JP2010217975A - Information processor, application program, and method for executing application program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To makes it difficult to analyze a program by making it difficult to specify timing when a program to be made secret is arranged in a memory for execution in a decrypted state. <P>SOLUTION: An application 110 includes programs A120 and B140 to be started in parallel with a multi-programming environment. The program B140 includes a partial program 143 to be arranged so as to be encrypted in a memory 11 for execution. The program B140 makes a computer execute: (a) processing for receiving a processing request message from the program A120 by using inter-program communication, and decrypting the partial program 143; (b) processing for calling the decrypted partial program 143, and making it perform an arithmetic operation corresponding to the processing request message; (c) processing for erasing the decrypted partial program 143 from the memory 11 for execution after the completion of an arithmetic operation, and (d) transmitting the arithmetic result to the program A120 by using inter-program communication. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for suppressing leakage of secret information when an application program that handles encrypted digital content is executed by an information processing apparatus.

  The importance of DRM (Digital Rights Management) related to digital contents such as audio, video and programs is increasing. Encryption technology is used to prevent unauthorized use, unauthorized duplication, and falsification of digital content. Specifically, the digital content is encrypted, and the encrypted content is decrypted by the decryption program only when authorized use is performed. However, confidential information such as the decryption procedure of the decryption program and the decryption key used for the decryption process by analyzing the program using the analysis tool such as the disassembler, the memory dump function of the operating system (OS), the debugger program, etc. May be illegally acquired. As techniques for dealing with these program analysis, there are Patent Documents 1 to 4.

  Patent Document 1 discloses that an encrypted program is stored in a file device and decrypted when the program is used. However, in this method, the decrypted program remains in the execution memory (that is, RAM: Random Access Memory) in the information processing apparatus. In this state, the program arranged in the execution memory may be easily obtained using the memory dump function. In addition, the decrypted program may be analyzed by the debugger program.

  Patent Document 2 discloses a technique for preventing program code analysis by replacing a subsequent execution program with a dummy program or stopping program execution when the occurrence of an interrupt by a debugger or the like is detected. However, in the method of Patent Document 2, since the decrypted program is arranged in the execution memory, there is a possibility that the program analysis using the memory dump function cannot be sufficiently handled.

  Patent Document 3 uses a hash value for decryption of encrypted data, and when an unauthorized access by a debugger or the like is detected, the hash calculation procedure is changed to generate a different hash value. A technique for stopping decoding is disclosed. This technique is effective when a hash calculation system that generates a hash value corresponding to a decryption key is hardware-protected and protected from program analysis by a debugger, a memory dump, or the like. However, when the hash value generation is performed by the decryption processing program, the decrypted program is placed in the execution memory. For this reason, there is a possibility that the program analysis using the memory dump function cannot be sufficiently dealt with.

  In Patent Document 4, (i) a program is divided into a plurality of blocks (partial programs) and individually stored in a storage device, and (ii) partial programs are sequentially read out, decrypted and executed. And (iii) overwriting the area in the execution memory where the partial program whose execution has been completed is overwritten with other data (new partial program or dummy data). Thereby, it is possible to shorten the time existing in the execution memory in a state where the specific partial program is decrypted, and to prevent the partial program loaded in the execution memory from being illegally referred to. Patent Document 4 discloses that the position on the execution memory to which the first partial program is loaded is dynamically determined. As a result, since the load position on the execution memory changes each time the program is executed, unauthorized acquisition of the program contents by memory observation predicting the load position is prevented.

  Patent Documents 5 and 6 disclose a technique for dividing content data into a plurality of blocks and performing encryption using different encryption keys for each block. However, these documents do not disclose a technique for dealing with an analysis using a memory dump or a debugger with respect to a decryption program expanded in an execution memory.

JP 2000-122861 A JP 2002-083732 A JP 2006-107274 A JP 2005-018725 A Japanese Patent Laid-Open No. 2004-287466 Japanese Patent Application Laid-Open No. 07-140896

  As described above, the technique disclosed in Patent Document 4 shortens the time that the partial program in the decoded state exists in the execution memory, and changes the position in the execution memory where the partial program is loaded. Thus, it is possible to make program analysis using a memory dump difficult. However, the technique disclosed in Patent Document 4 has a problem that the resistance to the analysis of the program operation using a debugger or the like is not sufficient. Specifically, when a partial program is called directly from an application program by a function call, if the partial program call is specified by the debugger, it is decoded by performing a memory dump at that time. The partial program may be analyzed.

  The present invention has been made in consideration of the above-described problems, and makes it difficult to specify the timing at which the program protected by encryption is placed in the execution memory in a decrypted state. The purpose is to make it difficult to analyze a program using a dump or a debugger, and to improve tamper resistance.

The information processing apparatus according to the first aspect of the present invention includes at least one processor capable of providing a multiprogramming environment and an execution memory. The at least one processor is configured to perform the following processes (a) to (f).
(A) a process of arranging in the execution memory first and second programs started in parallel in the multiprogramming environment;
Here, the second program includes a partial program that is placed in an encrypted form in the execution memory, and the first and second programs can send and receive messages to each other using an inter-program communication function. Is,
(B) processing for transmitting a processing request message from the first program to the second program by inter-program communication;
(C) By executing the second program, the partial program is decrypted when the processing request message is received, and the decrypted partial program is placed in the execution memory;
(D) a process of performing an operation corresponding to the processing request message by executing the partial program after decoding;
(E) a process of erasing the partial program after decoding from the execution memory after completion of the operation by the partial program after decoding;
(F) Processing for transmitting a calculation result by the partial program from the second program to the first program by the inter-program communication.

The application program according to the second aspect of the present invention is executed by a computer including at least one processor capable of providing a multiprogramming environment and an execution memory. The application program includes first and second programs that are started in parallel on the multiprogramming environment. In addition, the second program includes a partial program that is arranged in the execution memory while being encrypted.
The first program causes the computer to perform the following processes (i) and (ii).
(I) processing for transmitting a processing request message from the first program to the second program using an inter-program communication function;
(Ii) Processing for receiving an operation result corresponding to the processing request message from the second program using the inter-program communication function.
The second program causes the computer to perform the following processes (a) to (d).
(A) Decoding the partial program triggered by reception of the processing request message, and placing the partial program after decoding in the execution memory;
(B) processing for calling the partial program after decoding and performing an operation corresponding to the processing request message;
(C) a process of erasing the partial program after decoding from the execution memory after completion of the calculation by the partial program after decoding;
(D) Processing for transmitting the calculation result generated by the partial program after decoding to the first program using the inter-program communication function.

A method according to a third aspect of the present invention is a method for executing an application program in a computer including at least one processor and an execution memory capable of providing a multiprogramming environment. Here, the application program includes first and second programs that are started in parallel on the multi-programming environment. In addition, the second program includes a partial program that is arranged in the execution memory while being encrypted. The method includes the following steps (a) to (f).
(A) arranging the first and second programs in the execution memory;
(B) transmitting a processing request message from the first program to the second program by inter-program communication;
(C) executing the second program to decrypt the partial program triggered by the reception of the processing request message, and placing the decrypted partial program in the execution memory;
(D) performing an operation corresponding to the processing request message by executing the partial program after decoding;
(E) deleting the partial program after decoding from the execution memory after completion of the calculation by the partial program after decoding; and (f) calculating by the partial program using the inter-program communication. Sending the result from the second program to the first program;

  According to the first to third aspects of the present invention described above, it is possible to make it difficult to specify the timing at which the program protected by encryption is placed in the execution memory in a decrypted state. Therefore, it is possible to provide an information processing apparatus, an application program, and an application program execution method that make it difficult to analyze a program using a memory dump or a debugger and improve tamper resistance.

It is a block diagram which shows the structure of the information processing apparatus concerning Embodiment 1 of invention. It is a figure which shows the application program 110 stored in the non-volatile memory 12 of FIG. It is a figure which shows the application program 110 loaded into the memory 11 for execution of FIG. It is a figure which shows a mode that the decrypted partial program 143 is loaded to the execution memory 11. It is a figure which shows a mode that the area | region where the decrypted partial program 143 was arrange | positioned is overwritten. It is a flowchart which shows the execution procedure of the application program in Embodiment 1 of invention. It is a flowchart which shows the execution procedure of the application program in Embodiment 1 of invention. It is a figure which shows the application program 110 stored in the non-volatile memory 12 of FIG. It is a figure which shows a mode that the decrypted content encryption key generation program 143A is loaded to the execution memory 11. It is a figure which shows a mode that the decrypted content decoding program 143B is loaded to the execution memory 11. It is a figure which shows a mode that a program deletion is performed from the memory 11 for execution after content decoding. It is a block diagram which shows the structure of the information processing apparatus concerning Embodiment 2 of invention. It is a conceptual diagram for demonstrating operation | movement of the information processing apparatus shown in FIG. It is a conceptual diagram for demonstrating operation | movement of the information processing apparatus shown in FIG. It is a conceptual diagram for demonstrating operation | movement of the information processing apparatus shown in FIG. It is a conceptual diagram for demonstrating operation | movement of the information processing apparatus shown in FIG. It is a conceptual diagram for demonstrating operation | movement of the information processing apparatus shown in FIG. 12 is a flowchart illustrating a processing procedure of the information processing apparatus illustrated in FIG. 11.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary for the sake of clarity.

<Embodiment 1 of the Invention>
FIG. 1 is a block diagram illustrating a configuration example of the information processing apparatus 1 according to the present embodiment. The processor 10 performs program acquisition, program analysis, and arithmetic processing according to the program analysis result. Although only one processor 10 is shown in FIG. 1, the information processing apparatus 1 may have a multiprocessor configuration having a plurality of processors 10. The processor 10 provides a multi-programming environment by executing an operating system (OS) 100. A multi-programming environment is an environment in which multiple programs are executed in parallel by periodically switching and executing multiple programs, or by switching the programs to be executed in response to the occurrence of a certain event. means.

  Multiprogramming is sometimes called multiprocess, multithread, multitask, and the like. A process, a thread, and a task mean a program unit that is executed in parallel in a multiprogramming environment. Although these terms are often used confusedly, in general, a process is a program module to which a program execution environment such as a memory space is allocated independently and is highly independent of other processes. On the other hand, a thread is a finer parallel processing unit included in processes to be processed in parallel. In a multi-thread environment, a process includes multiple threads. Each thread can access resources allocated to the process, and the threads share a memory space. The multi-programming environment included in the processor 10 of the present embodiment may be a multi-process environment or a multi-thread environment.

  The execution memory 11 is a memory used for program execution by the processor 10. The execution memory 11 stores a program (OS 100 and application program 110) loaded from the nonvolatile memory 12, input / output data of the processor 10, and the like. Specifically, the execution memory 11 may be a random accessible volatile memory such as SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory). Note that the execution memory 11 in FIG. 1 represents a logical unit. That is, the execution memory 11 may be, for example, a combination of a plurality of SRAM devices, a combination of a plurality of DRAM devices, or a combination of an SRAM device and a DRAM device.

  The non-volatile memory 12 is a memory device capable of maintaining stored contents more stably than the execution memory 11 without receiving power supply. For example, the nonvolatile memory 12 is a ROM (Read Only Memory), a flash memory, a hard disk drive, an optical disk drive, or a combination thereof. The nonvolatile memory 12 stores the OS 100 and the application program 110. Further, at least a part of the nonvolatile memory 12 may be configured to be removable from the information processing apparatus 1. For example, the memory storing the application program 110 may be removable. Further, at least a part of the nonvolatile memory 12 may be disposed outside the information processing apparatus 1.

  The OS 100 is executed by the processor 10 to execute task management, memory management, time management, device management, and the like using hardware resources such as the processor 10 and the memories 11 and 12.

  The application program 110 is executed in a multiprogramming environment provided by the processor 10 that executes the OS 100. Hereinafter, the application program 110 is simply referred to as an application 110. FIG. 2 is a diagram illustrating the application 110 in a state of being arranged in the nonvolatile memory 12. The application 110 includes programs A120 and B140. Program A and program B are processed in parallel in the processor 10. Program A and program B may be processes or threads. In the example of FIG. 2, the program B is stored in the memory 12 as the encryption unit 130 in an encrypted state. If the program B140 is encrypted in this way, it becomes difficult to perform a static analysis of the program B140 using the disassembler tool.

  Further, the program B 140 includes a partial program 143 encrypted as the partial encryption unit 142. The partial program 143 is a program that is hidden from the outside. For example, the partial program 143 is a program module (encryption key generation program, content decryption program, etc.) that handles confidential information such as an encryption key necessary for realizing DRM. When the application 110 is activated, the program B140 is loaded into the execution memory 11 after being decoded by the program A120. However, the partial program 143 in the program B 140 is placed in the execution memory 11 while being encrypted. Since the partial program 143 is encrypted, leakage of the partial program 143 can be prevented even when a memory dump of the execution memory 11 in this state is acquired.

  Hereinafter, each program element included in the application 110 illustrated in FIG. 2 will be described. The inter-program communication unit 121 included in the program A 120 uses the inter-program communication (inter-process communication or inter-thread communication) function provided by the processor 10 to use another parallel processing unit (process or thread) including at least the program B 140. ) Is a program module that communicates with the user. As specific mechanisms for realizing the inter-program communication function, pipes, named pipes, sockets, message queues, and the like are known. These known specific mechanisms may be used for inter-program communication between the programs A 120 and B 140 in the present embodiment.

  The encryption unit / decryption program 122 is a program module that decrypts the encryption unit 130 including the encrypted program B140. The program placement unit 123 is a program module that places the decrypted program B140 in the execution memory 11.

  The inter-program communication unit 141 included in the program B is a program module that performs communication with another parallel processing unit (process or thread) including at least the program B140. The partial encryption unit / decryption program 144 is a program module that decrypts the partial encryption unit 142 including the encrypted partial program 143.

  The program placement unit 145 is a program module that places the decrypted partial program 143 in the execution memory 11. The program placement unit 145 may change the load destination area each time the partial program 143 is loaded. By changing the load destination, analysis of the partial program 143 can be made difficult.

  The decoding process of the partial program 143 is performed as follows. The program A120 loaded and started in the execution memory 11 transmits a processing request message for the program B140 by inter-program communication. The program B 140 loaded and activated in the execution memory 11 calls the decryption program 144 in response to the reception of the processing request message from the program A 120 and decrypts the partial program 143. That is, the program A120 does not directly call the program B140 by function call. For this reason, even if the program A120 is analyzed by a debugger or the like, the program B140 cannot be easily analyzed. Therefore, it is possible to make it difficult to specify the timing at which the partial program 143 protected by encryption is placed in the execution memory 11 in a decrypted state.

  The memo risk rumble unit 150 serves to erase data and programs to be concealed from the memory 11. The memo risk rumble unit 150 is a program module that overwrites the storage area in the execution memory 11 with random number data (strictly speaking, pseudo-random number data). The memory risk rumble unit 150 is called from the program A120 or B140, and writes random number data in an area designated by the program A120 or B140. The memo risk rumble unit 150 may generate a random number using, for example, time information each time writing is performed. As a result, the contents of the write data can be changed each time writing is performed. As a result, it is possible to make it difficult to perform program analysis using a technique for specifying an area in the execution memory 11 that is repeatedly overwritten with the same data.

  As will be described later, in the present embodiment, the storage area where the decrypted partial program 143 is placed is overwritten with random number data generated by the memory scrambler 150. Thereby, it is possible to prevent the decrypted partial program 143 from being placed in the execution memory 11 and to effectively prevent the partial program 143 to be concealed from being analyzed. Note that the data written by the memory scrambler 150 may not be random number data. However, the memory scramble unit 150 may change the write data every time writing is performed to the execution memory 11. The write data may be changed randomly or periodically. However, the repetition cycle when changing periodically should be as long as possible.

  FIG. 2 shows an example in which the program B 140 includes one partial encryption unit 142. However, the program B 140 may include a plurality of partial encryption units 142 each including a separate partial program 143 that is encrypted. In this case, in the process of executing the processing according to the processing request message, (i) decryption of the partial encryption unit 142, (ii) execution of the partial program 143, and (iii) execution memory 11 of the decrypted partial program 143 It is preferable that the erasure from is repeated for each partial program 143 in order. That is, it is preferable to avoid a state where a plurality of partial programs 143 for performing a series of processes are simultaneously decoded and arranged in the execution memory 11. Thus, even if a memory dump is obtained when one decrypted partial program 143 is placed in the execution memory 11, the other partial programs 143 are encrypted, so the memory dump It becomes difficult to perform program analysis by using it.

  Subsequently, the transition of the storage state of the execution memory 11 when the programs A120 and B140 are executed will be described below with reference to FIGS. First, FIG. 3 is a diagram illustrating how the decrypted program B140 is loaded. When the application 110 is activated, the encryption unit / decryption program 122 performs a decryption process on the encryption unit 130. The program placement unit 123 places the program B 140 decrypted by the encryption unit / decryption program 122 in the execution memory 11. At this time, since the partial program 143 in the program B 140 is placed in the execution memory 11 in an encrypted state, even if a memory dump of the execution memory 11 in this state is acquired, the partial program 143 Leakage can be prevented.

  FIG. 4 is a diagram illustrating a state in which the program B 140 loads the partial program 143 and performs processing according to the processing request, triggered by transmission of the processing request message from the program A 120 to the program B 140. When receiving a processing request from the application 110, the program A 120 transmits a processing request message from the inter-program communication unit 121 to the inter-program communication unit 141 of the program B 140. The program B140 performs processing according to the content of the message received by the inter-program communication unit 141. Specifically, when the program B 140 receives the processing request message, the partial encryption unit / decryption program 144 performs a decryption process on the partial encryption unit 142. The program placement unit 145 places the partial program 143 decrypted by the partial encryption unit / decryption program 144 in the execution memory 11. Thereafter, the program B 140 calls the partial program 143 arranged in the execution memory 11 and performs processing corresponding to the processing request from the program A.

  FIG. 5 is a diagram illustrating a state in which the storage area in the execution memory 11 in which the partial program 143 is arranged is released after the processing by the partial program 143 is completed. In response to the completion of the processing by the partial program 143, the program B140 requests the memory scrambler 150 to overwrite the storage area where the decrypted partial program 143 is expanded with random number data. In response to this, the memory scrambler 150 writes the random number data in the storage area where the partial program 143 is expanded and then releases the area. The inter-program communication unit 141 of the program B140 transmits a message including a processing result corresponding to the processing request to the inter-program communication unit 121 of the program A120.

  Subsequently, a specific example of the processing procedure from the start to the end of the application 110 will be described below with reference to the flowcharts of FIGS. In step S101, the application 110 is activated. As described above, when the application 110 is activated, the decryption process is performed on the encryption unit 130, and the decoded program B140 is loaded into the execution memory 11 (steps S102 and S103). In step S <b> 104, the program A 120 deletes the encryption unit / decryption program 122 used for decryption of the encryption unit 120 from the execution memory 11. Specifically, the program A120 may request the memory scrambler 150 to overwrite the storage area in which the encryption part / decryption program 122 is arranged with random number data.

  When a processing request is generated from the application 110 to the program A120 (S105), the program A120 transmits a processing request message to the program B140 by inter-program communication (S106). The program B140 analyzes the received processing request message and starts processing according to the message (S107).

  In step S108, the program B140 determines whether or not the partial program 143 needs to be used. When the partial program 143 is used (YES in S108), the partial encryption unit 142 is decrypted by executing the partial encryption unit / decryption program 144 (S109). In step S110, the program placement unit 145 loads the decrypted partial program 143 into the execution memory 11.

  In step S111, the partial program 143 loaded in the execution memory 11 is called to execute processing. In step S112, the processed partial program 143 is deleted from the execution memory 11. Specifically, as described above, the storage area where the decrypted partial program 143 is arranged may be overwritten with random number data.

  In step S113, it is further determined whether or not the partial program 143 needs to be executed. If further execution of the partial program 143 is necessary, the process returns to step S109. On the other hand, if further execution of the partial program 143 is not necessary, the process proceeds to step S114.

  In step S114, the program B140 transmits the processing result obtained by executing the partial program 143 to the program A120 using inter-program communication. In step S115, the program A 120 analyzes the processing result received by the inter-program communication and returns the processing result to the application 110. In step S116, the application 110 performs processing based on the processing result received from the program A120.

  In step S117, the end of application 110 is determined. If the application 110 does not end, steps S105 to S116 are repeated. On the other hand, when the application 110 is terminated (YES in S117), the decrypted program B140 is deleted from the execution memory 11. Specifically, the memory scramble unit 150 is activated and the storage area in the execution memory 11 in which the decrypted program B 140 is arranged is overwritten with random number data. Finally, in step S119, the application 110 ends.

  As described above, the information processing apparatus 1 according to the present embodiment decrypts and loads the partial program 143 to be concealed into the execution memory 11 only when necessary. For this reason, the time during which the decrypted partial program 143 exists in the execution memory 11 is shortened, and the resistance to the program analysis by the memory dump is improved.

  Further, each time the partial program 143 is deleted from the execution memory 11, the information processing apparatus 1 overwrites the storage area in which the partial program 143 is arranged with different data (pseudo-random number data or the like). As a result, it is possible to make it difficult to perform program analysis using a technique for specifying an area in the execution memory 11 that is repeatedly overwritten with the same data.

  In the information processing apparatus 1, the program A 120 transmits a processing request message to the program B 140, and the program B 140 decrypts and loads the partial program 143 in response to reception of the processing request message. That is, since the program A is not explicitly called from the program A by the function call, even if the program A 120 is analyzed by a debugger or the like, the program B 140 cannot be easily analyzed.

  Hereinafter, an example of a specific application destination of the information processing apparatus 1 will be described. Here, a case will be described in which the program B 140 includes two partial programs 143A and B, and the digital content decryption processing is performed using these partial programs 143A and B.

  FIG. 8 is a diagram showing the application 110 before loading, and corresponds to FIG. In the example of FIG. 8, the program B140 includes two partial encryption units 142A and 142B. The partial encryption unit 142A includes an encrypted content encryption key generation program 143A. The partial encryption unit 142B includes an encrypted content decryption program 143B. The encryption key generation program 143A generates an encryption key used for decrypting the digital content. The content decryption program 143B decrypts the digital content using the encryption key generated by the encryption key generation program 143A.

  FIG. 9 shows a state of the execution memory 11 in a state where the application 11 is activated. More specifically, FIG. 9 shows that the program B 140 loads the encryption key generation program 143A and generates the encryption key data 146 when the “content decryption request message” is transmitted from the program A 120 to the program B 140. Is shown. When there is a content decryption request from the application 110, the program A120 transmits a decryption request message from the inter-program communication unit 121 to the inter-program communication unit 141 of the program B140.

  The program B140 performs processing according to the content of the message received by the inter-program communication unit 141. Specifically, when the program B 140 receives the decryption request message, the partial encryption unit / decryption program 144 performs a decryption process on the partial encryption unit 142A. The program placement unit 145 places the encryption key generation program 143A decrypted by the partial encryption unit / decryption program 144 in the execution memory 11. Thereafter, the program B 140 calls the encryption key generation program 143A arranged in the execution memory 11, and performs generation processing of the encryption key data 146. Even if the memory dump in the state shown in FIG. 9 is acquired, it is difficult to analyze the encrypted content decryption program 143B.

  FIG. 10 shows a state where the storage area in the execution memory 11 in which the encryption key generation program 143A is arranged is released after the generation of the encryption key data 146 is completed. FIG. 10 shows how the content decryption program 143B is loaded after the encryption key generation program 143A is deleted. In response to the completion of generation of the encryption key data 146, the program B140 requests the memory scrambler 150 to overwrite the storage area in which the encryption key generation program 143A is expanded with random number data. In response to this, the memory scrambler 150 writes the random number data to the storage area where the encryption key generation program 143A is expanded and then releases the area. Next, the partial encryption unit / decryption program 144 performs a decryption process on the partial encryption unit 142B. The program placement unit 145 places the content decryption program 143B decrypted by the partial encryption unit / decryption program 144 in the execution memory 11. Thereafter, the program B 140 calls the content decryption program 143B arranged in the execution memory 11, and decrypts the digital content using the encryption key data 146.

  FIG. 11 shows a state in which the storage area in the execution memory 11 in which the content decryption program 143B is disposed is released after the decryption of the digital content is completed. The program B140 requests the memory scrambler 150 to overwrite the storage area where the content decryption program 143B is expanded with random number data in response to the completion of the decryption of the digital content. In response to this, the memory scrambler 150 writes the random number data in the storage area where the content decryption program 143B is expanded and then releases the area. At this time, the storage area holding the encryption key data 146 may be released after being overwritten with random number data. As a result, not only the partial program 143 but also temporary data generated by the partial program 143 can be deleted, and leakage can be prevented.

<Embodiment 2 of the Invention>
In this embodiment, (i) the program-generated secret information is encrypted and stored in the memory, (ii) the area for storing the encrypted secret information is changed each time, and (iii) the memory is stored. If the plaintext (non-encrypted) secret information deployed in is no longer needed, the area where the plaintext secret information was stored is overwritten with non-regular data such as pseudorandom numbers and stored. Describe freeing up space. This embodiment can be applied when, for example, the encryption key data 146 shown in FIG.

  FIG. 12 is a block diagram showing a configuration of the information processing apparatus 2 according to the present embodiment. The secret information generation program 24 is a program that generates secret information. The secret information use program 25 is a program that uses the secret information generated by the program 24. For example, the secret information generation program 24 is a program that generates an encryption key, and the secret information use program 25 is a program that performs a decryption process using the encryption key.

  The secret information management unit 23 manages secret information arranged in the memory 21. Specifically, the secret information management unit 23 controls encryption of secret information and erasure of plaintext secret information arranged in the memory 21. The secret information protection device 22 accesses the memory 21 based on the control of the secret information management unit 23, and encrypts the secret information and erases the plaintext secret information.

  Next, the operation of the information processing apparatus 2 will be described with reference to FIGS. FIG. 13 is a diagram showing how the secret information generation program 24 generates secret information. The secret information generation program 24 stores the generated plaintext secret information 211 in the memory 21 (S201 in FIG. 18).

  FIG. 14 is a diagram showing how the plaintext secret information 211 is encrypted. The secret information generation program 24 that has generated the plaintext secret information 211 requests the secret information management unit 23 to encrypt the secret information 211 (S202 in FIG. 18). The encryption processing unit 231 that has received the encryption request from the program 24 requests the variable encryption key generation unit 222 in the secret information protection device 22 to generate a variable encryption key. Here, the variable encryption key is an encryption key for encrypting secret information. The variable encryption key generation unit 222 generates the variable encryption key 212 and stores it in the memory 21 (S203 in FIG. 18). Note that the variable encryption key generation unit 222 may generate a different encryption key each time a variable encryption key is generated in order to deal with the leakage of the variable encryption key.

  The encryption processing unit 231 requests the variable encryption unit 221 to encrypt the secret information 211. The variable encryption unit 221 encrypts the secret information 211 using the variable encryption key 212, and stores the encrypted secret information (encrypted secret information) 213 in the memory 21 (S204 in FIG. 18). In order to make it difficult to specify the storage location of the encrypted secret information 213 in the memory 21, the variable encryption unit 221 may change the storage destination each time the encrypted secret information 213 is generated.

  FIG. 15 is a diagram illustrating how the secret information management unit 23 deletes the plaintext secret information 211. The encryption processing unit 231 requests the memory discard unit 233 to delete the secret information 211 (S205 in FIG. 18). The memory discard unit 233 instructs the memory scramble unit 223 in the secret information protection device 22 to overwrite the storage area of the secret information 211 with random number data. The memo risk rumble unit 223 writes the random number data in the area where the plaintext secret information 211 is stored, and then releases the area (S206 in FIG. 18). Note that the memory scrambler 223 may generate different random numbers each time overwriting is performed in order to cope with program analysis by a method of tracing a storage area that is overwritten by the same data. Even if the memory dump is acquired in the state of FIG. 15, since the plaintext secret information 211 does not exist, it is possible to prevent the secret information 211 from being easily read from the memory 21.

  FIG. 16 is a diagram showing how the encrypted secret information 213 is decrypted in response to a request from the secret information use program 25. The secret information use program 25 requests the decryption processing unit 232 to decrypt the encrypted secret information 213 (S207 in FIG. 18). The decryption processing unit 232 instructs the variable decryption unit 224 in the secret information protection device 22 to decrypt the encrypted secret information 213. The variable decryption unit 224 decrypts the encrypted secret information 213 using the variable encryption key 212, and stores the decrypted secret information 211 in the memory 21 (S208 in FIG. 18). Thereafter, the secret information use program 25 performs a process using the decrypted secret information 211 (S209 in FIG. 18).

  FIG. 17 is a diagram showing how the plaintext secret information 211 is deleted in response to a request from the secret information use program 25. After the process using the decrypted secret information 211 is completed, the secret information use program 25 requests the memory discard unit 233 to delete the secret information 211 from the memory 21 (S210 in FIG. 18). The memory discard unit 233 instructs the memory scramble unit 223 to overwrite the storage area of the secret information 211 with random number data. The memo risk rumble unit 223 writes the random number data in the area where the plaintext secret information 211 is stored, and then releases the area (S211 in FIG. 18).

  As described above, the information processing apparatus 2 according to the present embodiment encrypts the secret information on the memory 21. This makes it difficult to detect secret information by monitoring data changes on the memory 21. In addition, by changing the arrangement destination of the encrypted secret information 213 every time, detection of the secret information by monitoring the memory 21 can be made more difficult.

  Further, the information processing apparatus 2 makes it difficult to detect the storage location of the variable encryption key 212 on the memory 21 and the variable encryption key 212 itself by changing the variable encryption key 212 used for encryption of the secret information every time. be able to.

  Also, when erasing the plaintext secret information 211, the information processing apparatus 2 overwrites the storage area of the plaintext secret information 211 with data having no regularity such as a random number and then releases it. For this reason, the secret information can be protected without leaving the secret information on the memory 21. Moreover, it is good to change the data used for overwriting each time. This makes it difficult to specify the position on the memory 21 where the secret information 211 is developed.

  In the example described above, the case where one piece of secret information 211 is generated is shown, but a plurality of pieces of secret information 211 may be generated by one or a plurality of secret information generation programs 24. In this case, the variable encryption key generation unit 222 may generate a different encryption key for each secret information, and the variable encryption unit 221 may encrypt each secret information with a different encryption key.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention described above.

DESCRIPTION OF SYMBOLS 1, 2 Information processing apparatus 10 Processor 11 Execution memory 12 Non-volatile memory 100 Operating system (OS)
110 Application program 120 Program A
121 inter-program communication unit 122 encryption unit / decryption program 123 program placement unit 130 encryption unit 140 program B
141 Inter-program communication unit 142, 142A, 142B Partial encryption unit 143 Partial program 143A Content encryption key generation program 143B Content decryption program 144 Partial encryption unit / decryption program 145 Program allocation unit 146 Encryption key data 150 Memo risk rumble unit 21 Memory 22 Secret information Protection device 23 Secret information management unit 24 Secret information generation program 25 Secret information use program 211 Plain text secret information 212 Variable encryption key 213 Encrypted secret information 221 Variable encryption unit 222 Variable encryption key generation unit 223 Memo risk rumble unit 224 Variable decryption 231 Encryption processing unit 232 Decryption processing unit 233 Memory discarding unit

Claims (20)

At least one processor capable of providing a multi-programming environment;
Execution memory, and
With
The at least one processor comprises:
(A) a process of arranging in the execution memory first and second programs started in parallel in the multiprogramming environment;
Here, the second program includes a partial program that is placed in an encrypted form in the execution memory, and the first and second programs can send and receive messages to each other using an inter-program communication function. Is,
(B) processing for transmitting a processing request message from the first program to the second program by inter-program communication;
(C) By executing the second program, the partial program is decrypted when the processing request message is received, and the decrypted partial program is placed in the execution memory;
(D) a process of performing an operation corresponding to the processing request message by executing the partial program after decoding;
(E) a process of erasing the partial program after decoding from the execution memory after completion of the operation by the partial program after decoding;
(F) a process of transmitting an operation result by the partial program from the second program to the first program by the inter-program communication;
Configured to do the
Information processing device.   The erasing of the partial program in the process (e) is performed by overwriting the area in the execution memory where the partial program after the decryption is arranged with other data different from the partial program, The information processing apparatus according to claim 1, wherein the other data is changed each time the overwriting process is performed.   The information according to claim 1 or 2, wherein an area in the execution memory in which the partial program after decoding is arranged in the processing (c) is changed every time the partial program after decoding is arranged. Processing equipment. The partial program includes first and second partial programs,
In the process (c), the first and second partial programs are decrypted,
In the process (d), a first calculation result is obtained by executing the first partial program after decoding, and an operation using the first calculation result by executing the second partial program after decoding To obtain the second calculation result,
In the process (f), the second calculation result is transmitted to the first program by the inter-program communication.
The information processing apparatus according to any one of claims 1 to 3. The at least one processor repeatedly performs the processes (c) to (e);
Decoding the first partial program in the previous processes (c) to (e), generating the first operation result by the decoded first partial program, and decoding the first partial program After erasing from the execution memory
In the subsequent processes (c) to (e), the second partial program is decoded, the second calculation result is generated by the decoded second partial program, and the second partial program is decoded. Erasing from the execution memory
The information processing apparatus according to claim 4. The processing request is a request for decrypting encrypted content,
The first partial program includes a description for causing the at least one processor to perform a process of generating an encryption key necessary for decrypting the encrypted content as the first calculation result,
The second partial program is for causing the at least one processor to perform the process of decrypting the encrypted content using the encryption key and generating the decrypted content as the second calculation result. Including description,
The information processing apparatus according to claim 4 or 5. The process (e) further includes overwriting an area in the execution memory where the encryption key has been arranged with other data different from the encryption key,
The information processing apparatus according to claim 6.   The information processing apparatus according to any one of claims 4 to 7, wherein an area in the execution memory in which the first calculation result is arranged is changed every time the first calculation result is generated. . An application program executed on a computer including at least one processor and an execution memory capable of providing a multiprogramming environment,
The application program includes first and second programs that are started in parallel on the multiprogramming environment,
The second program includes a partial program that is arranged in an encrypted manner in the execution memory,
The first program is:
(I) processing for transmitting a processing request message to the second program using an inter-program communication function;
(Ii) processing for receiving an operation result corresponding to the processing request message from the second program using the inter-program communication function;
To the computer,
The second program is:
(A) Decoding the partial program triggered by reception of the processing request message, and placing the partial program after decoding in the execution memory;
(B) processing for calling the partial program after decoding and performing an operation corresponding to the processing request message;
(C) a process of erasing the partial program after decoding from the execution memory after completion of the calculation by the partial program after decoding;
(D) a process of transmitting the calculation result generated by the partial program after decoding to the first program using the inter-program communication function;
Causing the computer to
Application program.   The erasure of the partial program in the process (c) is performed by overwriting the area in the execution memory where the partial program after the decryption is arranged with other data different from the partial program, The application program according to claim 9, wherein other data is changed each time the overwriting process is performed.   The application according to claim 9 or 10, wherein an area in the execution memory in which the partial program after decryption is arranged in the processing (a) is changed every time the partial program after decryption is arranged. program. The partial program includes first and second partial programs,
In the process (i), the first and second partial programs are placed in the execution memory while being encrypted,
In the process (a), the first and second partial programs are decrypted,
In the process (b), a first calculation result is generated by calculation according to the first partial program after decoding, and the first calculation result is calculated by calculation according to the second partial program after decoding. A second calculation result is generated based on
In the process (d), the second calculation result is transmitted to the first program by the inter-program communication.
The application program of any one of Claims 9-11. The second program includes a description for causing the computer to repeatedly perform the processes (a) to (c),
The computer
In the previous processes (a) to (c), the decoding of the first partial program, the generation of the first calculation result by the calculation according to the decoded first partial program, and the decoding After erasing the first partial program from the execution memory,
In the subsequent processes (a) to (c), the decoding of the second partial program, the generation of the second calculation result by the calculation according to the decoded second partial program, and the decoding Erasing the second partial program from the execution memory;
The application program according to claim 12. The processing request is a request for decrypting encrypted content,
The first partial program includes a description for causing the computer to perform processing for generating an encryption key necessary for decrypting the encrypted content as the first calculation result,
The second partial program includes a description for causing the computer to perform a process of decrypting the encrypted content using the encryption key and generating the decrypted content as the second calculation result. ,
The application program according to claim 12 or 13. The process (c) further includes overwriting an area in the execution memory in which the encryption key has been arranged with other data different from the encryption key.
The application program according to claim 14.   The application program according to any one of claims 12 to 15, wherein an area in the execution memory in which the first calculation result is arranged is changed every time the first calculation result is generated. A method for executing an application program in a computer including at least one processor and an execution memory capable of providing a multiprogramming environment,
The application program includes first and second programs that are started in parallel on the multiprogramming environment,
The second program includes a partial program that is arranged in an encrypted manner in the execution memory,
The method
(A) arranging the first and second programs in the execution memory;
(B) transmitting a processing request message from the first program to the second program by inter-program communication;
(C) executing the second program to decrypt the partial program triggered by the reception of the processing request message, and placing the decrypted partial program in the execution memory;
(D) performing an operation corresponding to the processing request message by executing the partial program after decoding;
(E) deleting the partial program after decoding from the execution memory after completion of the calculation by the partial program after decoding; and (f) calculating by the partial program using the inter-program communication. Sending a result from the second program to the first program;
An application program execution method comprising: The partial program includes first and second partial programs,
In the step (c), the first and second partial programs are decrypted,
In the step (d), a first calculation result is obtained by executing the first partial program after decoding, and an operation using the first calculation result by executing the second partial program after decoding To obtain the second calculation result,
In the step (f), the second calculation result is transmitted to the first program by the inter-program communication.
The method of claim 1. The at least one processor repeatedly performs the steps (c) to (e);
Decoding the first partial program in the previous steps (c) to (e), generating the first calculation result by the decoded first partial program, and decoding the first partial program After erasing from the execution memory
In the subsequent processes (c) to (e), the second partial program is decoded, the second calculation result is generated by the decoded second partial program, and the second partial program is decoded. Erasing from the execution memory
The method of claim 18. The processing request is a request for decrypting encrypted content,
The first partial program includes a description for causing the at least one processor to perform a process of generating an encryption key necessary for decrypting the encrypted content as the first calculation result,
The second partial program is for causing the at least one processor to perform the process of decrypting the encrypted content using the encryption key and generating the decrypted content as the second calculation result. Including description,
20. A method according to claim 18 or 19.

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