KR100406008B1 - Real time certificate revocation list transmitting method and system on wireless communication - Google Patents

Abstract

The present invention relates to a method and system for transmitting a certificate revocation list in real time using FM additional broadcasting. The real-time certificate revocation list transmission method of the present invention generates a certificate revocation list that is no longer used in a method of transmitting a certificate revocation list to a user's communication device through a broadcast-enabled wireless transmission system. The certificate revocation list is then provided to the wireless transmission system for transmission to the user's communication device. In this case, the certificate revocation list may include at least one of a wireless transmission field indicating a wireless transmission scheme, a group field indicating a user group, a frequency field indicating a frequency band, and a CRL classification field in an extension field.

Description

REAL TIME CERTIFICATE REVOCATION LIST TRANSMITTING METHOD AND SYSTEM ON WIRELESS COMMUNICATION}

The present invention relates to a method and system for transmitting a certificate revocation list in real time using FM additional broadcasting.

In a distributed network system for data processing, a method for identifying a communication device on a network before connecting to a system operation and a resource may be referred to as authentication. The purpose of the system's connection is, for example, to communicate with other users, to find secure information, or to use certain services. Generally, a distributed system includes several computer nodes interconnected to a communication medium. Computer nodes may include nodes that are directly connected by users, such as workstations, and nodes that execute special applications, such as servers. These nodes and the work performed on them and the users of the distributed system are treated as principals. Certificate exchange takes place for this main element.

Public key encryption is a secure communication method in which each main element has a public encryption key and a private encryption key. A cryptographic key is used with a cryptographic algorithm and is a code or number that defines a single transformation used to encrypt or decrypt data. The public key system can be used where the confidentiality of the information being transmitted, that is, ensure the reliability of the information sender and where the information should not be intercepted in the interim.

The manner in which the public key cryptosystem works for authentication can be understood without reference to the mathematical transformations used for encryption and decryption. Since the information encoded with the public key is decoded by a private key associated with it, on the contrary, since the information encoded with the private key is decoded by a public key associated with it, public key encryption is an asymmetric encryption method. . At this time, the associated secret key and public key mean a secret key / public key pair. By this encryption scheme, the public key is known to other principal elements in the system, but the secret key is known only to the owner of the key.

For secure transmission of information to the recipient, the principal element encodes (encrypts) the information using the recipient's public key. At this time, since only the recipient owns the corresponding private key, it is possible to decode (decode) the transmitted information. On the other hand, in order for the sender to identify itself to the recipient of the information, the sender encodes (signatures) the information using the secret key. Thus, if the receiver can decode (verify) the information using the sender's public key, the sender is normally assigned. In public key cryptography, each main element must know its own private key, and all public keys are located in a common place, such as a directory service (DS). On the other hand, each main element can have its own public key and provide it to the recipient during the authentication process.

Here, we need to know which public key belongs to which main element. A typical way to solve this problem is to use a trusted entity known as a Certificate Authority (CA). The CA is the subject, that is, the name of the principal element whose public key is verified, the certificate serial number, the name of the CA that issues the certificate, and the public key of the subject. And an identity certificate signed with a message indicating when the certificate expires. As such, verifying the relationship between the public key and the primary element to which the public key belongs prevents an attacker from invading the system by posing as if it were a valid primary element. Because each certificate is signed by a CA's private key to confirm its approval, the main element that wants to verify other principal elements on the network must know the CA's public key and sign the certificate in the certificate. You should be able to check. The certificate may be stored in a convenient location, such as a directory service (DS), or each node may store its own certificate and provide it during the authentication process. In general, for the sake of safety, a CA is an off-line entity and communicates with network elements using secure off-line communication technology.

For complete network security, all major elements must be certified. However, there should be a later revocation of the certificate before it expires after issuance. For example, the main element can be stolen, damaged or lost. In such a situation, the certificate should be revoked, making it impossible to verify by certificate.

Several methods have been proposed for revoking certificates that have not yet expired. One way is to store the certificates of all valid principal elements on the directory service (DS) and on-line locations and make them generally available. For example, if the user wants to connect to the server, the server checks whether the user's certificate exists in the directory service (DS). If the user's certificate does not exist in the directory service, it is determined that the certificate is revoked.

Another method is to issue a Certificate Revocation List (CRL), that is, a list of certificates that are no longer in use, from a Certificate Authority (CA). The Certificate Revocation List (CRL) is mentioned in ISO / IEC 9495-8 and has the format defined in ITU-T Rec. X.509.

Figure 1 shows the structure of an X.509 V2 certificate revocation list.

Referring to FIG. 1, the certificate revocation list is a basic field and includes a version, a signature algorithm id, an issuer name, an update date, a next date, and a revocation. It includes revoked certificates, certificate revocation list extensions (CRL extensions), and issuer signatures. The version represents the version of the certificate revocation list. The signature algorithm identifier includes the algorithm identifier used to sign the certificate revocation list. The issuer name is used to identify the certification authority that signs the certificate revocation list. The renewal date represents the issue date of the current certificate revocation list, and the next renewal date represents the issue date of the next certificate revocation list. The next renewal date means that the certificate revocation list can be issued within the indicated period, and not after that. A revocation certificate represents a list of revoked certificates, and includes a serial number of the certificate, a certificate revocation date, and a certificate revocation list entry field. The issuer signature includes an electronic signature for the certificate revocation list.

The certificate revocation list extension fields include the issuer key indentifier, the issuer alternative name, the certificate revocation list number (CRL number), the delta CRL indicator, and the issuing distribution point. It may include. In addition, the certificate revocation list entry extension field may include a reason code, a hold instruction code, an invalidity date, and a certificate issuer.

The application program included in the user's communication device is determined to be valid if the certificate has not expired and is not included in the current certificate revocation list CRL of the certification authority CA. However, if a number of certificates have been revoked and they belong to a Certificate Revocation List (CRL), then the Certificate Revocation List (CRL) will grow and therefore certificates to all network nodes that need the information contained in the Certificate Revocation List (CRL). The bandwidth, storage capacity, and certification authority (CA) processing power of the network for distributing revocation lists (CRLs) is consumed. Due to the difficulty in obtaining a certificate revocation list (CRL), the certificate revocation list (CRL) is not updated frequently and the expiration period is exceeded.

Another way to solve this problem is to use an On-Line Revocation Server (OLRS). The on-line revocation server (OLRS) has a database containing information about certificate revocation status. Information regarding the revocation status of a certificate may be included in the revoked certificate of the most recently issued version of the Certificate Revocation List (CRL) of the Certificate Authority (CA) and from a certificate that has not been expired from a Certificate Authority (CA). Contains real-time information about this. The on-line revocation server (OLRS) provides on-line certificate revocation information for the network principal element, and the network principal element may request certificate revocation information for the on-line revocation server (OLRS). That is, the network principal element requests an on-line revocation server (OLRS) for on-line revocation of the certificate revocation information, and the on-line revocation server (OLRS) responds to the retrieval based on information about the revocation status of the certificate. To provide. In this case, since the on-line revocation server (OLRS) responds to a specific on-line inquiry, the time may be shorter than the information provided by the off-line certification authority (CA), and the response signal is requested. Because only included information is included, more efficient information can be provided.

However, because the on-line revocation server (OLRS) performs work on-line and copies an entity, as the amount of connection increases, the safety decreases and the risk increases. Therefore, since the on-line revocation server (OLRS) is sensitive to the risks associated with the on-line processing, it is important to have a private key that is different from the CA. However, security by a private key of an on-line revocation server (OLRS) is less dangerous than security by a private key of a CA. The reason is that the risk of an online revocation server (OLRS) risk can be used to identify a principal whose certificates have already been revoked, or to identify a principal whose revocation certificates have been revoked. This is because the private key of the certification authority (CA) can issue an unauthenticated certificate.

In general, an on-line revocation server (OLRS) signs an inquiry result by using the on-line revocation server (OLRS) 's private key, and thus the on-line revocation server (OLRS) as an inquiry result for the main element. Check the certificate revocation status information. In addition, the Certificate Authority (CA) authenticates the trustworthiness of the private key of the on-line revocation server (OLRS) by issuing a Delegation certificate signed with the CA's private key along with the general certificate. . The representative certificate is issued to the corresponding main element to confirm that the on-line revocation server (OLRS) is authorized to issue certificate revocation status information. As such, a method of issuing a certificate revocation list (CRL) from a certification authority (CA) to a user, or issuing a certificate revocation list (CRL) using an on-line revocation server (OLRS) is a relatively simple user authentication method.

In addition, Korean Patent Publication No. 1999-025290 discloses an invention in which a certificate revocation list (CRL) can be searched in a certification authority in real time using a cache. Here, the certification authority manages the certificate revocation list by referring to the database of the certification authority when there is a certificate request from the user, and performs an authentication operation according to the request of the user.

The user who inquires the certificate revocation list stores the certificate revocation list (CRL) in memory until the next renewal period in order to reduce communication costs. The certificate revocation method may be a periodic revocation method and an immediate revocation method. The periodic revocation method does not allow CAs to securely announce the revocation of certificates within a regular period. To overcome this limitation, an immediate revocation method can be used. The immediate revocation method is not limited to the revocation information of the certificate in a time period, and can be immediately informed to the user. For this purpose, the user must verify the validity of the certificate through online transactions with the certificate authority (CA) that issued the certificate. . In particular, the requested information must not be altered by unauthorized users and transactions should be stable. However, this abolition method is difficult to implement this, there is a problem that the cost is expensive to implement.

That is, the certificate revocation list (CRL) issuing period determined by the certification authority (CA) should be sufficiently small without using a reliable server or security protocol. However, in the case of a large revocation list, there is a long time delay in reporting a compromise of trust to a certification authority (CA), and the issuance interval of the certificate revocation list is balanced between the distribution delay of the revocation list and the communication cost of frequent transmission. It should be set to achieve.

To solve this problem, you can use the delta-CRL method, which does not cover the entire certificate revocation list (CRL), but collects the list from when the certificate revocation list (CRL) is issued to when a new certificate revocation list is issued. have. By using the delta-CRL method, the user's certificate status processing time can be improved. In this way, the existing abolition information existing in the database is left as it is, and only the abolition information is added to the database. However, even when issuing a delta-CRL, the CA must issue a complete revocation list. That is, the delta-CRL cannot be issued without the entire certificate revocation list, and the certificate revocation list number of the delta-CRL and the entire certificate revocation list must be the same.

Both the CRL and delta-CRL schemes have a problem with the renewal period of the certificate revocation list. In addition, due to the spread of authentication, both CRLs and delta-CRLs are increasing in transmission volume, and various transmission problems are generated because the transmission time is also made at a predetermined time interval.

In order to solve this problem, an Online Certificate Status Protocol (OCSP) has recently been developed. The OCSP was developed to verify revocation and suspension status with accurate and real time verification of certificates. Since the OCSP is mainly important for data transaction, it can be used for the validation of real time certificates, for example, expensive securities information or expensive cash transactions. However, this OCSP also has a problem of generating a lot of transactions and server overload because it must process the validation of the certificate in real time.

On the other hand, in recent years, with the development of wireless communication technology, services using the wireless Internet as well as wireless communication have greatly increased. Accordingly, although data is transmitted using a protocol called WTLS (Wireless Transport Layer Security) for data security in wireless communication, a process of converting a WAP (Wireless Application Protocol) gateway (SSL) into a secure socket layer (SSL) Data leakage may occur in the Therefore, end-to-end must be unified in one protocol or data should be transmitted and received using PKI (PublicKey Infrastructure) base. In order to use the PKI in the wireless Internet, unlike the wired communication device, the memory capacity of the wireless communication device and the processing power of the central processing unit (CPU) are significantly reduced. Therefore, these factors should be considered.

To this end, when using a Subscriber Identity Module (SIM) or Universal Subscriber Identity Module (USIM) of a Global System for Mobile Communication (GSM) method used in Europe, a smart card type memory and a processor exist. GSM is a digital mobile telephone system widely used in Europe and elsewhere and is a variant of TDMA (Time Division Multiple Access). This is one of the most widely used digital wireless communication technologies with TDMA and Code Division Multiple Access (CDMA). GSM digitizes and compresses the data and sends it along with two other user data over one channel, each with its own unique time zone. GSM can operate in both the 900 MHz and 1800 MHz frequency bands.

However, when using such a method, there exists a problem of validating a user certificate by a PKI. Therefore, in order to solve this problem, a method of issuing a mini-certificate to a server and a WAP gateway has been conventionally used. However, in the wireless Internet, unlike a wired Internet, in consideration of data processing performance and memory capacity of a wireless communication device, a short term certificate is issued, thereby performing electronic commerce without verifying validity.

On the other hand, Korean Patent Publication No. 2001-008042 discloses a system for providing a certification verification agent service using a double digital signature for the verification of the certificate.

Figure 2 shows the overall configuration of a conventional authentication confirmation agent service providing system.

Referring to FIG. 2, in the conventional authentication confirmation service providing system, the terminals 1 and 2 transmit and receive messages in the wireless network 3. The wired / wireless gateway system 4 connects the wireless network 3 and the wired network 5. The certificate issuing system 6 issues a certificate to the terminal user. The certificate directory system 7 is connected to the wired network 5 and publishes the certificate issued by the certificate issuing system 6 so that wired and wireless users can view it. The authentication verification agency system 8 is connected to the wired network 5 to provide a certification verification agency service. The application service system 9 delivers the message sent from the terminal to the receiving side.

However, in the case of using such a certification verification agent system, in order to verify the validity of the certificate, a separate system has to be provided, which requires a lot of additional effort or expense. In addition, there is a difficulty in attaching a separate signature to the certificate list in order to verify the certificate by the authentication verification agent system.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method and system for transmitting a certificate revocation list in real time over wireless communication by using an FM (Frequency Modulation) additional broadcasting capable of real-time data transmission. .

In addition, the present invention is to classify the user by group, and only the user of the group that needs the certificate revocation list can receive the corresponding certificate revocation list, real-time certificate in wireless communication that can increase the efficiency of real-time wireless data transmission It is an object of the present invention to provide a method and system for transmitting abolished lists.

In addition, the present invention provides a real-time certificate verification method and system for storing the certificate revocation list classified by group in the user's wireless communication device, and update the certificate revocation list every time there is a transmission, enabling efficient certificate validation. Its purpose is.

1 illustrates the structure of an X.509 V2 certificate revocation list.

Figure 2 is an overall configuration diagram of a conventional authentication confirmation agency service providing system.

3 is a diagram illustrating a frame hierarchy of a DARC system in a method for transmitting a real-time certificate revocation list in wireless communication according to an exemplary embodiment of the present invention.

4A to 4C show the structure of the data packet layer of such a DARC system.

5 is an overall configuration diagram of a real-time certificate revocation list transmission system according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a part added to an extended field of a certificate revocation list in the real-time certificate revocation list transmission method (DARC-CRL) according to a preferred embodiment of the present invention. FIG.

7 is a diagram illustrating a transmission process between a CRL transmission system and a DARC transmission system in a real-time certificate revocation list transmission method (DARC-CRL) according to a preferred embodiment of the present invention.

8 is a block diagram of a user terminal device capable of receiving a certificate revocation list in real time in the real-time certificate verification system of the present invention.

9 is a diagram showing a symbol for comparing the daily traffic of the certificate revocation list with a conventional transmission method in the real-time certificate revocation list transmission method according to a preferred embodiment of the present invention.

10 is a diagram comparing the transmission time according to the DARC-CRL scheme, conventional CRL scheme, delta-CRL scheme according to an embodiment of the present invention.

(Name of the code for the main part of the drawing)

20: wireless communication device 22: DARC transmission system

24: CRL transmission system 26: certificate issuance system

100: user terminal device 150: memory system

152: flash memory 154: smart card

160: CPU 162: ALU

164: Register 166: Controller

170: DARC receiver 180: input device

190: output device

In order to achieve the above object, the real-time certificate revocation list transmission method of the present invention is a method for transmitting a certificate revocation list to a user's communication device through a wireless transmission system capable of broadcasting, the certificate revocation list is no longer used Generating a certificate revocation list to a wireless transmission system for transmission to a user's communication device, wherein the certificate revocation list includes a wireless transmission field indicating a wireless transmission method and a user group in an extension field. It may include at least one of a designated group field, a frequency field indicating a frequency band, and a CRL classification field.

The wireless transmission scheme may include at least one of DARC, RDS, HSDS, and DAB.

The user group may include at least one of a region, an industry, an interest field, an age, and a gender.

The CRL classification field may include a CRL or a delta-CRL.

Providing the certificate revocation list to the wireless transmission system may use an encryption algorithm.

In addition, the real-time certificate revocation list transmission method of the present invention is a method for transmitting a certificate revocation list to a user's communication device through a wireless transmission system capable of broadcasting, comprising: classifying a user to receive a certificate revocation list by group; Specifying at least one of a group information of a user who will receive the certificate revocation list and a wireless transmission system information to be used in the extended field of the certificate revocation list, checking the occurrence of the certificate revocation list, and generating a certificate revocation list. In this case, the method may include providing the certificate revocation list including the extension field to the wireless transmission system so as to transmit to the communication device of the user.

The real-time certificate revocation list transmission method may further include providing the entire certificate revocation list to the wireless transmission system when the certificate revocation list does not occur for a certain period of time.

The real-time certificate revocation list broadcasting method of the present invention includes receiving a certificate revocation list from a CRL transmission system, and broadcasting the certificate revocation list to be received by a user's communication device. The revocation list may include at least one of a wireless transmission field indicating a wireless transmission scheme, a group field indicating a user group, a frequency field indicating a frequency band, and a CRL classification field in an extension field.

In addition, the real-time certificate verification method of the present invention comprises the steps of receiving a certificate revocation list broadcast from a wireless transmission system, determining a transmission group specified in the extension field of the certificate revocation list, the transmission group is a group of users In the case of, the method may include storing the certificate revocation list in a memory of the wireless communication device, and validating the certificate using the certificate revocation list stored in the memory.

The memory may be a flash memory or a smart card.

In addition, the real-time certificate revocation list transmission system of the present invention in the system for transmitting a certificate revocation list to the user's communication device through a wireless transmission system capable of broadcasting, a certificate revocation list for generating a certificate revocation list that is no longer used And a list generation unit and a certificate revocation list transmission unit for providing the certificate revocation list to the wireless transmission system for transmission to a user's communication device, wherein the certificate revocation list is a wireless transmission field indicating a wireless transmission method in an extension field, a user. It may include at least one of a group field for designating a group, a frequency field indicating a frequency band, and a CRL classification field.

In addition, the real-time certificate revocation list transmission system of the present invention is a system for transmitting a certificate revocation list to a user's communication device through a wireless transmission system capable of broadcasting, a group for classifying users to receive the certificate revocation list by group A control unit, an extended field control unit for designating at least one of a group information of a user who will receive a certificate revocation list and a wireless transmission system information used in the extension field of the certificate revocation list, and a certificate revocation list check for checking the occurrence of the certificate revocation list And a certificate revocation list transmission unit for providing a certificate revocation list including the extension field to the wireless transmission system so as to transmit the certificate revocation list to the user's communication device when the certificate revocation list is generated.

In addition, the real-time certificate revocation list broadcasting system of the present invention includes a receiving unit for receiving a certificate revocation list from the CRL transmission system, and a transmitting unit for broadcasting the certificate revocation list to receive from the user's communication device, the certificate The revocation list may include at least one of a wireless transmission field indicating a wireless transmission scheme, a group field indicating a user group, a frequency field indicating a frequency band, and a CRL classification field in an extension field.

In addition, the certificate verification system of the present invention includes a receiving unit for receiving a certificate revocation list broadcast from a wireless transmission system, a group determination unit for determining a transmission group specified in the extension field of the certificate revocation list, and the transmission group is In the case of a group, the controller may include a controller for storing the certificate revocation list in a memory of the wireless communication device, and a verification unit for validating a certificate using the certificate revocation list stored in the memory.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The real-time certificate verification method of the present invention uses FM additional broadcasting to solve the problem of integrity, which is a problem of certificate revocation list management, and excessive traffic between the server and the network due to the implementation process.

FM additional broadcasting is broadcasting by multiplexing voice or digital data in unused band of 53 ~ 100KHz among bandwidth allocated to one FM broadcasting channel. That is, it is a broadcast that can provide additional services such as program automatic tuning, time information, traffic information, weather information, real-time social information such as stock trends, radio call, emergency alert, traffic data of automatic driving system, etc. to the broadcast receiver. .

The FM supplementary broadcasting has been developed to increase the utilization of the broadcasting network of the intensive structure in areas where transmission of radio waves is difficult due to geographical obstacles such as mountains. FM additional broadcasting typically includes a Radio Data System (RDS), a DAta Radio Channel (DARC), a High Speed Subcarrier Data System (HSDS), and Digital Audio Broadcasting (DAB). RDS is a system commercially available in Europe and most of the United States. The transmission speed is 1.187 Kbps, and there is a disadvantage in that it cannot transmit a large amount of data such as a video. The way to overcome this is DARC and HSDS. Globally, DARC was adopted in 1996 as the global standard ITU-R BS.1194. The DARC has a transmission rate of 16 Kbps and maintains an information transmission rate of 9.78 Kbps without compressing data except for parity for improving transmission error.

This DARC system is based on the seven-layer Open System Interconnection (OSI) reference model. In the hierarchical structure of a DARC system, a physical layer (layer 1) provides a function for controlling physical contact between systems. The frame layer (layer 2) uses physical characteristics to perform error detection and recovery in data transmission. The packet layer (layer 3) provides data exchange between systems. The data group layer (layer 4) provides error detection, recovery and multiplexing for data transmission between end systems. The segment layer (layer 5) performs data control and synchronization. The display layer (layer 6) processes this according to the format of the data. The application layer (layer 7) performs information exchange between application processors.

3 illustrates a frame hierarchy of a DARC system in a method of transmitting a real-time certificate revocation list in wireless communication according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the frame layer provides frame synchronization, data format, protection against error, and scrambling related to data transmission. For this purpose, the data packet occupies 176 bits, the CRC bit has 14 bits, and the parity bit has a size of 82 bits.

4A to 4C show the structure of the data packet layer of such a DARC system.

The data packet layer is composed of data packets and logical channels composed of three different channels. The three channels are distinguished by a service ID and may be classified into a service channel, a short message channel, and a long message channel. At this time, all data packets of each channel have a size of 176 bits. At this time, the data group is composed of one or a plurality of data blocks.

As shown in FIG. 4A, a service channel has a 16-bit prefix corresponding to a header, and includes a service ID, a decoding ID flag, an end flag, an update flag, a data group number, and a data packet number. The data block has a size of 160 bits.

The short message channel shown in FIG. 4B includes a 32-bit header prefix and a 144-bit data block. The header portion includes the service ID, decoding ID flag, End flag, update flag, data group number and data packet number, similarly to the service channel.

The long message channel shown in FIG. 4C consists of an 8-bit header portion and a 168-bit data block. At this time, the header portion includes a service ID, a decoding ID flag, a Start flag, and a sequence counter.

Figure 5 shows the overall configuration of the real-time certificate revocation list transmission system according to a preferred embodiment of the present invention.

Referring to FIG. 5, the real-time certificate revocation list transmission system of the present invention includes a certificate issuance system 26 for issuing a certificate and a certificate revocation list (CRL), a CRL transmission system 24, and a DARC receiver through an FM channel. And a DARC transmission system 22 for transmitting a certificate revocation list (CRL) to the user's wireless communication device 20. The DARC transmission system 22 broadcasts the certificate revocation list CRL from the CRL transmission system 24 to the user's wireless communication device 20 in real time whenever there is a change. To this end, the DARC transmission system 22 broadcasts a certificate revocation list (CRL) on a 76 kHz subcarrier (Subcarrier) using a digitally controlled level controlled minimum shifting keying (LMMSK) scheme. Therefore, the user can attach the DARC receiver not only to the wireless communication device 20 capable of wireless communication, such as PDA (Personal Digital Assistants) and IMT2000 (International Mobile Telecommunication 2000), but also to a computer system such as a PC. It will be possible.

At this time, the user is classified into various groups such as an industry or region, and the user can verify the validity of the certificate in real time by selecting and receiving data corresponding to the group from the broadcast certificate revocation list (CRL). have. That is, the user can be classified into a government agency, a school, a school, or the like according to the work engaged by the user, and can be classified into a manufacturing industry, a fishery, an agriculture, a distribution, or a finance according to the type of business. In addition, it may be possible to classify by region of residence, gender, or age. Thus, by classifying users into various groups and displaying the groups to be received in the sent Certificate Revocation List (CRL), users belong to their own groups. Certificate Revocation Lists (CRLs) can be selected and received.

In addition, the certificate revocation list (CRL) is stored in a memory provided in the user's wireless communication device 20, such as a flash memory or a smart card, and the certificate revocation list is received from the DARC transmission system 22. By updating each time a (CRL) is sent, efficient validation of the certificate is possible.

Therefore, the real-time certificate revocation list transmission method of the present invention is referred to as DARC-CRL method hereinafter.

FIG. 6 illustrates a part added to an extended field of a certificate revocation list in the real-time certificate revocation list transmission method (DARC-CRL) according to a preferred embodiment of the present invention.

Referring to FIG. 6, the method for transmitting a real-time certificate revocation list (DARC-CRL) of the present invention adds a DarcCRLGroup field, a CRLGroupIdentifier field, a FrequencyIdentifier field, and a CRLClassification field to an extension field of a certificate revocation list, respectively. The DarcCRLGroup field is for checking the use of the DARC method and is an option that can be changed according to the configuration of the system. That is, this field may not be selected when the DARC method is not used, and it may be selected when the DARC method is used. On the other hand, when using an FM additional broadcast in addition to the DARC scheme may be added to the field to configure the extended field. The CRLGroupIdentifier field corresponds to a field for group classification of a user, and specifies a group for transmitting a certificate revocation list (CRL). The FrequencyIdentifier field is a part for identifying a frequency band used for DARC transmission. The CRLClassification field is a part for identifying a CRL or a delta-CRL for use. Therefore, the real-time certificate revocation list transmission method (DARC-delta-CRL in this case) may be equally applied even when using the delta-CRL scheme as well as the CRL.

On the other hand, in the process of checking whether there is a certificate revocation list (CRL) in the CRL transmission system and transmitting the certificate revocation list (CRL) to the DARC transmission system, there is a case where it should be transmitted in a secure state. do. Since information may not have to be leaked, such as e-commerce or online banking, for example, it is desirable to transmit a Certificate Revocation List (CRL) using a secure protocol. For example, the security protocol may use Secure Socket Layer (SSL), and may use Hyper Text Transfer Protocol (HTTP) for the transmission of a certificate revocation list (CRL).

7 is a diagram illustrating a transmission process between a CRL transmission system and a DARC transmission system in a real-time certificate revocation list transmission method (DARC-CRL) according to an embodiment of the present invention.

Referring to Figure 7, in the real-time certificate revocation list transmission method (DARC-CRL) of the present invention to see the CRL transmission system as a client, the DARC transmission system as a server and look at the transmission process using the encryption protocol between them as follows. .

First, the CRL transmission system requests a connection to the DARC transmission system as a server from the client's point of view (S10). During the connection request, the CRL transport system will send a Client Hello message. The DARC transmission system receiving the access request transmits a Server Hello message in response and transmits a signal requesting a client certificate together with the server certificate (s12 and s14). The CRL transmission system as a client transmits a client certificate according to a request of the DARC transmission system (s16), and provides a cipher suite together with a session key used for encryption to the DARC transmission system (s18). When the certificate verification process is completed, the CRL transmission system and the DARC transmission system will move to the CRL data transmission step. That is, the DARC transmission system may approve or reject it according to the cipher text provided from the CRL transmission system (s20). At this time, if the ciphertext is normally processed, it will go to the CRL data transmission step, and transmit the certificate revocation list according to the ciphertext agreed upon with each other (s22, s24).

The certificate revocation list (CRL) transmitted through this process is broadcast from the DARC transmission system to the user's wireless communication device. Accordingly, each user will select and receive a certificate revocation list (CRL) corresponding to the group to which the group belongs to among the certificate revocation lists (CRLs) that are broadcast. At this time, the DARC transmission system can broadcast in real time whenever a new certificate revocation list (CRL) occurs. In addition, when a new certificate revocation list (CRL) does not occur for a certain time, a periodic renewal process may be performed by broadcasting the entire certificate revocation list (CRL) at regular time intervals, for example, at every one hour interval.

The certificate revocation list (CRL) broadcast from the DARC transmission system is received by the user's wireless communication device equipped with the DARC receiver. If the received certificate revocation list (CRL) is encrypted, it may be decrypted and stored in an internal memory or a storage device such as a smart card.

8 is a block diagram of a user terminal device capable of receiving a certificate revocation list in real time in the real-time certificate verification system of the present invention.

Referring to FIG. 8, the user terminal device 100 may include a memory system 150, at least one CPU (Central Processing Unit) 160, a DARC receiver 170, and an input device connected to the memory system 150 to perform high-speed operation. 180 and an output device 190.

The CPU 160 includes an Arithmetic Logic Unit (ALU) 162 for performing calculations, a register 164 for temporarily storing data and instructions, and a controller 166 for controlling the operation of the user terminal device 100. It may include. The CPU 160 includes companies such as Digital, Alpha, MIPS Technologies, NEC, IDT, Siemens, etc. MIPS, Intel, Cyrix, AMD, and Nexgen. It can be a processor with a variety of architectures, such as x86 and IBM and Motorola's PowerPC.

Memory system 150 is generally a long-term storage medium, such as flash memory (152), smart card (154) and the configuration and operation of electrically erasable programmable read only memory (EEPROM) cells and electrical, magnetic, optical Or another device for storing data using a storage medium. In the case of a computer system having a DARC receiver, a high speed main memory in the form of a storage medium such as RAM (Random Access Memory) and ROM (Read Only Memory), floppy disk, hard disk, tape, CD-ROM, flash memory, etc. And auxiliary memory in the form of a long-term storage medium.

It will be apparent to those skilled in the art that the memory system 150 may have various forms as a product having various storage capabilities.

The DARC receiving unit 170 is an apparatus for receiving a certificate revocation list (CRL) transmitted from the DARC transmission system. Therefore, if the DARC receiver 170 is provided, the certificate revocation list may be received in real time from the wired terminal device as well as the wireless terminal device.

Also, the input device 180 and the output device 190 may be conventional input devices and output devices. The input device 180 may include a keypad provided in the user terminal device 100, for example, a physical transducer such as a touch screen or a microphone. The output device 190 may include a transducer such as a display and a speaker. In addition, devices such as network interfaces or modems may be used as input and / or output devices.

In the technical field of the present invention, the user terminal device 100 may include an OS and at least one application program. The OS is a set of software that controls the operation of the user terminal device 100 and designation of resources. An application program is a set of software for performing a task requested by a user by using computer resources available through an OS. The OS and applications will reside in memory system 150. In accordance with the experience of those skilled in the art of computer programming, unless otherwise described, the present invention will be described in accordance with representations of operations and operations performed by the user terminal device 100. This operation is computer based and may be performed by the OS or a suitable application. In addition, such operations and functions not only change the operation of the CPU 160 and the operation of the user terminal device 100 for the electrical signals such as data bits causing conversion or interruption of the electrical signals, but also within the memory system 150. Management of the data bit signals stored in the memory area. The memory region in which the data bit signal is managed is a physical region having electrical, magnetic or optical characteristics corresponding to the data bit.

When comparing the transmission rate or transmission time of the certificate revocation list (CRL) using the real-time certificate revocation list transmission method (DARC-CRL) of the present invention with the conventional CRL method or delta-CRL method is as follows. At this time, it is assumed that more than one CA may exist.

To this end, using the symbols shown in Figure 9, let's compare the traffic amount on a daily basis.

9 is a diagram illustrating a symbol for comparing a daily communication amount of a certificate revocation list with a conventional transmission method in a real-time certificate revocation list transmission method according to an exemplary embodiment of the present invention.

In Figure 9, the rate at which the certificate is revoked is calculated as 10%. That is, the total number of certificates is n, the average number of certificates belonging to a CA is k, the percentage of certificates revoked, the number of revoked certificates r, and the number of renewals in a revocation list per day. Let l be the number of bits representing the serial number of the certificate and the number of times a user asks the CA for validity of the certificate per day.

At this time, the number N of data bits to be transmitted to the user for one day in the CA may be expressed by Equation 1 below.

First, let's look at the communication amount required in the conventional CRL method.

If the average number of certificates belonging to a CA is 35 million and the percentage of certificates revoked is 10%, the number of certificates revoked is 3.5 million. If the renewal list is 12 times a day, the certificate revocation list (CRL) is 35 bytes in size, and the number of times a user asks the certification authority (CA) for validity of the certificate is 3.5 million times, 3.5 million × 0.1 × 35 million × 35 bytes = 428.75 Tbytes. With a data rate of 10Mbps per second, the total transfer time is 11,909 hours.

When the certificate revocation list (CRL) is transmitted by the delta-CRL method under the same conditions as the CRL method, 145,833 transmission data are generated per hour among the total transmission amounts, and when this is calculated based on 24 hours, the total transmission amount of 18 Tbytes is generated. . Similarly, when transmitting at a speed of 10 Mbps, the total transfer time is 496 hours.

At this time, the actual transmission speed may be further deteriorated by the load of the network or the load of the system.

On the other hand, since the transmission method using the DARC-CRL method of the present invention is transmitted in real time through the FM channel whenever a certificate is revoked, it is broadcast to 3.5 million users corresponding to the number of certificates revoked by one transmission. The actual transmission amount is 3.5 million × 35 bytes = 122.5 Mbytes. If it transmits at 16Kbps, it can transmit entire data in 2 hours and 13 hours. This is equivalent to generating 145,833 certificate revocation lists (CRLs) per hour, which can be transmitted in 5.4 minutes using the DARC-CRL scheme of the present invention.

10 is a diagram comparing transmission times according to a DARC-CRL scheme, a conventional CRL scheme, and a delta-CRL scheme according to an exemplary embodiment of the present invention.

As shown in FIG. 10, when transmitting the same size certificate revocation list (CRL) under the same conditions, the conventional CRL scheme takes a transmission time close to 12,000 hours, and the delta-CRL scheme close to 500 hours. It takes time. On the other hand, when using the DARC-CRL method of the present invention can be transmitted in two hours, the transmission time can be reduced to the maximum, and the transmission efficiency can also be increased.

In the above description, the DARC scheme has been described as an example of the FM additional broadcasting. However, the present invention is not limited to the DARC scheme, and RDS, HSDS, DAB, or other wireless communication methods can be used as a scheme for transmitting a certificate revocation list. It will be apparent to those skilled in the art having ordinary skill in the art.

As described above, when using the real-time certificate revocation list transmission method (DARC-CRL) of the present invention, since the certificate revocation list (CRL) is stored in the user's communication device, the certificate revocation list (CRL) is downloaded for certificate verification. Verification is possible immediately without waiting for receiving.

In addition, when the certificate revocation list transmission method (DARC-CRL) of the present invention generates a certificate revocation list, it is broadcast to the user in real time, so that the user can verify the validity of the certificate in real time.

In addition, the real-time certificate revocation list transmission method (DARC-CRL) of the present invention classifies users by group using an extended field of the certificate revocation list (CRL), and enables the user to selectively receive them, thereby effectively verifying certificates. This is possible.

In the above described in detail through a preferred embodiment of the real-time certificate verification method and system according to the present invention, the content is not limited to the field of the invention described in the claims below. In addition, in the art, it will be apparent to those skilled in the art that various changes or modifications are made within the scope of the present invention.

Claims (18)

In the method for transmitting a certificate revocation list to the user's communication device through a wireless transmission system capable of broadcasting, Generating a revocation list of certificates which are no longer used among already issued certificates; And Providing the certificate revocation list to a wireless transmission system for transmission to a user's communication device Including, The certificate revocation list above At least one of a radio transmission field indicating a radio transmission scheme, a group field specifying a user group, a frequency field indicating a frequency band, and a CRL distinguishing field in an extension field. Real-time certificate revocation list transmission method comprising a. The method of claim 1, The wireless transmission method At least one of DARC, RDS, HSDS and DAB Real-time certificate revocation list transmission method comprising a. The method of claim 1, The user group is At least one of geography, industry, interests, age and gender Real-time certificate revocation list transmission method comprising a. The method of claim 1, The CRL classification field is How to send a real-time certificate revocation list containing a CRL or delta-CRL. The method of claim 1, Providing the certificate revocation list to the wireless transmission system Real-time certificate revocation list transmission method using encryption algorithm. In the method for transmitting a certificate revocation list to the user's communication device through a wireless transmission system capable of broadcasting, Classifying a user to receive a certificate revocation list by group; Designating at least one of a group information of a user to receive a certificate revocation list and information of a wireless transmission system used in an extended field of the certificate revocation list; Checking the occurrence of the certificate revocation list; And If a certificate revocation list occurs, providing a certificate revocation list including the extension field to the wireless transmission system for transmission to a user's communication device. Real-time certificate revocation list transmission method comprising a. The method of claim 6, If a certificate revocation list does not occur for a period of time, providing a complete certificate revocation list to the wireless transmission system. Real-time certificate revocation list transmission method further comprising a. A method for broadcasting a certificate revocation list to a user's communication device, the method comprising: Receiving a certificate revocation list from a CRL transmission system; And Broadcasting the certificate revocation list to be received by a user's communication device; Including, The certificate revocation list above At least one of a radio transmission field indicating a radio transmission scheme, a group field specifying a user group, a frequency field indicating a frequency band, and a CRL distinguishing field in an extension field. Real-time certificate revocation list broadcasting method comprising a. In the certificate verification method through wireless communication, Receiving a certificate revocation list broadcast from the wireless transmission system; Determining a transmission group specified in an extension field of the certificate revocation list; Storing the certificate revocation list in a memory of a wireless communication device when the transmission group corresponds to a group of users; And Validating a certificate using a certificate revocation list stored in the memory; Real time certificate verification method comprising a. The method of claim 9, The memory is At least one of flash memory, smart card, RAM, ROM, floppy disk, hard disk, tape, and CD-ROM Real time certificate verification method comprising a. In the system for transmitting the certificate revocation list to the user's communication device through a wireless transmission system capable of broadcasting, Certificate revocation list generation unit for generating a certificate revocation list that is no longer used; And Certificate revocation list transmission unit for providing the certificate revocation list to the wireless transmission system for transmission to the user's communication device Including, The certificate revocation list above At least one of a radio transmission field indicating a radio transmission scheme, a group field specifying a user group, a frequency field indicating a frequency band, and a CRL distinguishing field in an extension field. Real time certificate revocation list transmission system comprising a. In the system for transmitting the certificate revocation list to the user's communication device through a wireless transmission system capable of broadcasting, A group control unit classifying users to receive the certificate revocation list by group; An extended field controller for designating at least one of group information of a user to receive a certificate revocation list and information on a wireless transmission system used in an extension field of a certificate revocation list; A certificate revocation list check unit which checks generation of a certificate revocation list; And When a certificate revocation list occurs, a certificate revocation list transmission unit for providing a certificate revocation list including the extension field to the wireless transmission system for transmission to the user's communication device Real time certificate revocation list transmission system comprising a. A system for broadcasting a certificate revocation list to a user's communication device, Receiving unit for receiving a certificate revocation list from the CRL transmission system; And A transmitting unit broadcasting the certificate revocation list so that the user's communication device can receive the certificate revocation list Including, The certificate revocation list above At least one of a radio transmission field indicating a radio transmission scheme, a group field specifying a user group, a frequency field indicating a frequency band, and a CRL distinguishing field in an extension field. Real-time certificate revocation list broadcasting system comprising a. In the certificate verification system through wireless communication, A receiving unit for receiving a certificate revocation list broadcast from a wireless transmission system; A group determining unit that determines a transmission group specified in an extension field of the certificate revocation list; A controller configured to store the certificate revocation list in a memory of a wireless communication device when the transmission group corresponds to a group of a user; And Verification unit for validating the certificate by using the certificate revocation list stored in the memory Real time certificate verification system comprising a. In order to transmit a certificate revocation list to a user's communication device through a broadcast-enabled wireless transmission system, a program of tangible implementations of instructions that can be executed by the digital processing device are implemented, and a record that can be read by the digital processing device. In the medium, The certificate revocation list transmission method, Generating a certificate revocation list that is no longer used; And Providing the certificate revocation list to a wireless transmission system for transmission to a user's communication device Including, The certificate revocation list above At least one of a radio transmission field indicating a radio transmission scheme, a group field specifying a user group, a frequency field indicating a frequency band, and a CRL distinguishing field in an extension field. Computer recording medium comprising a. In order to transmit a certificate revocation list to a user's communication device through a broadcast-enabled wireless transmission system, a program of tangible implementations of instructions that can be executed by the digital processing device are implemented, and a record that can be read by the digital processing device. In the medium, The certificate revocation list transmission method, Classifying a user to receive a certificate revocation list by group; Designating at least one of a group information of a user to receive a certificate revocation list and information of a wireless transmission system used in an extended field of the certificate revocation list; Checking the occurrence of the certificate revocation list; And If a certificate revocation list occurs, providing a certificate revocation list including the extension field to the wireless transmission system for transmission to a user's communication device. Computer recording medium comprising a. In order to broadcast a certificate revocation list to a user's communication device, a program of instructions that can be executed by the digital processing device is tangibly implemented, and in a recording medium that can be read by the digital processing device, The certificate revocation list broadcasting method, Receiving a certificate revocation list from a CRL transmission system; And Broadcasting the certificate revocation list to be received by a user's communication device; Including, The certificate revocation list above At least one of a radio transmission field indicating a radio transmission scheme, a group field specifying a user group, a frequency field indicating a frequency band, and a CRL classification field in an extension field Computer recording medium comprising a. In order to verify the certificate by using the certificate revocation list received through the wireless communication device, a program of instructions that can be executed by the digital processing device is tangibly embodied in a recording medium that can be read by the digital processing device. In The certificate verification method, Receiving a certificate revocation list broadcast from the wireless transmission system; Determining a transmission group specified in an extension field of the certificate revocation list; Storing the certificate revocation list in a memory of a wireless communication device when the transmission group corresponds to a group of users; And Validating a certificate using a certificate revocation list stored in the memory; Computer recording medium comprising a.