medium as a medium instead of a network. In this case, the mail means is not necessary, but a large view system that replaces the web will be required.
[0038]
In addition, since the present invention mainly focuses on the fact that the secret information can be decrypted only when the decryption keys corresponding to the plurality of encryption keys are all prepared at the same time, various application examples are possible in addition to the above embodiment. It is.
For example, it can be applied to a will system that uses secret information as a will. That is, after a digital signature is added to a will, it is encrypted in a predetermined order with encryption keys assigned to a plurality of heirs. Then, when all of the heir's decryption keys are prepared, the encrypted will is decrypted in the reverse procedure of the encryption, and the validity of the digital signature is further determined. As a result, falsification of the will is surely prevented.
[0039]
【The invention's effect】
As is clear from the above description, according to the present invention, the contents of the secret information can be visualized only when all the keys for the parties related to the secret information are prepared. There is a unique effect that it can be increased.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of an electronic bidding system to which the present invention is applied.
FIG. 2 is a diagram illustrating the relationship among various modules included in the procurement-side apparatus according to the present embodiment.
FIG. 3 is a diagram illustrating the relationship between various modules included in a supply-side apparatus according to the present embodiment.
FIG. 4 is a sequence chart showing operational procedures from bidding to bid opening in the electronic bidding system of the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic bidding system 10 Procurement side apparatus 151 Bid permission module 152 Mail transmission instruction module 153 Web release instruction module 154 Bid reception module 155 Decryption key storage module 156 Open bid determination module 157 Open bid module 158 Decryption module 159 Display module 20 Supply side apparatus 251 Bid participation application module 252 Key pair creation module 253 Email transmission command module 254 Key acquisition module 255 Bid document creation module 256 Encryption module L Internet

Claims (5)

A bidding system comprising a supply side device for participating in a bid, and a procurement side device connected to the supply side device via a network,
The supply side device includes:
A key creation means for creating a pair of an encryption key and a decryption key;
Means for transmitting the encryption key created by the key creation means to the procurement side device via the network;
Key acquisition means for acquiring all the encryption keys by acquiring the encryption key disclosed by the procurement side device via the network;
Encryption means for encrypting bid documents with the encryption keys of all bid devices acquired by the key acquisition means;
Means for transmitting the bid document encrypted by the encryption means to the procurement side device via the network;
Means for transmitting the decryption key created by the key creation means to the procurement side device via the network;
The procurement side device is:
Means for publishing on the network the encryption key transmitted from each of the bid side procurement side devices;
Means for acquiring an encrypted bid document and a decryption key transmitted from each of the bid side procurement side devices;
And a means for decrypting the tender document encrypted by the encrypting means with the decryption keys of all the procurement-side devices of all the bid-side devices transmitted. A first device for encrypting the secret information, is connected via the first device and the network, said a secret information holding system comprising a second device for holding the secret information,
The first device includes:
A key creation means for creating a pair of an encryption key and a decryption key;
Means for transmitting the encryption key created by the key creation means to the second device via the network;
Key acquisition means for acquiring the encryption key disclosed by the second device via the network;
Encryption means for encrypting secret information with the encryption keys of all the first devices acquired by the key acquisition means;
Means for transmitting the secret information encrypted by the encryption means to the second device via the network;
Means for transmitting the decryption key created by the key creation means to the second device via the network;
The second device includes:
Means for releasing the encryption key transmitted from each first device on the network;
Means for obtaining encrypted secret information and a decryption key transmitted from each of the first devices;
And a means for decrypting the encrypted secret information with the decryption keys of all the transmitted first devices. A supply-side device in a bid system comprising a supply-side device for participating in a bid, and a procurement-side device connected to the supply-side device via a network,
A key creation means for creating a pair of an encryption key and a decryption key;
Means for transmitting the encryption key created by the key creation means to the procurement side device;
Key acquisition means for acquiring an encryption key disclosed by the procurement side device via the network;
Encryption means for encrypting bid documents with encryption keys of all supply side devices acquired by the key acquisition means;
Means for transmitting the bid document encrypted by the encryption means to the procurement side device via the network;
Means for transmitting the decryption key created by the key creation means to the procurement side device via the network;
A supply-side device comprising: A procurement-side device in a bidding system comprising a supply-side device for participating in a bid and a procurement-side device connected to the supply-side device via a network,
Means for publishing on the network the encryption key transmitted from the bidding device via the network;
Means for obtaining a bid document and a decryption key, which are transmitted from each bid-side device via the network and encrypted with the encryption keys of all bid-side devices of each bid-side device;
And a means for decrypting the tender documents encrypted by the encryption means with all the decryption keys transmitted from the bid-side apparatuses of all the procurement-side apparatuses via the network. Side device. A first device for encrypting the secret information, is connected via the first device and the network, a secret information storage method in the secret information holding system comprising a second device for holding the secret information ,
In the first device,
Creating an encryption key and decryption key pair;
Transmitting the encryption key created by the step to the second device via the network;
Obtaining encryption keys of all first devices disclosed by the second device;
Encrypting secret information with all encryption keys acquired in the step;
Transmitting the secret information encrypted in the step to the second device via the network;
Transmitting the created decryption key to the procurement side device via the network, and
In the second device,
Publishing on the network the encryption key transmitted from each of the first devices;
Obtaining encrypted secret information and a decryption key transmitted from each of the first devices;
And a step of decrypting the encrypted secret information with the transmitted decryption keys of all the first devices.

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