Encrypted file printing system, encrypted file printing method, and encrypted file print control program

An encrypted file printing method implemented in a system in which a client terminal that generates a print file, an authorization management server that manages authorization of the print file, and an image forming apparatus that performs printing of the print file are connected by a communication network,

• the encrypted file printing method comprising:
• the authorization management server authorizing the print file in response to an authorization request from the client terminal, generating an encryption key for encrypting the print file, and transmitting the encryption key to the client terminal;
• the client terminal receiving the encryption key from the authorization management server, creating an encrypted file by encrypting the print file using the encryption key, adding file information indicating a structure of the print file as metadata to the encrypted file, and transmitting the encrypted file to the image forming apparatus;
• the image forming apparatus
• receiving the encrypted file, and reading the file information added to the encrypted file and calculating a rasterization complexity in the image forming apparatus in accordance with the file information before the encrypted file is decrypted;
• calculating a first processing time in a first processing mode and a second processing time in a second processing mode in accordance with CPU performance information about the image forming apparatus and the authorization management server, information about an allocation of a memory to a rasterization process, the file information, and the rasterization complexity, the first processing mode being a mode where the image forming apparatus performs a decryption process and a rasterization process in parallel, the second processing mode being a mode where the authorization management server performs a decryption process and the image forming apparatus performs a rasterization process;
• and
• comparing the first processing time and the second processing time, and, in accordance with a result of the comparison, determining whether the image forming apparatus or the authorization management server is to perform a decryption process;
• the authorization management server transmitting a decryption key for decrypting the encrypted file when receiving an authorization check request from the image forming apparatus, and decrypting the encrypted file and transmitting the decrypted print file to the image forming apparatus when receiving the encrypted file from the image forming apparatus;
• and
• the image forming apparatus performing a rasterization process on the print file decrypted by the image forming apparatus or the authorization management server.

A non-transitory recording medium storing a computer readable encrypted file print control program to be executed in an image forming apparatus in a system in which a client terminal that generates a print file, an authorization management server that manages authorization of the print file, and the image forming apparatus that performs printing of the print file are connected by a communication network,

• the encrypted file print control program causing a control unit of the image forming apparatus to perform:
• a first process to receive, from the client terminal, an encrypted file generated by encrypting the print file with an encryption key generated by the authorization management server, and receive file information added as metadata to the encrypted file, the file information indicating a structure of the print file;
• a second process to read the file information added to the encrypted file and calculate a rasterization complexity in the image forming apparatus in accordance with the file information before the encrypted file is decrypted;
• a third process to calculate a first processing time in a first processing mode and a second processing time in a second processing mode in accordance with CPU performance information about the image forming apparatus and the authorization management server, information about an allocation of a memory to a rasterization process, the file information, and the rasterization complexity, the first processing mode being a mode where the image forming apparatus performs a decryption process and a rasterization process in parallel, the second processing mode being a mode where the authorization management server performs a decryption process and the image forming apparatus performs a rasterization process;
• and
• a fourth process to compare the first processing time and the second processing time, and, in accordance with a result of the comparison, determine whether the image forming apparatus or the authorization management server is to perform a decryption process.