JP2009217390A - Printing system, printer, server, client, computer program, and print method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the fact of the alteration even when print data are altered and restored while the print data are stored in a print system. <P>SOLUTION: A client 102 generates print data, and a server 104 stores the print data. In this case, the server 104 (or the client 102) calculates the hash value (first hash value) of the print data, and a printer 106 stores the first hash value. Afterwards, when user authentication is performed, the printer 106 acquires the print data of the user from the server 104, and calculates the hash value (second hash value) of the print data, and compares the second hash value with the stored first hash value. As a result, when the matching result is obtained, it means that the print data have not been altered, and the printer 106 prints out the print data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention generally relates to a printing system, a printer, a server, a client, a computer program, and a printing method suitable for authenticated printing, and more particularly to a technique for confirming whether print data has been falsified.

  In a printing system in which print data is transferred through a network, a method of encrypting data between a host computer and a printer is known as a defense against theft of print data (for example, Patent Document 1). However, in this method, it is necessary to decrypt the data received on the printer side, and depending on the size of the print data, a very high processing capacity is required for the decryption in a short time. Accordingly, the first print may be delayed.

  In order to be able to perform the first print quickly and prevent falsification of the data, the print data is divided into small data fragments (chunks), a hash value for each chunk is calculated, and the hash value of each chunk is calculated. A method is also known in which a unit of transmission data is added to a predetermined chunk different from that, and the unit of transmission data is transmitted to a network printer (for example, Patent Document 2).

  By the way, a printing system is known in which print data output from a client is temporarily stored in the system and then printed in response to a predetermined event. A typical example is an authentication printing (or confidential printing) system (for example, Patent Documents 3 and 4). The authenticated printing system prints out the stored print job of the user only after the authentication as the event is performed.

  In this type of printing system, the risk of falsification of the print data is higher when it is stored in the system than when it is transferred on the network in which Patent Documents 1 and 2 are problematic.

JP 2004-86894 A (abstract) JP 2006-11857 A (Abstract) JP 2002-370407 A (Abstract) Japanese Patent No. 3054230 (FIG. 1)

  In a printing system where there is a risk that the print data may be falsified while being stored in the system as described above, the print data disclosed in Patent Document 2 is divided into a plurality of chunks, and those chunks are divided. Even the method of adding a hash to a file cannot be said to be sufficiently secure. Because while they are stored in the system, they steal those chunks, restore the original print data from those chunks, tamper the print data and split it back into multiple chunks, and hash those chunks This is because the fact of falsification can be concealed by recalculating and adding it to other predetermined chunks, and saving these new chunks with the new hash in the system again.

  Accordingly, an object of the present invention is to make it possible to detect the fact of falsification even if the print data is falsified and re-saved while being saved in the printing system.

  The printing system according to the first aspect of the present invention includes a print data storage unit that stores print data, a first hash value calculation unit that calculates a first hash value of the print data, and the first hash value. A first hash value storage unit that stores the print data separately from the print data; and a second hash value stored in the print data storage unit at a later time than when the first hash value is calculated. A second hash value calculating means for calculating a hash value; a comparing means for comparing the second hash value with the first hash value stored in the first hash value storing means; and the print data. And a print output means for printing out.

  In this printing system, a hash value (first hash value) of print data to be stored is calculated, and thereafter, the first hash value is stored separately from the print data. At any later time (typically, when it is desired to check whether the print data has been tampered with), the hash value (second hash value) of the stored print data is calculated again, and the second The hash value is compared with the first hash value previously calculated and stored. As a result, it can be checked whether the print data has not been tampered with during storage. Since the first hash value is separated from the print data and stored, even if the stored print data is falsified, the first hash value cannot be falsified by itself. Therefore, it is difficult to hide the fact of falsification of print data. The process of calculating and checking the hash value can be performed faster than the process of decrypting the encrypted print data.

  Here, the calculation of the first and second hash values may be performed for the entire print data, or may be performed for each of a plurality of partial data obtained by dividing the print data. In any case, the hash value is stored separately from the print data.

  In a preferred embodiment of the printing system of the present invention, when the print data is written to the print data storage unit, the first hash value calculation unit calculates the first hash value, and the print output When the means tries to print out the print data stored in the print data storage means, the second hash value calculation means calculates the second hash value.

  Accordingly, the first hash value is calculated when the print data is stored, and is stored thereafter. Thereafter, when the print data is to be printed out, the second hash value is calculated. By comparing the first and second hash values, it is possible to check whether or not falsification has occurred during the entire period in which the print data is stored.

  In a preferred embodiment, the printing system has a plurality of machines, one machine has the print data storage unit, and another machine has the first hash value storage unit. Accordingly, the print data and the first hash value are stored in different machines. Even if the print data stored in the first machine is falsified, the first hash value is stored in the second machine and is not falsified, so the fact of falsification cannot be concealed. The reliability of checking whether or not the print data has been falsified is high.

  In a more specific embodiment, the printing system includes a server that is communicably connected to a client that outputs the print data, and a printer that is communicably connected to the server as the plurality of machines.

  And the server stores the print data storage unit that stores the print data received from the client, the first hash value calculation unit that calculates a first hash value of the print data received from the client, A first hash value transmission unit that transmits the first hash value calculated by the first hash value calculation unit to the printer; and a print data transmission that transmits the print data in the print data storage unit to the printer. Means.

  The printer receives the first hash value from the first hash value transmission unit of the server, and the first hash value reception unit of the server receives the first hash value transmission unit. The first hash value storing means for storing one hash value, and the print data in the print data storing means is transmitted to the print data of the server at a later time than when the first hash value is calculated. Print data receiving means received from the means; the second hash value calculating means for calculating the second hash value of the print data received from the print data transmitting means of the server; the comparing means; And print output means for printing out the print data received from the print data transmission means of the server.

  Accordingly, the print data is stored in the server, and the first hash value is calculated. The first hash value is separated from the print data, sent to the printer, and stored in the printer. The printer receives print data from the server, calculates a second hash value for the received print data, and compares the second hash value with the stored first hash value. Even if the print data is falsified while it is stored in the server, the first hash value is stored in the printer and is not falsified, so the fact of falsification cannot be hidden. It is possible to check whether or not falsification has occurred in the route from the server to the printer. For example, in an authenticated printing system in which print data is stored in the server and the print data is transferred from the server to the printer after authentication is performed, the print data while being stored in the server is falsified. Can check.

  In the above-described embodiment, preferably, the server further includes first hash value storage means for storing the first hash value calculated by the first hash value calculation means, and the printer is configured at a predetermined timing. The apparatus may further comprise first hash value search means for searching for the first hash value from the first hash value storage means in the server and writing the first hash value in the first hash value storage means in the printer.

  According to this configuration, when the first hash value is transmitted from the server to the printer, the printer cannot receive the first hash value due to, for example, a power failure or a failure. The hash value of 1 may not be stored. Even in this case, the printer actively searches the first hash value stored in the server at a predetermined timing, so that it is guaranteed that the print data can be tampered with.

  In another more specific embodiment, the printing system includes a client that outputs the print data, a server that is communicably connected to the client, and a printer that is communicably connected to the client and the server. Are provided as the plurality of machines.

  The client calculates the first hash value calculating means for calculating the first hash value of the print data to be output, and the first hash value calculated by the first hash value calculating means. First hash value transmitting means for transmitting a value to the printer.

  Further, the server includes the print data storage unit that stores the print data received from the client, and the print data transmission unit that transmits the print data in the print data storage unit to the printer.

  The printer receives the first hash value from the first hash value transmission unit of the client, and the first hash value reception unit of the client receives the first hash value transmission unit. A first hash value storage unit that stores one hash value; and print data reception that receives the print data from the print data transmission unit of the server at a later time than when the first hash value is calculated. Means; the second hash value calculating means for calculating the second hash value of the print data received from the print data transmitting means of the server; the comparing means; and the print data transmitting means of the server. And print output means for printing out the print data received from the printer.

  Therefore, the client that outputs the print data calculates the first hash value and sends it to the printer, and the printer stores the first hash value. Print data from the client is stored in the server. The presence or absence of falsification of print data in the route from the client to the printer via the server can be checked.

  In this embodiment, it is preferable that the client further includes first hash value storage means for storing the first hash value calculated by the first hash value calculation means, and the printer is configured at a predetermined timing. The apparatus may further comprise first hash value search means for searching for the first hash value from the first hash value storage means in the client and writing the first hash value in the first hash value storage means in the printer.

  According to this configuration, when the first hash value is transmitted from the client to the printer, the printer cannot receive the first hash value due to, for example, a power failure or a failure. The hash value of 1 may not be stored. Even in such a case, the printer actively searches for the first hash value stored in the client at a predetermined timing, so that it is ensured that the falsification check of the print data is possible.

  In any of the embodiments including the printer as described above, preferably, the first hash value transmission unit determines whether a data format of the print data is compatible with a model of the printer, and If the determination result is negative, the transmission of the first hash value of the print data to the printer may be omitted.

  According to this configuration, the data format of the print data that can be understood by the printer differs depending on the printer model. For printers of a model that cannot understand a certain type of print data, useless transmission of the first hash value of the print data is omitted, and network traffic is saved.

  A printer according to another aspect of the present invention includes a first hash value receiving unit that receives a first hash value of print data from an external machine, and a first hash value that is received from the external machine. A hash value storing unit; a print data receiving unit that receives the print data from the external machine or another external machine after the first hash value is calculated; and the external machine or the other The second hash value calculating means for calculating a second hash value of the print data received from an external machine, the second hash value calculated by the second hash value calculating means, and the first hash A comparison unit that compares the first hash value in the value storage unit, and the print data received from the external machine or the other external machine is printed out. And a printing output unit.

  According to this printer, the presence or absence of falsification of print data received from the outside, the first hash value of the print data received prior to the time when the print data was received, It can be checked from the comparison result with the first hash value. Even if the print data is tampered outside the printer between the time when the first hash value is calculated and the time when the print data is received by the printer, the first hash value is stored in the printer. The first hash value is not tampered with, so the fact of tampering is not hidden.

  A server according to another aspect of the present invention is communicably connected to a client that outputs print data, and is communicably connected to a printer that prints out the print data. The server includes a print data storage unit that receives and stores print data from the client, a first hash value calculation unit that calculates a first hash value of the print data received from the client. A first hash value transmitting means for separating the first hash value from the print data and transmitting the first hash value to the printer; and after the calculation of the first hash value, the print data storage means in the print data storage means Print data transmission means for transmitting print data to the printer.

  According to this server, the print data received from the client is stored, the first hash value of the print data is calculated and transmitted to the printer, and after the time when the first hash value is calculated, Send the saved print data to the printer. Therefore, the printer can check whether the print data has been falsified while the first hash value is calculated and stored in the server using the first hash value received from the server. If the print data is falsified while it is stored in the server, the fact that the falsification has occurred is not concealed because the first hash value transmitted and stored in the printer cannot be falsified.

  The present invention also provides a machine-readable computer program for causing a computer to function as the server.

  A client according to still another aspect of the present invention is communicably connected to a server that stores print data, and is communicably connected to a printer that receives the print data stored in the server and prints it out. The client includes a first hash value calculation unit that calculates a first hash value of print data, a first hash value transmission unit that transmits the first hash value to the printer, and the print data to the server. Printing data transmission means for transmitting.

  Accordingly, the print data output from the client is stored in the server, and the first hash value of the print data is stored in the printer. Even if the print data stored in the server is falsified, the first hash value in the printer will not be falsified. When the printer receives print data from the server, the printer can check whether or not the print data has been tampered with using the stored first hash value.

  The present invention also provides a machine-readable computer program for causing a computer to function as the client.

  The present invention further provides a printing method executed by the printing system described above.

  According to the present invention, even if print data is falsified and saved again while being saved in the printing system, the fact of the falsification can be detected.

  Hereinafter, two types of embodiments of a printing system according to the present invention will be described with reference to the drawings. These embodiments are examples in which the present invention is applied to an authentication printing system, but the present invention can also be applied to printing systems other than the authentication printing system.

  FIG. 1 is a diagram showing a configuration of an authentication printing system according to the first embodiment of the present invention.

  As shown in FIG. 1, the authentication printing system 100 can communicate with a client 102 configured by, for example, a personal computer, a server 104 configured by, for example, a personal computer connected to the client 102, and the server 104. A printer 106 connected to the printer. The printer 106 includes an authentication device 108 for user authentication (which may be external or internal, or may not be directly connected to the printer 106, for example, provided in the client 102 or the server 104. Also good).

  The authentication printing system 100 includes an authentication print job (a print job that is printed for the first time after authentication) and a normal print job (not related to authentication, and can be printed immediately after being output from the client 102. Both jobs can be handled. The control based on the principle of the present invention can be applied to both the authentication print job and the normal print job. However, in this specification, normal print job processing will not be described, and only authentication print job processing will be described. The term “print job” is simply used to refer to an authentication print job.

  An outline of functions and operations of the authentication printing system 100 is as follows.

  (1) When the server 104 receives print data of a certain user 110 from the client 102, the server 104 stores the print data in the server 104 until the print output of the print data is completed by the printer 106. When the storage of the print data is started, the server 104 calculates a hash value of the print data (hereinafter referred to as “first hash value”), and transmits the first hash value to the printer 106. The printer 106 stores the received first hash value.

  (2) Thereafter, when the authentication of the user 110 is performed, the printer 106 receives the print data of the user 110 from the server 104, and the received print data hash value (hereinafter referred to as “second hash value”). And the second hash value is compared with the stored first hash value. If the two hash values match as a result of the comparison, it means that the print data has not been tampered with during storage, and the printer 106 prints out the print data.

  Hereinafter, the functional configuration of the authentication printing system 100 will be described in detail with reference to FIG. Note that various functions of the client 102 and the server 104 are typically realized by computer programs executed on computers used as the client 102 and the server 104.

  As shown in the configuration diagram of the authentication printing system 100 in FIG. 1, the client 102 includes an authentication print job generation unit 112 and an authentication print job transmission unit 114. The authentication print job generation unit 112 generates an authentication print job. The authentication print job transmission unit 114 transmits the authentication print job generated by the authentication print job generation unit 112 to the server 104.

  The server 104 includes an authentication print job storage unit 120, a first hash value calculation unit 122, a hash value transmission unit 124, a first hash value storage unit 126, an authentication print job request reception unit 130, an authentication print job search unit 132, and an authentication A print job transmission unit 134 is provided.

  The authenticated print job storage unit 120 temporarily stores the authenticated print job transmitted from the client 102 (until printing by the authenticated print job is completed).

  The first hash value calculation unit 122 prints the print data when the print data of each print job is stored in the authenticated print job storage unit 120 (or when the print data of each print job is received by the server 104). Is calculated (first hash value). Here, one first hash value may be calculated for the entire print data of one print job, or the print data is divided into a plurality of pieces of partial data, one for each piece of partial data. A first hash value (a plurality of first hash values for the entire print data) may be calculated.

  The hash value transmission unit 124 transmits the first hash value calculated by the first hash value calculation unit 122 to the hash value reception unit 136 of the printer 106. However, it is not necessary to send the first hash value of all the print data in the authenticated print job storage unit 120 to the printer 106, and print data suitable for the model of the printer 106 (that is, print data that can be handled by the printer 106). Only the first hash value may be sent to the printer 106.

  The first hash value storage unit 126 stores the first hash value calculated by the first hash value calculation unit 122. What should be noted here is that the first hash value is stored by the first hash value storage unit 126 separately from the print data in the authentication print job storage unit 120. Therefore, the authentication print job Even if the print data in the storage unit 120 is falsified, the first hash value in the first hash value storage unit 126 is not falsified by that alone.

  The authenticated print job request receiving unit 130 receives an authenticated print job request including a user identifier from the printer 142. The authentication print job search unit 132 searches the authentication print job storage unit 120 for an authentication print job having a user identifier corresponding to the user identifier included in the authentication print job received by the authentication print job request reception unit 130. . The authentication print job transmission unit 134 transmits the authentication print job searched by the authentication print job search unit 132 to the printer 106.

  The printer 106 includes a hash value reception unit 136, a first hash value storage unit 138, a hash value search unit 139, an authentication information reception unit 140, an authentication print job request unit 142, an authentication print job reception unit 143, and a second hash value calculation unit. 144, a hash value comparison unit 145, and a print output unit 146.

  The hash value reception unit 136 receives the first hash value transmitted from the hash value transmission unit 124 of the server 104. The first hash value storage unit 138 stores the first hash value received from the server 104 until printing with the print data is completed. What should be noted here is that the first hash value is stored in the printer 106 separately from the print data in the server 104. Therefore, even if the print data in the server 104 is tampered with. By itself, the first hash value in the printer 106 is not falsified.

  The hash value search unit 139 prints from the first hash value storage unit 126 of the server 104 in a language suitable for the model of the printer 106 at the time of startup of the printer 106, error recovery, or other predetermined timing. A first hash value for data (that is, print data of a print job that can be handled by the printer 106) is retrieved, and the retrieved first hash value is stored in the first hash value storage unit 138 (not shown). In the server 104, there is an association between each first hash in the first hash value storage unit 126 and the model information of the printer 106 that matches the original print data, and this association is used in this search. .) The reason for performing this search is that if there is a first hash value transmitted from the server 104 to the printer 106 while the printer 106 is powered off or in an error state, the printer 106 fails to receive it. This is because the first hash value that has been missed is received from the server 104 again.

  The authentication information receiving unit 140 receives authentication information including a user identifier from the authentication device 108. The authentication print job request unit 142 performs user authentication based on the authentication information including the user identifier transmitted from the authentication device 108. If the authentication is successful, the authentication print job request unit 142 generates an authentication print job request including the user identifier. To the authentication print job request receiving unit 130 of the server 104.

  When the authenticated print job transmitting unit 134 of the server 106 returns an authenticated print job in response to the authenticated print job request transmitted from the printer 106 to the server 104, the authenticated print job receiving unit 143 receives the transmitted authentication. Receive a print job.

  When the authenticated print job receiving unit 143 receives an authenticated print job from the server 104, the second hash value calculating unit 144 calculates a hash value (second hash value) of print data of the received authenticated print job. . The hash value comparison unit 145 searches for the same hash value as the calculated second hash value from the first hash values of various authentication print jobs stored in the first hash value storage unit 138. If the first hash value that matches the second hash value is found, this means that the print data of the print job received from the server 1-4 has not been tampered with, and the print data is printed. It passes to the output unit 146. On the other hand, if the first hash value that matches the second hash value is not found, this means that the print data received from the server 104 has been falsified, and the print data is sent to the print output unit 146. Do not pass (or notify the user of any warning even if it is passed to the print output unit 146). The print output unit 146 receives the print data transmitted from the hash value comparison unit 145 and executes print output processing.

  The authentication device 108 includes an authentication information input unit 150 and an authentication information transmission unit 152. The authentication information input unit 150 inputs authentication information including a user identifier from the user 110. The authentication information transmission unit 152 transmits the authentication information received from the authentication information input unit 150 to the authentication information reception unit 140 of the printer 106.

  Next, the operation of the authentication printing system 100 shown in FIG. 1 will be described with reference to a flowchart. FIG. 2 is a flowchart showing an operation flow of the authentication printing system 100 shown in FIG. Therefore, the operation flow of the authentication printing system 100 will be described according to the flowchart of FIG. 2 with reference to FIG.

  First, when the authentication print job generation unit 112 of the client 102 generates a certain authentication print job (step S1), the generated print data of the authentication print job is sent from the authentication print job transmission unit 114 of the client 102 to the authentication of the server 104. It is transmitted to the print job storage unit 120 (step S2). The print data is temporarily stored in the authentication print job storage unit 120 of the server 104 (step S3).

  In the authenticated print job storage unit 120, for example, as shown in FIG. 4, each print data is stored in association with a user identifier indicating each user. When an authentication print job request including a certain user identifier is subsequently received from the printer 106, the print data associated with the user identifier (for example, if the user identifier 00987 in FIG. 4 is designated, the print data Document.prn Aaaaa.prn) is read from the authentication print job storage unit 120 and transmitted to the printer 106.

  Referring again to FIG. 2, based on the print data stored in the authentication print job storage unit 120, the first hash value calculation unit 12 calculates the first hash value of the print data (step S4), and The calculated first hash value is stored in the first hash value storage unit 126 (step S5). Further, the first hash value calculated by the first hash value calculation unit 12 is transmitted to the printer 106 (step S6), received by the hash value reception unit 136 of the printer 106, and stored in the first hash value storage unit 138. (Step S7).

  Next, when the user 110 performs an authentication operation by inputting his / her user identifier to the authentication information input unit 150 of the authentication device 108 (step S8), an authentication print job request including the user identifier is sent to the printer 106. The authentication print job request unit 142 transmits the request to the authentication print job request reception unit 142 of the server 104 (step S9).

  Then, the authentication print job search unit 132 of the server 104 searches the print data associated with the user identifier from the authentication print job storage unit 120 (step S10), and transmits the found print data to the printer 106 (step S11). ).

  Then, the second hash value calculation unit 144 of the printer 106 calculates the second hash value of the print data based on the print data received from the server 104 (step S12). Further, the hash value comparison unit 145 of the printer 106 includes the first hash value of various print data stored in the first hash value storage unit 138 in advance and the same as the second hash value calculated now. It is checked whether there is a thing (step S13).

  FIG. 5 shows various authentication print jobs stored in the first hash value storage unit 138 of the printer 106 (that is, among the authentication print jobs stored in the server 104, jobs suitable for the model of the printer 106). It is a figure which shows the hash value of. A list that matches the second hash value is searched from the list of first hash values as shown in FIG.

  Referring to FIG. 2 again, if the first hash value matching the second hash value is found by the search of hash value comparison unit 145 in step S13, it is determined that the print data has not been tampered with, The print data is transmitted to the print output unit 146. Then, the print output unit 146 receives the print data transmitted from the hash value comparison unit 145 and performs print output (step S14).

  When the print output is completed, a print completion notification is transmitted from the printer 106 to the server 104 (step S15). Then, the server 104 deletes the corresponding print data from the authenticated print job storage unit 120 (step S16), and further, the corresponding hash value from the first hash value storage unit 126 (the first hash value found in step S13). ) Is deleted (step S17).

  Since the server 104 may perform regular modification (setting change or the like) of the hash value, the server 104 recalculates the hash value and transmits it to the printer 106 when the print data is changed. It is desirable to have a mechanism.

  According to the authentication printing system 100 of this embodiment, when print data is stored in the server 104, the printer 106 stores the second hash value of the print data separately. Therefore, even if the print data of the server 104 is falsified, the second hash value stored in the printer 106 cannot be falsified. Therefore, by comparing the first hash value of the print data existing in the server 104 and the second hash value stored in the printer 106, it is possible to easily determine whether the print data has been tampered with.

  FIG. 3 is a flowchart showing an operation flow when the printer 106 cannot receive the first hash value transmitted from the server 104 due to power interruption or error in the authentication printing system 100 shown in FIG. It is. In the flowchart of FIG. 3, the same operation numbers as those in FIG. 2 are given the same step numbers. The flowchart of FIG. 3 differs from the flowchart of FIG. 2 only in steps S20 and S21. Therefore, a duplicate description will be omitted, and only the flow of operations unique to FIG. 3 will be described.

  In steps S1 to S6, the operation until the client 102 generates print data and transmits it to the server 104, and the server 104 transmits the first hash value included in the print data to the printer 106 is the same as in FIG. It is.

  Here, in step S6, the first hash value is transmitted from the server 104 to the printer 106. If the printer 106 is turned off or some kind of error has occurred, the printer 106 receives the first hash value. The hash value cannot be received. Thereafter, when the printer 106 is turned on or recovered from the error, the printer 106 sends the first hash value of the print data suitable for the model of the printer 106 from the first hash value storage unit 126 to the server 104. A search is requested (step S20). The server 104 transmits the searched first hash value printer 106 (step S21).

  Accordingly, the printer 106 can store the first hash value of the print data suitable for the model in the first hash value storage unit 138 in step S7. Hereinafter, the processing of steps S7 to S17 in FIG. Thus, it is possible to determine whether or not the print data has been tampered with and perform an appropriate print process.

  FIG. 6 is a diagram showing the configuration of the authentication printing system according to the second embodiment of the present invention. Elements having the same functions as those of the first embodiment described with reference to FIGS. 1 to 5 are denoted by the same reference numerals, and redundant description is omitted.

  The main difference of the authentication printing system 200 according to the second embodiment from the authentication printing system 100 according to the second embodiment is that the function of calculating and transmitting the first hash value is not the server 104 but the client. This is a point given to 102. An outline of functions and operations of the authentication printing system 200 is as follows.

  (1) When the client 102 generates print data of a certain user 110, the client 102 calculates a hash value (first hash value) of the print data, and transmits the first hash value to the printer 106. The printer 106 stores the received first hash value.

  (2) The client 102 transmits the generated print data to the server 104. The server 104 stores the received print data in the server 104 until the printer 106 completes printing the print data.

  (3) When authentication of the user 110 is performed, the printer 106 receives the print data of the user 110 from the server 104, calculates a hash value (second hash value) of the received print data, Then, the second hash value is compared with the stored first hash value. If the two hash values match as a result of the comparison, it means that the print data has not been tampered with during storage, and the printer 106 prints out the print data.

  Next, the configuration of the authentication printing system shown in FIG. 6 will be described. Components that are functionally similar to the components shown in FIG. 1 are assigned the same reference numerals, and redundant descriptions are omitted.

  The client 102 includes an authentication print job generation unit 112, an authentication print job transmission unit 114, a first hash value calculation unit 122, a hash value transmission unit 124, and a first hash value storage unit 126. The server 104 includes an authentication print job storage unit 120, an authentication print job request reception unit 130, an authentication print job search unit 132, and an authentication print job transmission unit 134. The configuration of the printer 106 and the authentication device 108 is the same as that of FIG.

  The first hash value calculation unit 122, the hash value transmission unit 124, and the first hash value storage unit 126 in the client 102 exist in the server 104 in the system 100 illustrated in FIG. Since the function is basically the same as the function described with reference to FIG.

  FIG. 7 is a flowchart showing an operation flow of the authentication printing system 200 shown in FIG. Accordingly, the operation flow of the authentication printing system 200 will be described according to the flowchart of FIG. 7 with reference to FIG.

  First, the authentication print job generation unit 112 of the client 102 generates an authentication print job (step S1). The print data of this job is transmitted to the first hash value calculation unit 12 of the client 102, where the first hash value of the print data is calculated (step S4). Further, the calculated first hash value is stored in the first hash value storage unit 126 of the client 102 (step S5). The first hash value in the first hash value storage unit 126 is separated from the original print data (which is stored in the server 104).

  The print data generated by the authentication print job generation unit 112 of the client 102 is transmitted from the authentication print job transmission unit 114 of the client 102 to the authentication print job storage unit 120 of the server 104 (step S2). The authentication print job storage unit 120 of the server 104 temporarily stores it (step S3).

  Further, the first hash value calculated by the first hash value calculation unit 12 of the printer 106 is transmitted from the hash value transmission unit 124 of the client 102 to the hash value reception unit 136 of the printer 106 (step S6). It is stored in the first hash value storage unit 138 (step S7). The first hash value in the first hash value storage unit 138 is separated from the original print data (stored in the server 104).

  The flow of steps S8 to S17 is the same as that of FIG. 2 already described. As a result, the presence or absence of falsification of the print data is determined and an appropriate print process is performed.

  FIG. 8 is a flowchart showing an operation flow when the printer 106 cannot receive the first hash value due to power interruption or error in the authentication printing system 200 shown in FIG. The flowchart of FIG. 8 differs from the flowchart of FIG. 7 only in steps S20 and S21. Therefore, the duplicate description is omitted, and only the flow of operations unique to FIG. 8 will be described.

  In steps S1 to S6, the authentication print job generation unit 112 of the client 102 generates print data and transmits it to the server 104, and the first hash value calculation unit 122 of the client 102 includes the first data included in the print data. The operation until the hash value is calculated and transmitted to the hash value receiving unit 136 of the printer 106 is the same as that in FIG.

  Here, in step S6, when the first hash value is transmitted from the client 102 to the printer 106, if the printer 106 is turned off or some kind of error has occurred, the printer 106 determines the first hash value. The hash value cannot be received. Thereafter, when the printer 106 is turned on or recovered from the error, the printer 106 sends the first hash value of the print data suitable for the model of the printer 106 from the first hash value storage unit 126 to the client 102. Is requested to be searched (step S20). The client 102 searches the first hash value storage unit 126 for the first hash value of the print data suitable for the model of the printer 106, and transmits it to the printer 106 (step S21).

  As a result, the printer 106 can store the first hash value of the print data suitable for the model in the first hash value storage unit 138 in step S7. Therefore, hereinafter, the step of FIG. 2 (or FIG. 7) is performed. Appropriate print processing is performed by determining whether the print data has been tampered with in the same flow as the processing of S7 to S17.

  As mentioned above, although two suitable embodiment of this invention was described, these are the illustrations for description of this invention, and are not the meaning which limits the scope of the present invention only to these embodiment. The present invention can be implemented in various modes different from the above-described embodiments without departing from the gist thereof.

1 is a block diagram showing a configuration of an authentication printing system according to a first embodiment of the present invention. 2 is a flowchart showing a flow of operations of the authentication printing system 100 shown in FIG. 2 is a flowchart showing an operation flow when the printer 106 cannot receive the first hash value in the authentication printing system 100 shown in FIG. FIG. 4 is a diagram illustrating a correspondence between identifiers stored in an authenticated print job storage unit 120 in FIG. 1 and print data. FIG. 4 is a diagram illustrating hash values stored in a first hash value storage unit 138 of the printer 106 illustrated in FIG. 1. The block diagram which shows the structure of the authentication printing system concerning the 2nd Embodiment of this invention. 7 is a flowchart showing an operation flow of the authentication printing system 200 shown in FIG. 6. 7 is a flowchart showing a flow of operations when the printer 106 cannot receive the first hash value in the authentication printing system 200 shown in FIG. 6.

Explanation of symbols

100, 200 Authentication printing system 102 Client 104 Server 106 Printer 108 Authentication device 110 User 112 Authentication print job generation unit 114 Authentication print job transmission unit 120 Authentication print job storage unit 122 First hash value calculation unit 124 Hash value transmission unit 126 First Hash value storage unit 130 Authenticated print job request reception unit 132 Authenticated print job search unit 134 Authenticated print job transmission unit 136 Hash value reception unit 138 First hash value storage unit 139 Hash value search unit 140 Authentication information reception unit 142 Authenticated print job request Unit 143 Authentication print job reception unit 144 Second hash value calculation unit 145 Hash value comparison unit 146 Print output unit 150 Authentication information input unit 152 Authentication information transmission unit

Claims (14)

Print data storage means for storing print data;
First hash value calculating means for calculating a first hash value of the print data;
First hash value storage means for separating and storing the first hash value from the print data;
Second hash value calculation means for calculating a second hash value of the print data stored in the print data storage means at a later time than when the first hash value is calculated;
Comparing means for comparing the second hash value with the first hash value stored in the first hash value storing means;
A printing system comprising: a print output unit that prints out the print data. The printing system according to claim 1.
When the print data is written to the print data storage unit, the first hash value calculation unit calculates the first hash value;
The second hash value calculating means calculates the second hash value when the print output means tries to print out the print data stored in the print data storage means;
Printing system. The printing system according to claim 1 or 2,
A printing system including a plurality of machines, one machine having the print data storage unit, and another machine having the first hash value storage unit. The printing system according to claim 3.
A server communicably connected to a client that outputs the print data;
A printer connected to the server in a communicable manner as the plurality of machines,
The server is
The print data storage means for storing the print data received from the client;
The first hash value calculating means for calculating a first hash value of the print data received from the client;
First hash value transmission means for transmitting the first hash value calculated by the first hash value calculation means to the printer;
Print data transmission means for transmitting the print data in the print data storage means to the printer;
The printer is
First hash value receiving means for receiving the first hash value from the first hash value transmitting means of the server;
The first hash value storage means for storing the first hash value received from the first hash value transmission means of the server;
Print data receiving means for receiving the print data in the print data storage means from the print data transmitting means of the server at a later time than when the first hash value is calculated;
The second hash value calculating means for calculating the second hash value of the print data received from the print data transmitting means of the server;
The comparing means;
A printing system comprising: the print output unit that prints out the print data received from the print data transmission unit of the server. The printing system according to claim 4.
The server further comprises first hash value storage means for storing the first hash value calculated by the first hash value calculation means;
First hash value search means for searching for the first hash value from the first hash value storage means in the server and writing the first hash value storage means in the printer at a predetermined timing; A printing system further provided. The printing system according to claim 3.
A client for outputting the print data;
A server communicably connected to the client;
A printer connected to the client and the server in a communicable manner as the plurality of machines,
The client
The first hash value calculating means for calculating the first hash value of the print data to be output;
First hash value transmission means for transmitting the first hash value calculated by the first hash value calculation means to the printer;
The server is
The print data storage means for storing the print data received from the client;
Print data transmission means for transmitting the print data in the print data storage means to the printer;
The printer is
First hash value receiving means for receiving the first hash value from the first hash value transmitting means of the client;
The first hash value storage means for storing the first hash value received from the first hash value transmission means of the client;
Print data receiving means for receiving the print data from the print data transmitting means of the server at a later time than when the first hash value is calculated;
The second hash value calculating means for calculating the second hash value of the print data received from the print data transmitting means of the server;
The comparing means;
A printing system comprising: the print output unit that prints out the print data received from the print data transmission unit of the server. The printing system according to claim 6.
The client further comprises first hash value storage means for storing the first hash value calculated by the first hash value calculation means;
A first hash value search means for searching for the first hash value from the first hash value storage means in the client and writing the first hash value storage means in the printer at a predetermined timing; A printing system further provided. The printing system according to any one of claims 4 to 7,
The first hash value transmitting means determines whether or not the data format of the print data is compatible with the model of the printer. If the determination result is negative, the first hash value transmission means determines the first hash value of the print data. Omit sending to the printer,
Printing system. First hash value receiving means for receiving a first hash value of print data from an external machine;
First hash value storage means for storing the first hash value received from the external machine;
Print data receiving means for receiving the print data from the external machine or another external machine after the time when the first hash value is calculated;
The second hash value calculating means for calculating a second hash value of the print data received from the external machine or the other external machine;
Comparing means for comparing the second hash value calculated by the second hash value calculating means with the first hash value in the first hash value storage means;
A printer comprising: the print output unit that prints out the print data received from the external machine or the other external machine. In a server that is communicably connected to a client that outputs print data and that is communicably connected to a printer that prints print data,
Print data storage means for receiving and storing print data from the client;
First hash value calculating means for calculating a first hash value of the print data received from the client;
First hash value transmitting means for separating the first hash value from the print data and transmitting the first hash value to the printer;
A server comprising: print data transmission means for transmitting the print data in the print data storage means to the printer at a later time than when the first hash value is calculated. A machine-readable computer program for causing a computer to function as the server according to claim 10. In a client that is communicably connected to a server that stores print data, and that is communicably connected to a printer that receives and prints print data stored in the server,
First hash value calculating means for calculating a first hash value of the print data;
First hash value transmission means for transmitting the first hash value to the printer;
A client comprising print data transmission means for transmitting the print data to the server. A machine-readable computer program for causing a computer to function as the client according to claim 12. Storing print data; and
Calculating a first hash value of the print data;
Separating and storing the first hash value from the print data;
Calculating a second hash value of the stored print data at a later time than when the first hash value is calculated;
Comparing the second hash value with the stored first hash value;
A printing method comprising: printing out the print data.

Images