KR100377196B1 - System and method for key recovery using multiple agents - Google Patents

Abstract

The present invention uses a multi-agent to recover encrypted communication and stored information, and by using a multi-agent key recovery system to secretly specify any key recovery agent from the agent group to increase the time and security of key recovery In order to provide the method, a key recovery block (KRB), which is information necessary for performing key recovery, is received from a key recovery information generation system, and a key recovery request is performed by a key recovery means, and restored through the key recovery means. Key recovery request means for receiving the received key information; Partial key information is extracted from the information received from the key recovery requesting means, the extracted partial key information is transmitted to the corresponding partial key recovery means, and the partial key recovery is requested, and each of the recovered partial received from the partial key recovery means. Key recovery means for delivering the recovered key information by combining key information to the key recovery requesting means; And a plurality of partial key recovery means for receiving partial key information received from the key recovery means, for recovering partial key information, and for transferring each of the recovered partial key information to the key recovery means. Used for information systems using cryptographic communication, such as ERP, CITIS, e-mail, electronic payment, and electronic money.

Description

System and method for key recovery using multiple agents

The present invention relates to a key recovery system using a multi-agent and a method and a computer-readable recording medium recording a program for realizing the method, in particular by using a multi-agent to recover encrypted communication and stored information The present invention relates to a key recovery system using multiple agents for enabling secret key assignment from a group of agents, and a method and a computer-readable recording medium having recorded thereon a program for realizing the method.

The present invention belongs to the field of encryption key management technology in the information protection system of the information technology field, and specifically belongs to the field of encryption key recovery technology. The present invention can be utilized for the recovery of encrypted information through the recovery of the encryption key in all information systems using encryption technology, e-commerce, light transaction (CALS: Commerce At Light Speed), enterprise resource planning (ERP), It can be used in various applications such as enterprise information system (EIS), electronic mail, electronic payment, and electronic money.

The security of information in the information system is very important, and information security systems have been developed and operated in the information system. Information security systems encrypt and communicate sensitive information using a large number and amount of encryption keys (16 to 344 bytes per key). Therefore, information systems must manage a large number of cryptographic keys. However, since encrypted information cannot be recovered when a cryptographic key (especially a private key or session key) is lost or damaged, or the person who owns the cryptographic key cannot be found within a certain time, a technique for recovering it is required. do. In addition, there is a need for a technology capable of decrypting encrypted information in accordance with the organization's security policy and law enforcement.

The prior art in the field of key recovery technology is a key entrustment method in which a receiver entrusts its cryptographic key to one or more key entrusting agencies and requests the entrusted key if a key recovery is required, and the TTP (Trusted Third Party) A TTP method that provides an encryption key to the recipient and when the key needs to be recovered, the TTP re-provides the key provided to the recipient by the receiver. The receiver symmetrically encrypts the data, encrypts the session key with its public key, and maintains the encrypted data together. The receiver's private key is stored in a key backup authority.When key recovery is needed, a commercial key backup method in which the key recovery authority provides the stored recipient's private key.The key recovery information is generated using a symmetrically encrypted session key. The recovery information can only be decrypted by the key recovery agent. When key recovery is required, the key recovery information is sent to the key recovery agent to recover the session key. Keys can be divided into the encapsulation and more. However, key consignment agencies in key consignment, TTP, and commercial key backup methods, key distribution centers and key backup institutions in TTP can be bottlenecks in information systems that have frequent transactions and store information such as e-commerce systems, and most of them Recipients do not attempt to entrust or store their private or session keys with any organization.

In particular, the key entrustment method has a problem of being vulnerable to privacy and binding problems of individuals. In key encapsulation, receivers generate and store key recovery information, and request key recovery centers with key recovery information only when key recovery is needed, reducing system bottlenecks, and allowing each recipient to take the initiative to recover keys. Can be guaranteed. However, even in the existing key encapsulation methods, there are various problems such as eavesdropping and spoofing of the agent by fixing one or two key recovery agents. Looking at the problem in detail as follows.

First, the session key processing method is not known in a multi-agent-based key recovery system utilizing n key recovery agents.

Secondly, since the receiver (key recovery requester) knows the identity of the key recovery agent designated by the sender (key recovery information generator), transparency of key recovery is degraded.

Third, since key recovery agents are determined, collusion attacks between agents are easy.

Finally, the receiver must communicate directly with multiple key recovery agents and complex key recovery functions must be installed for each recipient.

The present invention has been proposed to solve the above problems, and by using multiple agents to recover encrypted communication and stored information, it is possible to secretly designate any key recovery agent from a group of agents so that time of key recovery can be achieved. SUMMARY OF THE INVENTION An object of the present invention is to provide a key recovery system using multiple agents and a method thereof, and a computer-readable recording medium recording a program for realizing the method.

1 is a diagram illustrating an embodiment of a key recovery protocol using multiple agents according to the present invention.

2A and 2B are explanatory diagrams illustrating an intermediate key generation process according to the number of key recovery agents selected in a key recovery system using multiple agents according to the present invention.

3 is an explanatory diagram of a communication structure between domains and parts according to the present invention;

4 is a block diagram of an embodiment of a key recovery system using multiple agents according to the present invention;

5 is a diagram illustrating an embodiment of a user key recovery system among key recovery systems using multiple agents according to the present invention;

6 is a diagram illustrating an embodiment of a key recovery center system among key recovery systems using multiple agents according to the present invention;

7 is a diagram illustrating an embodiment of a key recovery agent system among key recovery systems using multiple agents according to the present invention;

* Explanation of symbols for the main parts of the drawings

41: User Key Recovery System 42: Key Recovery Center System

43: Key Recovery Agent System

In the present invention for achieving the above object, in a key recovery system using a multi-agent, the key recovery block (KRB), which is information required to perform key recovery from the key recovery information generation system received from the key recovery block key recovery means Key recovery request means for performing a request and receiving the recovered key information through the key recovery means; Partial key information is extracted from the information received from the key recovery requesting means, the extracted partial key information is transmitted to the corresponding partial key recovery means, and the partial key recovery is requested, and each of the recovered partial received from the partial key recovery means. Key recovery means for delivering the recovered key information by combining key information to the key recovery requesting means; And a plurality of partial key recovery means for receiving partial key information received from the key recovery means, for recovering partial key information, and for transmitting the recovered partial key information to the key recovery means. .

In addition, the present invention, in a key recovery method applied to a key recovery system using a multi-agent, the user key recovery system delivers a key recovery block (KRB) which is information required to perform key recovery from the key recovery information generation system A first step of requesting key recovery to a key recovery center; A second step of the key recovery center extracting partial key information according to a key recovery request from the user key recovery system and transferring the extracted partial key information to a corresponding key recovery agent to request partial key recovery; A third step of each of the key recovery agents recovering the corresponding partial key information according to the partial key recovery request from the key recovery center and transferring each recovered partial key information to the key recovery center; And a fourth step in which the key recovery center combines the partial key information received from each of the key recovery agents and delivers the recovered key information to the user key recovery system.

In addition, the present invention, the key recovery system using a multi-agent equipped with a processor, the key recovery block (KRB) that is required for the user key recovery system to perform the key recovery from the key recovery information generation system received key recovery A first function of requesting key recovery to a center; A second function of requesting partial key recovery by the key recovery center extracting partial key information according to a key recovery request from the user key recovery system and transferring each extracted partial key information to a corresponding key recovery agent; A third function, wherein each key recovery agent recovers the corresponding partial key information according to a partial key recovery request from the key recovery center, and delivers each recovered partial key information to the key recovery center; And a program for realizing a fourth function for the key recovery center to combine the partial key information received from each of the key recovery agents to deliver the recovered key information to the user key recovery system. Provide the medium.

The present invention relates to a key recovery system and method using multiple agents, and improves security by enabling the randomization of any key recovery agent from a plurality of agents, that is, a group of agents, and has the following features.

First, the key recovery system has a key recovery function using multiple agents.

Second, the key recovery system has a secret function of two or more key recovery agents from the key recovery agent family in the protocol.

Third, the key recovery system has a dynamic public key distribution function by the certificate attachment method in the protocol.

Fourth, it has a function of generating a new key pair by a receiver (key recovery requester) in the protocol.

Fifth, the protocol has a function of selecting a key recovery service.

The present invention can contribute to improving the availability of all information systems utilizing the information protection technology, it is characterized in that to increase the time and security of key recovery.

On the other hand, the present invention provides a key recovery system that can solve the encrypted information through the recovery of the first lost or lost key with a minimum of time and resources (computer and communication resources). Second, the present invention can be a target of security attacks on malicious subjects (general recipients, key recovery centers and key recovery agencies, etc.) in the information system, so that the encrypted information can be decrypted without the legal owner of the encrypted information. We present a key recovery system that can secure the security of the system. Third, since an information system such as an e-commerce system can be operated not only within one institution but also internationally, the present invention secures interoperability and international standards that must be interoperated between various platforms and different information systems formed through the Internet. Present a key recovery system that complies with.

In other words, the present invention utilizes existing cryptographic algorithms whose safety has been verified, enhances security more efficiently, provides a new multi-agent-based key recovery protocol that satisfies interoperability and conforms to international standards, and a key implementing the protocol. It is characterized by providing a recovery system.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a key recovery system that uses multiple agents to recover encrypted communications and stored information, and improves security by allowing any key recovery agent to be secreted from a plurality of agents, i. It consists of the following details:

First, the key recovery protocol implementation method using multiple agents is as follows.

1 is a diagram illustrating an embodiment of a key recovery protocol using a multi-agent according to the present invention, which is shown as a sequence diagram in UML (Unified Modeling Language).

As shown in FIG. 1, a key recovery technique using multiple agents is a technique for configuring a key recovery system by designating n key recovery agents larger than two. In a key recovery system using multiple agents (that is, a system consisting of n key recovery agents), the session key (m bits) is not divided into m / n bits, but n intermediate numbers using n-1 random keys and session keys. By generating keys (m bits), the security of the session key is increased.

In the protocol of FIG. 1, the fork function of Equation 1 generates intermediate keys ik by dividing the session key by the number of key recovery agents using the session keys sks and the random numbers rks. The join function in Equation 2 is to combine the partial keys. One partial key is generated per key recovery agent, and one random key is generated less than the selected number of key recovery agents.

Where ik ₁ = ssk rk ₁ , ik ₂ = rk ₁ rk ₂ ,.. , ik _i = rk _i-1 rk _i ,… , ik _n = rk _n-1 )

ik2 … iki … ikn

Where ssk: session key, rk: random number key, ik: middle key, Bitwise exclusive-or operator)

Thus, a table showing the key recovery protocol processing process using a multi-agent as shown in Table 1 below.

Where "n" is the number of specified key recovery agents (KRAs), "+" is the combination of messages, "ssk" is the session key, "puk _x " is the public key of x, and "prk _x " is the private key of x , "SCe (d, k)" symmetrically encrypts data d with key k (e.g. DES), "SCd (d, k)" symmetrically decrypts d with key k, "PCe (d, k) "Is asymmetric encryption with key k (eg RSA)," PCd (d, k) "is asymmetric decryption with key k," KRI "is key recovery information," RES "is partial key information Indicates.

2A and 2B are explanatory diagrams illustrating an intermediate key generation process according to the number of key recovery agents selected in a key recovery system using multiple agents according to the present invention.

As shown in Fig. 2a and 2b, the sender encrypts each intermediate key (ik _i ) with the public key of the corresponding key recovery agents, each key recovery agent decrypts it with its own private key and sends it to the key recovery center. The key recovery center recovers the session key through a join operation. On the other hand, when you have n key recovery agents, (ssk rk ₁ ) (rk ₁ rk ₂ ) ,… , (rk _i-1 rk _i ),… , (rk _n-2 rk _n-1 ) Since rk _n-1 = ssk, the session key (ssk) is preserved.

Secondly, a method of specifying secrets of two or more key recovery agents from the key recovery agent group in the protocol is as follows.

As in FIG. 1, the sender (creator of key recovery information) secretly designates a number of key recovery agents and inserts information about it in the key recovery block KRB. This prevents the receiver from knowing (or not needing to know) the key recovery agent. Thus, the recipient only needs to know the public key of the key recovery center. This provides the recipient (key recovery requester) with transparency of key recovery and reduces the likelihood of collusion between parts. On the other hand, the key recovery block (KRB) is more precisely described as Key Recovery Information (KRI). Information), including additional information (version, length, OID, type, etc.), plus a signature value for integrity verification. In other words, KRI is a key component of KRB.

Third, the dynamic public key distribution method by the certificate attachment method in the protocol will be described as follows. In other words, the certificate containing the public key is distributed to the necessary place at the required time.

The following certificates use a static distribution scheme of certificates obtained through the public key infrastructure in which the present invention operates. In the case of the sender (key recovery information generator), the certificate of the recipient and key recovery center and the designated key recovery agents, In the case of a receiver (key recovery service requester), a certificate of a key recovery center is used. In the case of a key recovery center, a certificate of a key recovery agent is used.

The remaining certificates use a dynamic distribution of certificates that are sent with key recovery information only when and where they are needed. First, in the case of the key recovery center, when the receiver requests key recovery, the receiver's certificate is obtained from the key recovery request message. In other words, the recipient's certificate is attached to the key recovery request message. Next, in the case of the key recovery agent, when the key recovery center requests key recovery, the key recovery center obtains a certificate of the key recovery center from the key recovery request message. That is, the key recovery center's certificate is attached to the key recovery request message.

In general, in a key recovery system, the number of potential recipients (key recovery requesters) can be tens of thousands or more, and thus, the key recovery center does not need to acquire all recipients' certificates in advance, and according to the present invention, Can be reduced.

Fourth, a method of generating a new key pair by a receiver (key recovery requester) in the protocol is as follows.

That is, since the receiver (key recovery requester) has lost his or her private key, a new key pair (public key and private key) is generated, registered with the certificate authority, and used. Therefore, the public key of the receiver which has illegally obtained the recipient's private key or whose usage period has expired cannot be used.

Finally, a method of selecting a key recovery service in the protocol is as follows.

Since the key recovery service is very sensitive to the general receiver of the information system, the present invention allows the sender and the receiver, who are the owners of the information, to select it as shown in FIG. Through this, the utility of the present invention can be increased.

3 is an explanatory diagram illustrating a communication process between domain parts and parts according to the present invention.

As shown in Fig. 3, ① denotes communication between a receiver not receiving a key recovery service, ② denotes communication between a receiver not receiving a key recovery service and a receiver receiving a service, ③ denotes communication between a receiver receiving a key recovery service, and ④ Communication for the key recovery service, ⑤ indicates communication between the key recovery center KRC and the key recovery agent KRA, and communication between the key recovery agents KRA _i to KRA _n (not allowed).

On the other hand, the key recovery system is not a proprietary system, but a solution for providing a key recovery service in the existing application system, the domain structure is shown in FIG.

"Application System Domain" refers to the Commerce At Light Speed (CALS), Electronic Commerce (EC), Electronic Data Interchange (EDI), and Contractor Integrated Technical Information Service (CITIS) systems, and above the Internet / Intranet infrastructure and public key infrastructure. It exists, and the general recipients are on this domain.

The "key recovery request domain" resides inside the application system domain, and recipients who are authorized to receive key recovery services reside on this domain. Within the key recovery request domain, there is a "key recovery providing domain" that provides a key recovery service, and is composed of one key recovery center and two or more key recovery agents. Nested domains, such as key recovery provisioning domains, inherit the functions of the parent domain.

4 is a diagram illustrating an embodiment of a key recovery system using multiple agents according to the present invention.

As shown in FIG. 4, in the key recovery system using the multi-agent according to the present invention, the user key recovery system 41 for requesting a key recovery request from the key recovery center system when the receiver loses the key for decrypting the ciphertext. And a key recovery center system 42 for requesting a key recovery agent for partial key recovery to perform a key recovery requested by the receiver, and a plurality of key keys for performing the partial key recovery requested from the key recovery center system 42. A key recovery agent system 43 configured as a key recovery agent is provided.

Here, a key recovery procedure of a key recovery system using multiple agents is as follows.

First, when a sender transmits a ciphertext (including an electronic signature and an encrypted session key) and a key recovery block (KRB) which is information required to perform key recovery, the receiver receives the ciphertext. However, if the receiver loses a key capable of decrypting the cipher text, the receiver sends the KRB to the key recovery center system 42 to make a key recovery request.

Then, the key recovery center system 42 extracts the partial key information from the KRB received from the receiver and transmits the partial key information to the corresponding key recovery agent system 43.

Accordingly, the key recovery agents recover the partial key information received from the key recovery center system 42 and then transmit the partial key information back to the key recovery center system 42.

The key recovery center system 42 combines the recovered partial key information received from the key recovery agents and transmits the recovered key information to the user key recovery system 41 so that the receiver can receive it.

5 is a configuration diagram of an embodiment of a user key recovery system among key recovery systems using multiple agents according to the present invention.

As shown in FIG. 5, the user key recovery system 41 of the key recovery system using the multi-agent according to the present invention is provided with respect to a certificate, a certificate format, a signature or encryption algorithm, a key recovery agent list, and the like transmitted through a storage unit. Initialization module 510 for initializing system and personal information, authentication module 520 for performing user authentication by password after performing initialization module 510, and after performing authentication module 520 Generate recovery information, create additional key recovery information to generate key recovery blocks, perform integrity verification on the generated key recovery blocks, deliver the verified key recovery blocks to the key recovery center, and deliver Key recovery module 530 for decrypting the session key to perform key recovery, and the key recovery request of the recipient authenticated through the authentication module 520 to create and deliver A key recovery request module 540 for receiving the key recovery information received from the key recovery module 530 and the key recovery request module 540 and stored in a storage unit and communicating with a key recovery center Module 550.

Here, the initialization module 510 includes a system information initialization unit 511 for initializing system information about a certification authority (CA) certificate, a certificate format, a signature or encryption algorithm, a key recovery agent list, and the like, which are transmitted through a storage unit, and a receiver. A personal information initialization unit 512 for initializing personal information about a certificate, a certificate format, a signature or encryption algorithm, a recipient private key, and the like.

The authentication module 520 includes a user authentication unit 521 for performing user authentication using a password by using the information initialized through the initialization module 510.

The key recovery module 530 separates the session key used to encrypt the transmission document through the authentication module 520, encrypts each of the key recovery agents with a public key selected from a group of key recovery agents, and then encrypts the public key of the key recovery center. In this case, the key recovery information generation unit for generating key recovery information by attaching a key recovery agent ID (ID) and a receiver ID (ID) to be used for selecting the key recovery agent and verifying the owner of the key recovery information in the key recovery center. 531 and a key recovery block generation unit 532 for setting additional information to the key recovery information generated by the key recovery information generation unit 531 and generating a signature for verifying the key recovery block generator as its own private key. And a key recovery block for performing integrity verification on the key recovery block generated or received through the key recovery block generation unit 532 with the sender's public key. A key recovery information transmission unit 534 for delivering the key recovery block verified through the key recovery block verification unit 533 to the receiver or the key recovery center, and a session key received from the key recovery center. A receiver key recovery unit 535 for decrypting the data with its own private key to perform key recovery.

The key recovery request module 540 forwards the key recovery request generation unit 541 to generate a key recovery request for the key recovery request, and an encrypted and signed key recovery request to the key recovery center through the communication module 550. Key recovery request delivery unit 542 for the.

The communication module 550 includes an output unit 551 for outputting data to the outside and an input unit 552 for receiving data from the outside.

6 is a diagram illustrating an embodiment of a key recovery center system among key recovery systems using multiple agents according to the present invention.

As shown in FIG. 6, the key recovery center system of the key recovery system using the multi-agent according to the present invention includes system and administrator information about a certificate, a certificate format, a signature or an algorithm, a key recovery agent, and the like, which are transmitted through a storage unit. Initialization module 610 for initializing, authentication module 620 for performing administrator authentication by password after performing initialization module 610, and decrypting the request details by decrypting the key recovery request received from the key recovery requester. A partial session key request to be sent to key recovery agents to perform partial key session key recovery, and a plurality of corresponding encrypted partial session keys extracted from the key recovery information together with the generated partial session key recovery request. Key recovery request module 630 for transmitting to the key recovery agent of the key, and the key received from the key recovery requester An encrypted partial session extracted from the recovery information by performing integrity verification on the recovery block, extracting the owner ID from the key recovery information, checking the certificate and request ID, and decrypting the verified key recovery information with the public key of the key recovery center. The key recovery module 640 sends a key to the corresponding key recovery agents, recovers the partial session key received from the agents, and records the information about the key recovery requester's access to audit the repaired details. An audit module 650 for storing in a log, a communication module 660 for communicating with key recovery agents, an authentication module 670 for performing administrator authentication with a password, and an authentication module 670 After performing authentication through the system access management operation to manage the recovery history, there is provided with a management module 680 for managing the error accordingly The.

Here, the initialization module 610 is a system information initialization unit 611 for initializing information on a certification authority (CA) certificate, a certificate format, a signature or encryption algorithm, a key recovery agent list, and the like, which are transmitted through a storage unit, and key recovery. And an administrator information initialization unit 612 for initializing administrator information on the center administrator certificate, certificate format, signature or encryption algorithm, administrator private key, and the like.

The authentication module 620 of the operating system includes an administrator authentication unit 621 for performing administrator authentication using a password using information initialized through the initialization module 611, and a certificate of a requestor received from a key recovery requester. Requestor authentication unit 622 for verification by a certificate.

The key recovery request module 630 decodes the key recovery request received from the key recovery requester to confirm and process the request details, and to the key recovery agents to perform partial session key recovery. The encrypted partial session extracted from the key recovery information together with the partial key recovery request generation unit 632 for generating a partial session key request to be transmitted and the partial session key recovery request generated through the partial key recovery request generation unit 632. Partial key recovery request delivery unit 633 for transmitting the key to the corresponding key recovery agents.

The key recovery module 640 may include a key recovery block verification unit 641 for performing integrity verification on the key recovery block received from the key recovery requester, and key recovery information verified through the key recovery block verification unit 641. Key recovery information, which is obtained through the key recovery information owner verification unit 642 and the key recovery information owner verification unit 642, to extract the owner ID and verify that the certificate ID and the request ID are the same. A key recovery information processing unit 643 for decrypting the public key of the local key, a partial key integrity generating unit 644 for generating an integrity value for the partial session key processed through the key recovery information, and a partial key integrity generating unit 644 Partial key recovery information for delivering the encrypted partial session key extracted from the key recovery information to the corresponding key recovery agents together with the partial session key recovery request generated through 645, a center key recovery unit 646 for recovering the session key by recovering the partial session key received from the corresponding key recovery agents, and a key recovered through the center key recovery unit 646 It includes a recovery key delivery unit 647 for delivering to the requestor.

The audit module 650 generates an access log generating unit 651 for recording information on the access of the key recovery requestor, and an audit log for storing the details of the recovery processing through the recovery key delivery unit 647 in the audit log. A portion 652 is included.

The communication module 660 includes an input unit 661 for receiving data from the outside and an output unit 662 for outputting data to the outside.

The authentication module 670 of the management system includes an administrator authentication unit 671 that performs administrator authentication using a password, and the management module 680 manages a system environment using information authenticated through the authentication module 670. The system environment management unit 681 for performing the operation, the system access management unit 682 for performing the system access management operation using the information authenticated through the authentication module 670, and the authentication module 670 A recovery history management unit 683 for performing a recovery history management operation using the information, and a recovery error management unit 685 for performing a recovery error management operation using information authenticated through the authentication module 670. .

7 is a diagram illustrating an embodiment of a key recovery agent system among key recovery systems using multiple agents according to the present invention.

As shown in FIG. 7, a key recovery agent system among key recovery systems using multiple agents according to the present invention includes system and administrator information on a certificate, a certificate format, a signature or encryption algorithm, a key recovery agent, and the like, which are transmitted through a storage unit. Initialization module 710 for initializing the operation, authentication module 720 for performing administrator authentication by password after performing the initialization module 710, and the request history by decrypting the key recovery request received from the key recovery center A key recovery request module 730 for verifying and processing the data, and verifying the integrity of the partial key received from the key recovery center and recovering the partial key of the key recovery agent and recalling the encrypted and integrity values of the recovered partial key. Encrypt with the public key of the key recovery center, generate the integrity value with the private key of the key recovery agent, and then encrypt the recovered partial key. The key recovery module 740 for transmitting the converted value and the integrity value to the key recovery center, the information on the access of the key recovery center, and the recovered contents transmitted through the recovered partial key delivery unit 744. An audit module 750 for storing the information, a communication module 760 for communicating with the key recovery center, an authentication module 770 for performing administrator authentication with a password, and an authentication module 770. After performing authentication, a management module 780 for managing a recovery history by performing a system access management operation and managing an error accordingly is provided.

Here, the initialization module 710 may include a system information initializer 711 for initializing information on a CA certificate, a certificate format, a signature or encryption algorithm, a key recovery agent list, and the like, and a key recovery agent manager certificate, a certificate format, a signature, or the like. And an administrator information initialization unit 712 for initializing administrator information on an encryption algorithm, an administrator private key, and the like.

The authentication module 720 of the operating system includes an administrator authentication unit 721 for performing administrator authentication using a password using information initialized through the initialization module 710.

The key recovery request module 730 includes a partial key recovery request processing unit 731 for verifying and processing the request details by decrypting the key recovery request received from the key recovery center.

The key recovery module 740 decrypts the partial key integrity verification unit 741 for verifying the integrity of the partial key received from the key recovery center and the partial key received from the key recovery center with the private key of the key recovery agent. The agent partial key recovery unit 742 for recovering the key and the partial key recovered through the agent partial key recovery unit 742 are encrypted with the public key of the key recovery center and an integrity value is generated and processed with the private key of the key recovery agent. A recovered partial key processing unit 743 for transmitting the encrypted and integrity values of the recovered partial key to the key recovery center through the recovered partial key processing unit 743 It includes.

The audit module 750 includes an access log generator 751 for recording information about access of the key recovery center, and an audit for storing the details of the recovery process through the recovered partial key transfer unit 744 in the audit log. And a log generator 752.

The communication module 760 includes an input unit 761 for receiving data from the outside and an output unit 762 for outputting data to the outside.

The authentication module 770 of the management system includes an administrator authentication unit 771 for performing administrator authentication using a password, and the management module 780 manages a system environment using information authenticated through the authentication module 770. Through a system environment management unit 781 for performing a task, a system access management unit 782 for performing a system access management task using information authenticated through the authentication module 770, and an authentication module 770. A recovery history management unit 783 for performing a recovery history management operation using the authenticated information, and a recovery error management unit 785 for performing a recovery error management operation using information authenticated through the authentication module 770; Include.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

The present invention as described above, by using multiple agents to recover the encrypted communication and stored information first, it is effective to increase the time and security of key recovery by secretly specifying any key recovery agent from the agent group have.

Second, the new multi-agent-based key recovery protocol and the key recovery system that implement this protocol can be used more effectively by using existing cryptographic algorithms that have been proven to be more secure. There is an effect that can be provided.

Third, it was developed as a solution for recovering electronic documents in CALS, e-commerce, and CITIS infrastructure, but it can be applied to all information systems using crypto communication.

Fourth, by adding a sender subsystem according to the present invention to an existing output processor and adding a receiver subsystem to the input processor, there is an effect of recovering encrypted stored information. That is, the output processor can encrypt the information to be stored, generate the key recovery information, and store it on the disk along with the encrypted information.In key recovery, the input process (key recovery requester) sends the key recovery information to the key recovery center to recover the key. can do.

Claims (15)

In a key recovery system using multiple agents, A key for receiving a key recovery block (KRB), which is information necessary for performing key recovery from a key recovery information generation system, performing a key recovery request to a key recovery means, and receiving a key information recovered through the key recovery means. Recovery request means; Partial key information is extracted from the information received from the key recovery requesting means, the extracted partial key information is transmitted to the corresponding partial key recovery means, and the partial key recovery is requested, and each of the recovered partial received from the partial key recovery means. Key recovery means for delivering the recovered key information by combining key information to the key recovery requesting means; And A plurality of partial key recovery means for receiving partial key information received from the key recovery means to recover partial key information, and for transmitting each of the recovered partial key information to the key recovery means; Key recovery system using a multi-agent including a. The method of claim 1, The key recovery information generation system, A key recovery system using multiple agents, characterized in that a plurality of key recovery agents are secretly designated and inserted into a key recovery block. The method according to claim 1 or 2, The key recovery request means, the key recovery means and the plurality of partial key recovery means, In order to distribute a certificate containing a public key to a necessary place at a necessary time, in the case of the key recovery means, the key recovery request means obtains a certificate of the key recovery request means from a key recovery request message when the key recovery request means requests a key recovery. And in the case of the partial key recovery means, obtain a certificate of the key recovery means from the partial key recovery request message according to a request from the key recovery means. The method of claim 3, wherein The certificate is, Key recovery system using a multi-agent, characterized in that it includes information such as public key, identifier. The method according to claim 1 or 2, The key recovery request means, A multi-agent characterized in that a new key pair (public key and private key) is generated to register a public key and a private key with a certificate authority so that a public key that is illegally obtained or has expired cannot be used. Key recovery system. The method according to claim 1 or 2, The key recovery request means, And a key recovery information generating system (sender) and said key recovery requesting means (receiver), which are owners of information, to select a key recovery service. In the key recovery method applied to a key recovery system using a multi-agent, A first step in which the user key recovery system receives a key recovery block (KRB), which is information necessary for performing key recovery from the key recovery information generation system, and requests a key recovery center from the key recovery center; A second step of the key recovery center extracting partial key information according to a key recovery request from the user key recovery system and transferring the extracted partial key information to a corresponding key recovery agent to request partial key recovery; A third step of each of the key recovery agents recovering the corresponding partial key information according to the partial key recovery request from the key recovery center and transferring each recovered partial key information to the key recovery center; And A fourth step in which the key recovery center combines the partial key information received from each of the key recovery agents and delivers the recovered key information to the user key recovery system; Key recovery method using a multi-agent including a. The method of claim 7, wherein The key recovery information generation system, And recovering the plurality of key recovery agents secretly and inserting the plurality of key recovery agents into a key recovery block. The method according to claim 7 or 8, The key recovery request process of the first step, the key recovery request process of the second step, and the partial key information recovery process of the third step, In order to distribute the certificate containing the public key to the necessary place at the required time, the key recovery center obtains the certificate of the user key recovery system from the key recovery request message when the user key recovery system requests the key recovery. Each key recovery agent obtains a certificate of the key recovery center from a partial key recovery request message according to a request from the key recovery center. The method of claim 9, The certificate is, Key recovery method using a multi-agent, characterized in that it comprises information such as public key, identifier. The method according to claim 7 or 8, The key recovery request process of the first step, Generate and generate a new key pair (public key and private key) of the user key recovery system so that the public key of the user key recovery system which has illegally obtained the private key of the user key recovery system or whose usage period has expired cannot be used. Recovering a key using a multi-agent, characterized in that the registered public key and private key registered with the certificate authority. The method according to claim 7 or 8, The key recovery request process of the first step, A key recovery method using multiple agents, characterized in that the key recovery information generation system (sender) and the user key recovery system (receiver), which are owners of information, can select a key recovery service. The method of claim 7, wherein The key recovery information generation system, The following fork function for generating intermediate keys (ik) by dividing the session key by the number of key recovery agents using the session keys (ssk) and random numbers (rk), and the following join that combines partial keys A method for recovering keys using multiple agents, wherein a function is used, one partial key is generated per key recovery agent, and one random key is generated less than the selected number of key recovery agents. (fork (ssk, n) = ik ₁ , ... ik _i ,…, ik _n (where ik ₁ = ssk rk ₁ , ik ₂ = rk ₁ rk ₂ ,.. , ik _i = rk _i-1 rk _i ,… , ik _n = rk _n-1 ), join (ik ₁ ,…, ik _i ,…, ik _n ) = ik ₁ ik ₂ … ik _i … ik _n (where ssk: session key, rk: random number key, ik: middle key, Bitwise exclusive-or operator) The method of claim 13, The session key is In the partial key recovery system using a multi-agent (system composed of n key recovery agents), n intermediate keys (m bits) are generated using n-1 random numbers and session keys without partitioning into m / n bits. Key recovery method using a multi-agent, characterized in that. In a key recovery system using a multi-agent with a processor, A first function of requesting key recovery to a key recovery center by receiving a key recovery block (KRB) which is information necessary for a user key recovery system to perform key recovery from a key recovery information generation system; A second function of requesting partial key recovery by the key recovery center extracting partial key information according to a key recovery request from the user key recovery system and transferring each extracted partial key information to a corresponding key recovery agent; A third function, wherein each key recovery agent recovers the corresponding partial key information according to a partial key recovery request from the key recovery center, and delivers each recovered partial key information to the key recovery center; And A fourth function of delivering the recovered key information to the user key recovery system by combining the partial key information received from each of the key recovery agents by the key recovery center; A computer-readable recording medium having recorded thereon a program for realizing this.