KR100742806B1 - Print data communication with data encryption and decryption - Google Patents

Abstract

A print job including print data can be sent to the designated image forming apparatus via the communication medium so that the print data can be printed by the designated image forming apparatus. Encrypting the print data with a designated encryption method in printing a print job, obtaining information about a destination as an image forming apparatus, and obtaining information about the destination obtained by the obtaining means by the disclosed method, apparatus, and medium. Decrypt

Encryption, Private Key, Public Key, Decryption, Print Jobs, Communication

Description

PRINT DATA COMMUNICATION WITH DATA ENCRYPTION AND DECRYPTION}

The present invention relates to a print control apparatus, an image forming apparatus, an image forming apparatus management server, a print processing system, a print control method, a computer program, and a computer readable recording medium, and in particular, data printing through a communication medium such as the Internet and a network. Suitable for

The method of acquiring and printing data from a host computer on a printer (an example of an image forming apparatus) includes a stand-alone connection method in which a host computer and a printer are directly connected to each other through a cable, and a host computer and a printer connected to each other through a network. Network connection methods such that the network connection enables the use of a remote printer.

Among these methods, the network printing method of printing data via a network using the above-described network connection has an advantage of printing on another printer connected to a network (Internet). Network printing has the advantage of being able to print data on a remote computer as described above, as well as allowing a plurality of terminal devices to share a large high speed printer and an expensive color printer. These advantages have greatly facilitated the use of network printing.

However, the network and the Internet are used by an unlimited number of users, and tapping print data running through the network and the Internet as long as the third party intends is not so difficult.

For example, when important data such as security or confidential data is printed on a printer at a client site connected to the Internet, or when such a data is printed by a salesman using a printer near the visited site, the print data is intercepted or sent to the printer. It is not advisable to print on a wrong printer other than the one specified by the printer driver or tampered with before reaching it.

However, according to the prior art, there is a problem that a third party can intercept and use the print data when the data is printed through a communication medium such as a network or the Internet.

The present invention has been developed to solve the above problems. According to the first aspect of the present invention, even when it is intercepted when the print data is printed through a communication medium such as a network, the Internet, it is possible to protect the eavesdropped data from being used by a third party. Further, according to the second aspect of the present invention, even when print data is intercepted and modulated when printed data is printed through a communication medium such as a network or the Internet, the eavesdropping or tampering is detected to protect the data from being illegally printed. Can be.

Further, according to the third aspect of the present invention, when a port, URL, or other information as a suitable example of a destination of a printer is obtained from a printer management server via a network and the Internet, information about the print destination data is protected from eavesdropping. .

Further features and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference numerals are used to designate the same or similar parts throughout the figures thereof.

1 illustrates the concept of a first embodiment of the present invention in connection with an example of the configuration of a print processing system;

2 is a block diagram of a first embodiment of the present invention relating to one example of the configuration of a print processing system;

3A and 3B show a first embodiment using a memory map of RAM;

4 shows a first embodiment of the present invention by explaining an encryption key used in a print processing system;

5 shows a first embodiment of the present invention in relation to a process flow diagram of a printer driver;

6 shows a first embodiment of the invention in relation to a processing flow diagram of a printer;

7 shows a second embodiment of the present invention in relation to a process flow diagram of a printer driver;

8 shows a second embodiment of the present invention in relation to a process flow diagram of a printer;

9 shows a third embodiment of the present invention in relation to a process flow diagram of a printer driver;

10 shows a third embodiment of the present invention in relation to a process flow diagram of a printer;

FIG. 11 is a diagram showing the concept of the fourth embodiment of the present invention relating to one example of the configuration of the print processing system; FIG.

12 is a block diagram of a fourth embodiment of the present invention relating to an example of the configuration of a print processing system;

13A, 13B and 13C show a fourth embodiment using a memory map of RAM;

14 shows a fourth embodiment of the present invention by explaining an encryption key used in a print processing system;

FIG. 15 shows a fourth embodiment of the present invention with respect to the process flow diagram of the printer management server; FIG.

16 shows a fourth embodiment of the present invention with respect to the process flowchart of the printer driver;

17 shows a fourth embodiment of the present invention in relation to a process flow diagram of a printer;

18 shows a fifth embodiment of the present invention with respect to the process flow diagram of the printer management server;

19 shows a sixth embodiment of the present invention with respect to the process flowchart of the printer driver;

20 shows a sixth embodiment of the present invention with respect to the process flowchart of the printer driver;

FIG. 21 shows a sixth embodiment of the present invention with respect to the process flow diagram of the printer management server; FIG.

FIG. 22 shows a sixth embodiment of the present invention with respect to the process flow diagram of the printer;

FIG. 23 illustrates one embodiment of the present invention with respect to an encryption process for information about a destination. FIG.

(First embodiment)

A first embodiment of a print control device, a printer, a printer management server, a print processing system, a print control method, a computer program, and a computer readable recording medium according to the present invention will be described below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing the concept of the first embodiment of the present invention in connection with an example of the configuration of a print processing system.

In an embodiment of the present invention, when a user issues a printing instruction from a host computer 3000 mounted as a print control device, the user may access a network printer 1500a and the Internet 200 which are shared through a network (LAN) 100. It is assumed that data is printed on the Internet printer 1500b connected through the network. Examples of image forming apparatuses other than printers include scanners, fax machines, digital cameras, and multifunction peripherals (multifunctional peripheral devices) having functions such as copiers, printers, fax machines, scanners, and the like.

2 is a block diagram of a first embodiment of the present invention in connection with an example of the configuration of a print processing system.

Unless otherwise specified, host computer 3000 connects to printer 1500 (network printer 1500a and Internet printer 1500b) via a LAN, WAN, public line, Internet, and any other means (communication media). do.

In FIG. 2, the host computer 3000 includes figures, images, characters, tables (including a spreadsheet, etc.) according to a document processing program stored in the program ROM 3b or the external memory 11 of the ROM 3. It includes a CPU 1 for processing the mixed documents, and centrally controls each of the devices 2 to 8 connected to the system bus 4.

The program ROM 3b or the external memory 11 of the ROM 3 stores an operating system program (OS) or the like that is a control program of the CPU 1. The font ROM 3a or the external memory 11 of the ROM 3 stores font data to be used in the above-described document processing. In addition, the data ROM 3c or the external memory 11 of the ROM 3 stores various data for use in performing the above-described document processing.

The RAM 2 functions as a main memory of the CPU 1, a work area, and the like.                 

The keyboard controller (KBC) 5 controls key input from the keyboard 9 or a positioning device (not shown in the accompanying drawings).

The CRT controller (CRTC) 6 controls the display of the CRT display (CRT) 10.

The disk controller (DKC) 7 includes a hard disk (HD) and a floppy disk (storing a boot program, various applications, font data, a user file, an edit file, a printer control command generation program (hereinafter referred to as a printer driver)). Access to external memory 11 such as FD) is controlled.

The printer controller (PRTC) 8 is connected to the printer 1500 via the network 100 and performs a control process for bidirectional communication with the printer 1500. The printer controller 8 may add a command according to the connection protocol to the print job when the print job is sent to the printer 1500. Such instructions may be added automatically by the operating system program (OS).

The CPU 1 performs rasterization on the outline font in the display information RAM in the RAM 2 and enables WYSIWYG on the CRT 10.

The CPU 1 opens various windows recorded in accordance with an instruction indicated by a mouse cursor (not shown in the accompanying drawings) on the CRT 10, and performs various types of data processing. Before performing print processing, the user opens a window for print settings. The user then uses the open window to set up a printing process for the printer driver, such as printer settings, print mode selection, and the like.

In the printer 1500, the printer CPU 12 transmits an image signal as output information according to a control program stored in a program ROM of the ROM 14, a control program stored in an external memory 21, or the like. It has a function to output to the printing unit 17 (printer engine) via the printing unit interface (printing unit I / F) 16 connected to.

The program ROM 14b of the ROM 14 stores a control program and the like of the printer CPU 12. The font ROM 14a of the ROM 14 stores font data and the like for use in generating output information. The data ROM 14a of the ROM 14 stores information for use by the host computer 3000 on a printer which does not have any external memory such as a hard disk.

The printer CPU 12 may communicate with the host computer 3000 via the input unit 18, and may report information in the printer 1500 to the host computer 3000.

Data received from the printer driver is stored in the RAM 13 and converted into image signals by the control program. In addition, the command added according to the communication protocol is interpreted by the control program.

The RAM 13 is a recording medium that functions as a main memory, a work area, or the like of the printer CPU 12, and its memory capacity can be expanded by an optional RAM connected to an expansion port (not shown in the accompanying drawings). The RAM 13 is used as an output information expansion area, an environment data storage area, an NVRAM (nonvolatile RAM), or the like.

The external memory 21 such as the hard disk HD and the IC card described above is accessed-controlled by the memory controller MC 20. The external memory 21 is connected as an optional unit and stores font data, emulation program, form data and the like.

The operation panel 22 is provided with an operation switch, an LED indicator, a liquid crystal panel, and the like. In addition, the above-described external memory 21 is not limited to one unit, but may include at least one memory unit. The memory may also be configured to include, in addition to the built-in font, a plurality of external memory units which store an optional font card and a program for interpreting various types of printer control languages. Furthermore, the memory may include NVRAM (not shown in the accompanying drawings) for storing the printer mode setting information from the operation panel 22.

FIG. 3A illustrates a control program stored in a program ROM 3b of the host computer 3000 according to an embodiment of the present invention and then loaded into the RAM 2 of the host computer 3000 and then executable. Memory map.

Encryption, data characteristic quantity calculation functions, etc. used in the host computer 3000 according to the embodiment of the present invention exist as part of the print process association program 304. The public key of the printer designated to print and the private key of the printer driver itself exist as part of the associated data 303.

3B is a memory showing a control program stored in a program ROM 14b of the printer 1500 and then executable after being loaded into the RAM 13 of the printer 1500 according to an embodiment of the present invention. It's a map.

Decryption, data characteristic quantity calculation functions, etc. used in the printer 1500 according to an embodiment of the present invention exist as part of the print process association program 313. The public key of the particular printer driver and the private key of the printer itself exist as part of the associated data 312.

Figure 4 illustrates an encryption key for use in a print processing system (see the flow charts shown in Figures 5 and subsequent figures) in accordance with an embodiment of the present invention. In this embodiment, encryption is implemented by a public key cryptosystem and a conventional cryptosystem, each information device having its own public key and private key. Therefore, Figure 4 clearly shows each key.

In Fig. 4, the figure showing the key superimposed on the data indicates that the data is encrypted by the corresponding key.

In the print processing system according to the embodiment of the present invention, the printing process cannot be performed on any printer other than the designated printer by sending print data encrypted by the public key cryptographic system.

In public key cryptography systems, encryption and decryption are implemented using different keys (private and public keys) between the user and the user's communication partner, and data encrypted using one key uses the opposite key. It can't be decrypted without it.

In a public key cryptosystem, the public key is usually published and the private key is kept secret. In a public key cryptosystem, there is no need to provide a specific key for each communication partner, and the public key can be published. Therefore, the key can be easily transmitted to a communication partner who is a person who can decrypt the key confined to him.                 

If a public key cryptographic system is applied to, for example, the printer 1500 according to the present embodiment, and the print data is encrypted using the printer's published public key, the print data sent from any printer driver is sent on the destination printer. It can only be printed, preventing other printers from printing that data.

The process of the printer driver for creating an encrypted print job is described in detail below with reference to the process flow shown in FIG.

Upon receiving the print request from the application, the printer driver of the host computer 3000 encrypts the print data using the public key of the destination printer 1500 (step S501).

The encrypted print data is then sent to the printer 1500 as a print job.

The public key of the printer 1500 is published, and the printer driver selects the public key of the destination printer 1500 to be used.

The process of the printer 1500 for acquiring print data from the received print job is described in detail below with reference to the process flow shown in FIG.

The printer 1500 decrypts the print data of the received print job using the private key of the printer 1500 (step S601) and obtains the print data.

As described above, the private key of the printer 1500 is stored by the printer 1500 as an unpublished key.

When an unspecified printer attempts to print the print data, the print data is encrypted, so this print data cannot be decrypted or printed as it is. In addition, since only the designated printer 1500 has a key to decrypt the encrypted data, other printers cannot decrypt the data. Therefore, in the print processing system according to the embodiment of the present invention, even if print data is intercepted on the network 100, it can be protected from printing the print data on another printer.

(2nd Example)

A second embodiment of a print control device, a printer, a printer management server, a print processing system, a print control method, a computer program, and a computer readable recording medium according to the present invention is described below. The hardware configuration of the print processing system according to this embodiment is similar to that of the first embodiment described above. Therefore, the same components as in the case of the first embodiment are assigned the same reference numerals as those shown in Figs. 1 to 6, and detailed description thereof will be omitted here.

In the first embodiment, the print processing system can protect the print data from being printed on another printer even when the print data is intercepted.

However, since the public key of the printer 1500 is published, when someone steals the original print data and sends different data to the printer 1500 according to the same process as the process shown in Fig. 5, the printer 1500 It is not possible to determine whether the print data has been modulated. This can cause serious problems if the print data relates to estimates, securities, and the like.                 

Therefore, in the printing process according to the present embodiment, the presence or absence of the modulation can be checked by the printer by receiving a print job with a digital signature attached to the print data.

A digital signature is obtained by encrypting the characteristic amount calculated for the print data contents using the private key of the printer driver of the host computer 3000. The printer has a built-in public key associated with a particular printer driver, which is used for decryption and digital signature checking.

The characteristic amount of the print data contents is represented by a hash value, a checksum, and the like. The hash value is calculated using a hash function that can hardly be derived from the calculation result, that is, a hash function that is hardly modulated to obtain the same hash value.

The process of the printer driver of the host computer according to the present embodiment for generating an encrypted print job is described in detail below with reference to the process flow shown in FIG.

Upon receiving print data in accordance with a print request from an application, the printer driver of the host computer encrypts the print data using the public key of the destination printer (step S701).

Then, the characteristic amount is calculated from the original unencrypted print data using the characteristic amount calculation function (step S702), and the characteristic amount is encrypted using the private key of the printer driver (step S703). The result is used as a digital signature. The host computer then sends the combination of the encrypted print data and the digital signature to the printer to print the print data as a print job.

The process according to this embodiment of obtaining print data from the received print job is described in detail below with reference to the process flow shown in FIG.

The printer decrypts the print data in the received print job using the printer's private key (step S801) to obtain print data. Then, the printer decrypts the digital signature in the print job using the public key of the source printer driver (step S802) to obtain the characteristic amount of the obtained print data.

Then, the printer calculates the characteristic quantity from the obtained print data using the characteristic quantity calculation function (step S803), compares the characteristic quantity with the characteristic quantity of the received print data (step S804), and the characteristic If the amounts match each other, it is confirmed that the print data obtained in step S801 is not modulated.

If the characteristic amount calculated by the printer in step S804 does not match the characteristic amount of print data received in the process, the following situation can be assumed.

That is, when the print data cannot be decrypted using the public key of a specific printer driver and the source of the received print data is different from the correct host computer, the calculated characteristic amount of the print data is different from that of the received print data. There may be cases where modulation of print data is indicated. In each such case, the print job was not sent correctly.

In the print processing system according to the present embodiment, illegal print data can be detected by the printer. If illegal print data is detected, the illegal print data is not output after the detection, and as an effective measure, it reports to the host computer about the reception of the illegal print data.

In this embodiment, the printer main body has a characteristic quantity calculation function common to the printer driver. In addition, it is assumed that the public key of a specific printer driver (or host computer) is registered in advance in the printer main body.

The encryption key unique to the printer driver is not limited to the printer driver, and may be replaced with an encryption key unique to the host computer 3000 or the current user.

For example, if the encryption key is unique to the host computer 3000, the host computer 3000 is used in the multi-user mode so that all users using the host computer 3000 print data on the printer 1500 under the same conditions. You can print

If the encryption key is unique to a user, the print data can be printed under the same conditions by a desktop PC in the company or an external notebook PC.

Therefore, in any case where the encryption key is unique to the printer driver, host computer 3000, or user, only one public key can be registered with the printer.

(Third Embodiment)

A third embodiment of a print control device, a printer, a printer management server, a print processing system, a print control method, a computer program, and a computer readable recording medium according to the present invention is described below. The configuration of the hardware of the print processing system according to the present embodiment is similar to that of the first and second embodiments described above. Therefore, the same reference numerals as those shown in Figs. 1 to 8 are assigned to the same components as those in the first and second embodiments, and the detailed description thereof is omitted.

In the above-described first and second embodiments, print data is protected from being intercepted or intercepted and tampered with, so that the printer driver can print with improved security for the print data.

However, in the public key cryptography system described above, since encryption and decryption of print data require a long processing time, it is not preferable to apply the method to large-scale print data.

Therefore, this embodiment describes a conventional encryption system (which requires much shorter processing time) with much higher performance than in the case of a public key cryptosystem.

A conventional encryption system is a method of encrypting and decrypting data using the same key (secret key) between a user and its partner. In practice, the data is encrypted by replacing or shifting the bit string of the sentence with another bit string, according to the rules indicated by the secret key.

The processing of a conventional cryptographic system is more complicated than that of a public key cryptographic system, which is characterized by the difficulty of factoring the values obtained by multiplying the decimals or extracting the values from an oval curve into which a value is entered. It is considered a few hundred times faster.

However, on the other hand, it is necessary to deliver the secret key to each partner in a secure manner, and to provide a specific secret key to each partner.                 

In this embodiment, the public key cryptographic system is combined with a conventional encryption system to encrypt print data using a secret key, and the secret key is delivered to the printer using the public key.

The process of the printer driver for generating an encrypted print job is described in detail below with reference to the process flow shown in FIG.

Upon receiving print data in accordance with a print request from an application, the printer driver of the host computer first generates a secret key (step S901), and encrypts the received print data using the generated secret key (step S903). The generated secret key is encrypted using the printer's public key (step S903).

Then, the characteristic amount is calculated from the original unencrypted print data using the characteristic amount calculation function (step S904), and the characteristic amount is encrypted using the private key of the printer driver (step S905). The result is a digital signature.

The host computer then sends a combination of the print data encrypted using the private key, the private key encrypted using the printer's public key, and the digital signature to the printer as a print job.

The process of the printer to obtain print data in the received print job is described in detail below with reference to the process flow shown in FIG.

The printer decrypts the received secret key in the print job using the printer's private key (step S1001) to obtain the secret key in the print job.

Then, the print data in the print job is decrypted using the obtained (decrypted) secret key (step S1002) to obtain print data.

The digital signature of the print job is decrypted using the public key of the source printer driver (step S1003), and the characteristic amount of the print data is obtained.

From the obtained print data, the printer main body calculates the characteristic amount using the characteristic amount calculation function (step S1004), and compares the calculated characteristic amount with the received print data characteristic amount (step S1005). When the characteristic quantities match with each other, it is confirmed that the print data obtained in step S1002 is not modulated.

Therefore, according to this embodiment, the time consuming public key cryptosystem is used only for encrypting and decrypting the secret key, and it is not necessary to manage the secret keys for each of a plurality of printers connected to the network and the Internet. In addition, since the host computer can change the secret key each time communication is established, the print data can be delivered to the printer more securely.

(Example 4)

A fourth embodiment of a print control device, a printer, a printer management server, a print processing system, a print control method, a computer program, and a computer readable recording medium according to the present invention will be described below.

In the first to third embodiments of the present invention described above, by encrypting the print data and allowing only a designated printer to decrypt the data, it is possible to protect the print data from being eavesdropped and to provide digital signature for the print data. In addition, the print data can be protected from tampering (digital signatures are obtained by a print data source that encrypts the characteristic quantity of print data using its own private key, By checking the contents, it is possible to detect whether data has been tampered with).

However, in the method disclosed in the first to third embodiments described above, the host computer (or printer driver) must know the public keys of all the printers that can be specified. Similarly, the public keys of all printer drivers must be recorded in the main body of the printer.

Therefore, large-scale print processing systems that can use a plurality of host computers and printers need to do the hard work of recording and maintaining the necessary information.

In such a situation, the present embodiment maintains to securely transmit print data via the Internet and a network by using the print processing systems disclosed in the first to third embodiments described above, and the printer management server needs to relate to the public key of the printer and the like. The information is centrally managed, and the printer driver obtains necessary information from the printer management server, thereby eliminating the need to manage information about each printer. The print processing system of the above-described configuration will be described below.

Therefore, the hardware configuration of the print processing system according to this embodiment is designed by adding a printer management server to the print processing systems disclosed in the first to third embodiments of the present invention. Therefore, the same reference numerals as in FIGS. 1 to 3 are assigned to the components included in the first to third embodiments, and detailed description thereof will be omitted.

11 shows the concept of the fourth embodiment of the present invention in connection with an example of the configuration of a print processing system.

When a user issues a print instruction from the host computer 3000, a network printer 1500a shared on a network (LAN) 100 and a printer 1500b connected through the Internet 200 perform a printing process.

The printer management server 4000 (4000a, 4000b) manages information (setting position, address, encryption key, etc.) about the printers, and the host computer 3000 needs necessary information about the printer from the printer management server 4000 during printing. Acquire and transmit print data to the corresponding printer.

The print processing system according to the present embodiment may also transmit print data to the printers 4000a and 4000b through the printer management server 4000. The printer management server 4000 may be connected to the network 100 or the Internet 200.

12 is a block diagram showing a fourth embodiment of the present invention in connection with an example of the configuration of a print processing system.

Unless otherwise specified, the host computer 3000 is connected to the printer 1500 via a LAN, WAN, public line, Internet, or the like.

In FIG. 12, the printer management server 4000 includes a CPU 31 that executes a control program stored in a ROM 33 or an external memory (not shown in the accompanying drawings), a main memory of the CPU 31, a work area, and the like. It includes a RAM 32 functioning as a CPU, the CPU 31 controls each unit 32, 33 connected to the system bus 35 in the center.

The network interface card (NIC) 34 performs a bidirectional communication process with the printer driver and the printer 1500.

FIG. 13A illustrates a control program stored in a program ROM 3b of the host computer 3000 and executable after being loaded into the RAM 2 of the host computer 3000 according to an exemplary embodiment of the present invention. Memory map.

The encryption, data characteristic quantity calculation function, and the like used in the host computer 3000 according to the embodiment of the present invention exist as part of the print process association program 304.

The public key of the printer management server 4000 and the private key of the printer driver itself exist as part of the associated data 303.

13B is stored in the program ROM 33 (or an external memory not shown in the accompanying drawings) of the printer management server 4000 according to the embodiment of the present invention, and then the RAM 32 of the printer management server 4000. It is a memory map showing a control program that can be executed after being loaded into.

The encryption / decryption, data characteristic amount calculation function, printer search process, and the like used in the printer management server 4000 according to the embodiment of the present invention exist as part of the print process association program 313.

Printer information (setting position and address of each printer, public key of each printer, etc.) managed by the printer management server 4000 exists as part of the relevant data 312.                 

FIG. 13C is a memory showing a control program stored in a program ROM 14b of the printer 1500 according to an embodiment of the present invention, and executed after being loaded into the RAM 13 of the printer 1500. It's a map.

Decryption, data characteristic amount calculation functions, etc. used in the printer 1500 according to an embodiment of the present invention exist as part of the print process association program 323. The public key of the printer management server 4000 and the private key of the printer driver itself exist as part of the associated data 322.

FIG. 14 illustrates a key used in a print processing system (see the flow charts shown in FIG. 15 and subsequent figures) in accordance with an embodiment of the present invention. In this embodiment, encryption is realized by a public key cryptosystem, where each information device has its own public key and private key. Therefore, each key is displayed individually.

In Fig. 14, the figure showing the key superimposed on the data indicates that the data is encrypted by the corresponding key.

In the print processing system according to the embodiment of the present invention, the printer driver securely obtains information about the printer 1500 from the printer management server 4000, and print data encrypted by the public key cryptographic system is sent to the printer 1500. Is sent.

In public key cryptography systems, encryption and decryption are implemented using different keys (private and public keys) between the user and the user's communication partner, and data encrypted using one key does not use the opposite key. It can't be decrypted without it.                 

In public key cryptosystems, the public key is generally published and the private key is kept secret. In a public key cryptosystem, there is no need to provide a unique key for each communication partner, and a public key can be published. Therefore, the person who can easily send the key to the communication partner and can decrypt the password is limited to the user.

If a public key cryptographic system is applied to, for example, the printer 1500 according to the present embodiment, and the print data is encrypted using the printer's published public key, the print data sent from any printer driver is sent on the destination printer. Only can be printed, and therefore other printers can not be printed.

The digital signature is used as a method for the printer driver to securely obtain printer information from the printer management server 4000.

The digital signature is obtained by encrypting the calculation result of the characteristic quantity of the data content to be transmitted using the source private key. In this embodiment, the printer information is encrypted using the private key of the printer management server 4000.

The printer driver holds the public key of the printer management server 4000, decrypts the digital signature using the public key, compares the decrypted digital signature with the characteristic amount calculated from the separately sent printer information, Check the ID and print data (print job) for tampering successfully.

The characteristic amount may be represented by a hash value, a checksum, or the like. The hash value is calculated using a hash function that can hardly be derived from the calculation result, that is, a hash function that is hardly modulated to obtain the same hash value.                 

When a user performs a print operation in a certain application, the application delivers print data to the printer driver and performs a printing process. The printer driver determines a first printer to output data, and sends printer information search request data to the printer management server 4000 to obtain an address and a key of the printer.

The printer selection criteria in the printer management server 4000 that has received the printer information search request data is

Printing a quote on a nearby printer (e.g., the nearest convenience store) when the user is out,

Printing data on the printer closest to you when you are away from home or office,

Printing data secretly on a client's printer;

In order to determine a printer to print data, the user performs a printer selection operation in advance or interactively.

The process of the printer management server 4000 that retrieves printer information and returns that information to the printer driver is described in detail below.

The printer management server 4000 selects an appropriate printer from the printer information list managed by the server according to the contents of the printer information search request data received from the printer driver (required capability of the printer such as the printer position, color / duplex / staple, etc.). Is selected, and printer information regarding the corresponding printer is retrieved (step S501).                 

The above printer information includes a printer address, a public key, and the like of the printer.

When a printer sends and receives data with a host using a simple object access protocol (SOAP) implemented on HTTP (hyper text transfer protocol), it is effective to encrypt the URL.

Figure 23 illustrates one embodiment of the present invention relating to an encryption process for information of a destination. In FIG. 23 (1), upon recognizing a print command from a user, the host computer 2301 uses the SOAP implemented on HTTP to send the printer 2300 with the device ID and the device function together with the device ID and the device function. (URL in this case) is requested to be sent as printer information. In (2) and (3) of Fig. 23, the printer transmits the printer information including the URL 2305 to the host computer 2301 which sent the request to obtain the printer information. At this time, the URL is encrypted using the host's public key 2302. At the same time as or immediately after encryption, the post method of HTTP corresponding to the URL of the transmitter from the external unit is waited. In (4), the host computer 2301 uses its own private key 2303 to decrypt the URL. Using the HTTP post method, the host computer 2301 inputs data to be printed to a decrypted URL representing a predetermined storage unit in the printer. The post method is defined in HTTP and is a procedure that is called remotely for data entry into a given store. See, for example, RFC 2616, a document issued by the Internet Engineering Task Force (IETF).

At this time, since the printer waits for the external post method in step (2) described above, when the URL is transmitted as raw data, it is not secure and externally vulnerable. In other words, if a URL is sent as raw data, it can be an attack target from malicious crackers. If the malicious cracker is informed of the URL, he may use the obtained URL to take a cracking operation, such as a recording operation, or attempt an illegal access to the storage of the URL in the printer. Therefore, it is preferable that the URL be transmitted after being encrypted in the printer using the public key obtained from the host computer. The host computer decrypts the URL obtained from the printer using its own private key in the host computer, and transmits the print data by the post method of HTTP using the URL.

URL is obviously an example of a unified resource identifier (URI). Although the URL has been disclosed as a preferred example above, it also provides security for identification information indicating a destination printer, such as an IP address, an identifier address of an SMB defined by NETBEUI, etc., namely information on the destination and information on the destination of the image forming data. It is also effective in strengthening.

In printer search step 501, it is not always necessary to select one printer. That is, in the printer search step 501, the printer management server 4000 roughly selects a few printers according to the conditions (contents of the printer information search request data), and printer information about the roughly selected printers is sent to the printer driver. When returned, an interactive process can be performed that allows the printer driver to finally select the desired one of the roughly selected printers.                 

In addition, the printer management server 4000 may transmit the printer information about the entire printer managed by the printer without roughly selecting the printer, and allow the printer driver to select the desired printer.

At this time, the printer management server 4000 calculates the characteristic quantity from the retrieved printer information using the characteristic quantity calculation function (step S502), and encrypts the characteristic quantity using the private key of the printer management server 4000 (step S503). The result obtained in step S503 is a digital signature. Finally, the printer information and the digital signature are returned to the printer driver.

The process of the printer driver for sending an encrypted print job to the printer will be described in detail below with reference to the process flow shown in FIG.

By using the public key of the printer management server 4000, the printer driver decrypts the digital signature included in the printer information and the digital signature returned from the printer management server 4000 and obtains the characteristic amount (step S601). . It is assumed that the printer driver holds the public key of the printer management server 4000.

The printer driver then calculates the characteristic quantity from the obtained printer information using the characteristic quantity calculation function (step S602), compares it with the received characteristic quantity (step S603), and matches the characteristic quantities with each other as a result of the comparison. The printer information has been sent from the preferred printer management server 4000 and that the print data has not been tampered with.

At this time, the printer driver retrieves the public key included in the printer information (step S604), and encrypts the print data sent from the application using the retrieved public key (step S605). Finally, the encrypted print data is sent as a print job for the printer 1500.

The process of the printer for obtaining print data from the print job is described in detail below with reference to the process flow shown in FIG.

The printer 1500 decrypts the print data in the received print job using the private key of the printer 1500 (step S701) to obtain print data.

In each step shown in Figs. 16 and 17, a print job can be sent from the printer driver to the printer 1500, which protects the print job from being illegally printed by a printer other than the designated printer.

As long as the printer driver only knows the secret key of the printer management server 4000, the printer driver can securely obtain printer information without separately managing the address, performance, or secret key of the target printer. That is, the printer management server 4000 only needs to be properly maintained to easily and safely print the print data from any host computer.

(Example 5)

A fifth embodiment of a print control device, a printer, a printer management server, a print processing system, a print control method, a computer program, and a computer readable recording medium according to the present invention will be described below. The hardware configuration of the print processing system according to this embodiment is similar to that of the fourth embodiment described above. Therefore, the same components as those in the fourth embodiment are assigned the same reference numerals as those shown in Figs. 11 to 15, and detailed description thereof will be omitted here.

In the above-described fourth embodiment, since the digital signature is added to the information delivered in response to the printer information acquisition request of the printer driver, the data is unlikely to be tampered with, but can be referenced by anyone via the network. Therefore, subsequent actions can be tracked by that third party.

Therefore, this embodiment shows an example of encrypting the data returned by the printer management server 4000 in order to enhance the security of the information.

The difference from the fourth embodiment is the communication between the printer management server and the printer driver, and the process of printing encrypted print data at the printer side is the same as the process shown in FIG.

When a user performs a print operation in an application, the print data is delivered by the application to a printer driver for a printing process. The printer driver transmits printer information search request data to the printer management server 4000. At this time, according to this embodiment, the public key of the printer driver is also transmitted to reduce the information for server management. If the server manages the public key of the managed printer driver, transmission is unnecessary.

The process of the printer management server 4000 that retrieves printer information and returns it to the printer driver is described in detail below with reference to the process flow shown in FIG.                 

The printer management server 4000 searches for an appropriate printer from the printer information list managed by the server according to the contents of the aforementioned printer information search request data received from the printer driver (step S801). The process of this step is the same as the process in step S501 disclosed above with reference to the fourth embodiment.

The printer management server 4000 then encrypts the retrieved printer information using the received printer driver public key (step S802). Then, the printer management server 4000 calculates the characteristic quantity from the original printer information using the characteristic quantity calculation function (step S803), and encrypts the characteristic quantity using the private key of the printer management server 4000 ( Step S804).

The result obtained in step S804 is a digital signature. Finally, the encrypted printer information and digital signature are returned to the printer driver.

The process of the printer driver for sending an encrypted print job to the printer is described in detail below with reference to the process flow shown in FIG.

The printer driver decrypts the printer information received from the printer management server 4000 using the private key of the printer driver (step S901), and obtains the printer information.

The printer driver decrypts the digital signature received from the printer management server 4000 using the public key of the printer management server 4000, and obtains the characteristic amount of the printer information (step S902). It is assumed that the printer driver holds the public key of the printer management server 4000.                 

Then, the printer driver calculates the characteristic quantity from the obtained printer information using the characteristic quantity calculation function (step S903), compares it with the received characteristic quantity (step S904), and matches the characteristic quantities with each other as a result of the comparison. If it is confirmed that the obtained printer information has been sent from the preferred printer management server 4000 and that the print data has not been tampered with.

Then, the printer driver retrieves the public key included in the printer information (step S905), and encrypts the print data received from the application using the received public key (step S906). Finally, the encrypted print data is sent to the printer 1500 as a print job.

In the above-described steps, the printer information returned from the printer management server 4000 can be accessed only by the printer driver that issues a request to the printer management server 4000, so that security can be strengthened successfully.

Since the printer driver sends its own public key, the printer management server 4000 does not need to manage the corresponding print driver. Since the public key is published, there is no problem in transferring it to the printer management server 4000.

In this embodiment, the printer information is encrypted. However, the means for sending the printer driver's public key from the printer driver to the printer management server 4000 and returning the information encrypted using the public key to the printer driver may also be applied to other data.

Therefore, when data other than the printer information is encrypted, a printer management server 4000 system that does not manage the printer driver may be provided.

In this embodiment described above, the secret key of the printer driver is used. However, the available secret key is not limited to the printer driver's private key, and it is apparent that the key of the host computer 3000 may be used or the key of the current user may be used.

For example, when the secret key of the host computer 3000 is used, the host computer 3000 can be used in the multi-user mode so that anyone on the host computer 3000 can print the print data on the printer 1500 under the same conditions. Can be.

In addition, when the user's private key is used, the user can print the print data under the same conditions by the desktop PC in the company or any notebook PC outside.

(Example 6)

A sixth embodiment of a print control device, a printer, a printer management server, a print processing system, a print control method, a computer program, and a computer readable recording medium according to the present invention will be described below. The hardware configuration of the print processing system according to this embodiment is similar to that of the fourth and fifth embodiments described above. Therefore, the same components as those in the fourth embodiment are assigned the same reference numerals as those shown in Figs. 11 to 19, and the detailed description thereof will be omitted here.

In the fourth and fifth embodiments of the present invention, print data could not be printed on printers other than the designated printer.                 

However, if someone steals the original print data and sends different data to the target printer following the same steps as in the fourth and fifth embodiments, the printer cannot determine whether the received print data has been tampered with.

This problem can be solved by assigning a digital signature to the print data. However, to solve the problem, the public key of the target printer driver must be registered in the printer.

In addition, the public key must be registered with every printer in the print processing system. If a target host computer is added, all printers must be repaired correspondingly. Therefore, determining whether or not the printer driver has been modulated in this way requires labor.

Here, according to the present embodiment, the print data can be transmitted through the printer management server 4000 so that the print data can be protected from being tampered with and the maintenance of the printer 1500 can be almost omitted.

The process of the printer driver for sending print data to the printer management server is described in detail below with reference to the process flow shown in FIG.

When a user performs a print operation in an application, the application delivers print data to the printer driver to perform a print process.

First, in order to determine the destination printer, the printer driver generates request data for the printer management server 4000, or designates the printer through interactive communication with the printer management server 4000 (step S1001), and the printer management server 4000 Create a printer specification request to be sent to).

The printer driver then encrypts the print data received from the application using the public key of the printer management server 4000 (step S1002). Finally, the printer driver sends the encrypted print data and the printer designation request to the printer management server 4000.

The process of the printer management server 4000 for sending an encrypted printer job to the printer 1500 is described in detail below with reference to the process flow shown in FIG.

In response to the printer designation request received from the printer driver, the printer management server 4000 selects an appropriate printer from the printer information list managed by the server, and retrieves corresponding printer information (step S1101). It is assumed that the printer information includes the printer's address, public key, and the like.

Next, the printer management server 4000 decrypts the print data received from the printer driver using the private key of the printer management server 4000 (step S1102), and obtains the print data. After this step, information equipment other than the printer management server 4000 cannot intercept the print data.

Then, the printer management server 4000 encrypts the obtained print data using the public key of the printer included in the printer information (step S1103).

The printer management server 4000 then calculates the characteristic quantity calculation function from the obtained print data (step S1104), and encrypts the calculated characteristic amount using the private key of the printer management server 4000 (step S1105). The result obtained is a digital signature.                 

Finally, the printer management server 4000 transmits the encrypted print data and the digital signature combination as a print job to the printer address included in the printer information.

The process of the printer 1500 for obtaining print data from the received print job is described in detail below with reference to the process flow shown in FIG.

The printer 1500 decrypts the print data included in the received print job using the private key of the printer 1500 (step S1201) and obtains the print data. After this step, information equipment other than the designated printer cannot intercept the print data.

Then, the printer 1500 decrypts the digital signature in the received print job by using the public key of the printer management server 4000 of the source (step S1202), and obtains the characteristic amount of the print data.

The printer 1500 then calculates the characteristic quantity from the obtained print data using the characteristic quantity calculation function (step S1203), compares the result with the received characteristic quantity (step S1204), and the characteristic quantities match each other. If it is confirmed that the print data obtained in step S1201 is not modulated.

Therefore, according to the present embodiment, not only the eavesdropping can be prevented from the print data, but also the modulation can be protected.

In addition, the public key of other information equipment which each information equipment should hold is only the public key of the printer management server 4000 for a printer driver and a printer. The printer management server 4000 only needs to manage the public key of the printer managed by the server. Therefore, even if the configuration of the print processing system is changed, only the printer management server 4000 needs to be repaired.

(Other Embodiments According to the Present Invention)

The present invention enables various devices belonging to a system or devices connected to a computer to operate the various devices to realize the functions of the above-described embodiments, and to a program stored in a computer (CPU or MPU) of the system or device. It also includes an embodiment of providing a program code of the software for operating the various devices accordingly.

In this case, the program code of the above-described software realizes the functions of the above-described embodiments, and the program code itself, a means for providing the program code to a computer, such as a storage medium storing the program code, constitutes the present invention. . Examples of recording media storing such program codes include floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, magnetic tapes, nonvolatile memory cards, ROMs, and the like.

Embodiments of the present invention also include the functions of the above-described embodiments not only when the functions of the above-described embodiments are realized by executing the program code provided by the computer, but also by the OS (operating system) or other application software operating in the computer. Program code in this case is also included.

Furthermore, the provided program code is stored in the memory of the function expansion board of the computer or the function expansion unit connected to the computer, and then some or all of the actual processes are transferred to the program code by the CPU provided to the function expansion board and the function expansion unit. And the functions of the above-described embodiments are realized by such a process. It is obvious that this process is also included in the present invention.

As described above, according to the present invention, a print job including print data is sent to the designated printer through the communication medium, and the designated printer is controlled to print the print data. At this time, the print data is encrypted in an encryption manner in which only a printer designated to print the print job can perform decryption. Therefore, even if a print job including print data is eavesdropped, the print data can be protected from being illegally printed by any other printer and the intercepted print data can be protected from being illegally used by a third party. .

Further, according to another feature of the present embodiment, the feature amount calculated from the print data can be encrypted to generate a digital signature, and the generated digital signature can be included in the print job and transmitted. Therefore, the source of the print job can be specified, and it can be ensured that no modulation has occurred on the print job. As a result, even if print data is printed through the communication medium, it can be detected if tapping and modulation of the print data have occurred. Therefore, erroneous printing can be prevented, and important print data can be printed safely.

According to another feature of the invention, the printers connected to the communication medium can be collectively managed by the printer management server. Therefore, the print control device and the printer only need to hold the public key of the printer management server, and only the printer management server needs to hold the public key of the printer managed by the server. Thus, a plurality of print control devices and a plurality of printers are required. It can greatly reduce the hard work required for maintenance in large systems, including.

Claims (33)

A print control device for transmitting a printing job including print data to a designated image forming apparatus via a communication medium, and controlling the designated image forming apparatus to print the print data. Acquisition means for acquiring information on a destination for a post method from the image forming apparatus, in an encrypted state, wherein the post method is transferred from a remote source to a destination of the image forming apparatus. Remotely called procedure for input of print data-; Decryption means for decrypting the information about the destination acquired by the acquisition means; And Transmission means for transmitting the print data to a destination indicated by the information decrypted by the decryption means by the post method, wherein the transmission is executed according to an HTTP protocol; Print control device comprising a. The method of claim 1, Characteristic amount calculation means for calculating a feature amount from the print data; And And print job sending means for including the feature amount calculated by the feature amount calculating means in the print job and transmitting the feature amount to the designated image forming apparatus via the communication medium. The method of claim 1, And the information on the destination acquired by the acquiring means is a uniform resource identifier (URI). The method of claim 1, Print data encryption means for encrypting the print data by a designated encryption method in printing of the print job, The print data encrypting means functions as a public key encrypting means for performing encryption on the basis of a public key cryptographic system, and uses a public key of the image forming apparatus designated to print the print data based on the public key cryptographic system. A print control device for encrypting the print data. The method of claim 4, wherein Secret key generating means for generating a secret key commonly used by the image forming apparatus designated to print the print data; Secret key encrypting means for encrypting the secret key generated by the secret key generating means; Print job transmission means for including the private key encrypted by the secret key encryption means in the print job and transmitting the key through the communication medium; More, The print data encryption means functions as common key encryption means for performing encryption on the basis of a conventional encryption system, and uses the secret key generated by the secret key generation means on the basis of the conventional encryption system to print the print data. Encrypt, The secret key encrypting means functions as a public key encrypting means for performing encryption based on a public key cryptographic system, performs the encryption based on the public key cryptographic system, and forms the image designated to print the print data. A print control device for encrypting the secret key using a device public key. The method of claim 2, Digital signature generating means for performing digital based encryption on the characteristic quantity calculated by the characteristic quantity calculating means and generating a digital signature by encrypting the characteristic quantity using a private key of the digital signature generating means; Including more, The print job transmitting means includes the digital signature generated by the digital signature generating means in the print job instead of the feature amount calculated by the feature quantity calculating means, and transmits the print job to the communication medium. Printing control unit. The method of claim 4, wherein Image forming apparatus selecting means for selecting an image forming apparatus to print the print data from a group consisting of a plurality of image forming apparatuses by issuing a query to an image forming apparatus management server managing information about the image forming apparatus; And And image forming apparatus information obtaining means for obtaining information about the image forming apparatus specified to print the print data from the image forming apparatus management server. The method of claim 7, wherein The image forming apparatus information obtaining means obtains an address and an encryption key of the image forming apparatus designated to print the print data from the image forming apparatus management server; The print data encrypting means encrypts the print data using the key of the image forming apparatus acquired by the image forming apparatus information obtaining means, and obtains the encrypted print data by the image forming apparatus information obtaining means. A print control device for directly transmitting to the address of the image forming apparatus. The method of claim 7, wherein And the print data encrypting means obtains an encryption key of the image forming apparatus management server, encrypts the print data, and transmits the encrypted print data to the image forming apparatus management server. The method of claim 7, wherein The image forming apparatus information obtaining means sends the image forming apparatus information obtaining means to the image forming apparatus management server the conditions necessary for the image forming apparatus selecting means to select the corresponding image forming apparatus from the group consisting of the plurality of image forming apparatuses. And a device selecting means for selecting a corresponding image forming apparatus from the group consisting of the plurality of image forming apparatuses. The method of claim 7, wherein The image forming apparatus management means by which the image forming apparatus information acquiring means transmits to the server a condition necessary for the image forming apparatus management server to roughly select corresponding image forming apparatuses from the group consisting of the plurality of image forming apparatuses. The image forming apparatus, wherein a server roughly selects the corresponding image forming apparatuses from the group consisting of the plurality of image forming apparatuses, and roughly selected the corresponding image forming apparatuses from the group consisting of the plurality of image forming apparatuses. The management server selects the image forming apparatus to print the print data from the group consisting of the plurality of image forming apparatuses by interactively communicating with the image forming apparatus selecting means. An image forming apparatus for printing encrypted print data included in a print job received through a communication medium, Transmitting means for encrypting and transmitting information on a destination for a post method, the post method being a procedure that is called remotely for input of print data from a remote source to a destination of the image forming apparatus; And Setting means for setting a condition under which the image forming apparatus can receive the post method from a remote source in response to the transmission of the information about the destination; Image forming apparatus comprising a. The method of claim 12, Print data decryption means for decrypting the encrypted print data; Characteristic quantity acquiring means for acquiring a characteristic quantity from a received print job; Characteristic quantity calculation means for calculating a characteristic quantity from the print data decrypted by the print data decryption means; The characteristic quantity calculated by the characteristic quantity calculating means is compared with the characteristic quantity acquired by the characteristic quantity obtaining means, and when the two characteristic quantities coincide with each other as a result of the comparison, the encrypted and received print data is modulated. Print data confirmation means to confirm that it was not An image forming apparatus further comprising. The method of claim 13, Secret key retrieval means for retrieving an encrypted secret key from the received print job; And Decrypt the encrypted secret key retrieved from the secret key retrieving means based on a public key cryptographic system, decrypt the encrypted secret key using the private key of the secret key obtaining means, and print the job Private key acquiring means for acquiring the secret key of More, The print data decryption means functions as a common key decryption means for performing decryption based on a conventional encryption system, applies the conventional encryption system to decrypt the encrypted print data using the secret key, An image forming apparatus for acquiring print data. The method of claim 13, Digital signature retrieval means for retrieving a digital signature from the received print job, The characteristic quantity acquiring means acquires the characteristic quantity by decrypting the digital signature retrieved by the digital signature retrieving means based on a public key decryption method using the public key of the source of the print job, The print data checking means compares the feature amount calculated from the print data decrypted by the print data decryption means with the feature amount acquired by the feature amount obtaining means, and checks whether the feature amounts coincide with each other. And by confirming, the source is a designated image forming apparatus driver and confirms that the encrypted and received print data is not modulated. delete A print control method for transmitting a print job containing print data to a designated image forming apparatus via a communication medium, and controlling the designated image forming apparatus to print the print data. Acquisition step of obtaining information about a destination for a post method from the image forming apparatus in the encrypted state, wherein the post method prints from a remote source to a destination of the image forming apparatus. Remotely called procedure for entering data-; A decrypting step of decrypting the information about the destination acquired in the acquiring step; And A sending step of sending the print data to a destination indicated by the information decrypted in the decrypting step by the post method, wherein the sending is performed according to an HTTP protocol; Print control method comprising a. The method of claim 17, A feature amount calculating step of calculating a feature amount from the print data; And And a print job transmission step of including the characteristic amount calculated in the characteristic amount calculation step in the print job and transmitting the characteristic amount to the designated image forming apparatus through the communication medium. The method of claim 17, And the information on the destination acquired in the acquiring step is a uniform resource identifier (URI). The method of claim 17, A print data encryption step of encrypting the print data by a designated encryption method in printing of the print job, The print data encryption step functions as a public key encryption step of performing encryption based on a public key cryptographic system, and uses a public key of the image forming apparatus designated to print the print data based on the public key cryptographic system. Print control method for encrypting the print data. The method of claim 20, A secret key generation step of generating a secret key commonly used by the image forming apparatus designated to print the print data; A secret key encryption step of encrypting the secret key generated in the secret key generation step; A print job sending step of including the secret key encrypted in the secret key encryption step in the print job and transmitting the key through the communication medium More, The print data encryption step functions as a common key encryption step of performing encryption based on a conventional encryption system, and encrypts the print data using the secret key generated in the secret key generation step based on the conventional encryption system. , The secret key encryption step functions as a public key encryption step of performing encryption based on a public key cryptographic system, performs the encryption based on the public key cryptographic system, and forms the image designated to print the print data A print control method for encrypting the secret key using a device public key. The method of claim 18, A digital signature generation step of generating a digital signature by performing encryption based on the public key cryptosystem on the characteristic quantity calculated in the characteristic quantity calculation step and encrypting the characteristic quantity using a private key of a digital signature generation means; Including, In the print job transmission step, the print control includes the digital signature generated in the digital signature generation step in the print job instead of the feature amount calculated in the feature amount calculation step, and transmits the print job to the communication medium. Way. The method of claim 20, An image forming apparatus selection step of selecting an image forming apparatus to print the print data from a group consisting of a plurality of image forming apparatuses by issuing a query to an image forming apparatus management server managing information about the image forming apparatus; And And an image forming apparatus information obtaining step of obtaining information about the image forming apparatus specified to print the print data from the image forming apparatus management server. The method of claim 23, wherein In the image forming apparatus information acquiring step, an address and an encryption key of the image forming apparatus designated to print the print data are acquired from the image forming apparatus management server; In the print data encrypting step, the print data is encrypted using the key of the image forming apparatus acquired in the image forming apparatus information obtaining step, and the encrypted print data is obtained in the image forming apparatus information obtaining step. A print control method for directly transmitting to the address of the image forming apparatus. The method of claim 23, wherein In the print data encryption step, obtaining an encryption key of the image forming apparatus management server, encrypting the print data, and transmitting the encrypted print data to the image forming apparatus management server. The method of claim 23, wherein The image forming apparatus by transmitting conditions necessary for selecting a corresponding image forming apparatus from the group consisting of the plurality of image forming apparatuses in the image forming apparatus selecting step to the image forming apparatus management server in the image forming apparatus information obtaining step. And a corresponding image forming apparatus is selected from the group consisting of the plurality of image forming apparatuses in the apparatus selecting step. The method of claim 23, wherein The image forming apparatus management server by transmitting a condition necessary for the image forming apparatus management server to roughly select corresponding image forming apparatuses from the group consisting of the plurality of image forming apparatuses to the server in an image forming apparatus information obtaining step; The image forming apparatus management to roughly select the corresponding image forming apparatuses from the group consisting of the plurality of image forming apparatuses and to roughly select the corresponding image forming apparatuses from the group consisting of the plurality of image forming apparatuses. And the server selects the image forming apparatus to print the print data from a group consisting of the plurality of image forming apparatuses by interactively communicating with an image forming apparatus selecting means. An image forming method for printing encrypted print data included in a print job received through a communication medium, A transmission step of encrypting and transmitting information about a destination for a post method, wherein the post method is a procedure called remotely for input of print data from a remote source to a destination of the image forming apparatus; And A setting step of setting a condition under which the image forming apparatus can receive the post method from a remote source in response to the transmission of the information about the destination. Image forming method comprising a. The method of claim 28, A print data decryption step of decrypting the encrypted print data; A characteristic amount acquiring step of acquiring a characteristic amount from the received print job; A characteristic amount calculation step of calculating a characteristic amount from the print data decrypted in the print data decryption step; The characteristic quantity calculated in the characteristic quantity calculating step is compared with the characteristic quantity acquired in the characteristic quantity acquiring step, and when the two characteristic quantities coincide with each other as a result of the comparison, the encrypted received print data is not modulated. Print data confirmation step to confirm that An image forming method further comprising. The method of claim 29, A secret key retrieval step of retrieving an encrypted secret key from the received print job; And Decrypts the encrypted private key retrieved in the secret key retrieval step based on a public key cryptosystem, decrypts the encrypted private key using a private key of a secret key obtaining means, and prints the print job Secret key acquisition step of acquiring the secret key of More, The print data decryption step functions as a common key decryption step of performing decryption based on a conventional encryption system, applying the conventional encryption system to decrypt the encrypted print data using the secret key, An image forming method for acquiring print data. The method of claim 29, A digital signature retrieval step of retrieving a digital signature from the received print job, In the characteristic quantity acquiring step, based on the public key decryption method using the public key of the source of the print job, the characteristic quantity is acquired by decrypting the digital signature retrieved in the digital signature retrieval step, In the print data confirming step, the feature amount calculated from the print data decrypted by the print data decryption means is compared with the feature amount acquired in the feature amount acquisition step, and check whether the feature amounts coincide with each other. Whereby the source is a designated image forming apparatus driver, wherein the encrypted and received print data is confirmed to be unmodulated. Storing a program for sending a print job containing print data to a designated image forming apparatus via a communication medium, and causing a computer to execute a print control method for controlling the designated image forming apparatus to print the print data. A computer readable recording medium, The print control method, Acquisition step of obtaining information about a destination for a post method from the image forming apparatus in the encrypted state, wherein the post method prints from a remote source to a destination of the image forming apparatus. Remotely called procedure for entering data-; A decrypting step of decrypting the information about the destination acquired in the acquiring step; And A sending step of sending the print data to a destination indicated by the information decrypted in the decrypting step by the post method, wherein the sending is performed according to an HTTP protocol; Computer-readable recording medium comprising a. delete

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