JP2011081654A - Information processor, program protection system, program protection method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processor for reducing the burden on a program distributor and preventing a decrypted program from being altered or illegally analyzed without using special hardware. <P>SOLUTION: The information processor includes: a program storage means for storing a program for virtual machine generation which is obfuscated by complicating the program while keeping functions to be achieved when the program is executed;and a generation means for generating a virtual machine by executing the program for the virtual machine generation in the program storage means. The virtual machine includes a storage means for storing a decryption key, and a processing means for decrypting an encrypted program using the decryption key in the storage means when receiving the encrypted program and executing the decrypted program. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an information processing apparatus, a program protection system, a program protection method, and a program, and more particularly to an information processing apparatus, a program protection system, a program protection method, and a program that can protect a program.

  A computer used by a user may receive a program distributed from a computer such as a server and execute the program.

  In this case, if the user has malicious intent, the distributed program may be altered by the user. For example, the user may modify the program so that the process of protecting the program from illegal copying is skipped or the score is raised illegally in an online game.

  Moreover, if the contents of the program are known to the user, the technology used in the program may be leaked.

  Non-Patent Document 1 describes a program protection system for protecting a program from a malicious user.

  This program protection system protects a program by performing an obfuscation process on the program. The obfuscation process is a process that complicates the program while maintaining the function realized when the program is executed, and is different from the encryption process. This makes it difficult to analyze a program that has been obfuscated.

  Patent Literature 1 describes a program execution device that protects a program.

  The program execution device accepts and stores a program encrypted using a program key and a program key encrypted using a master key.

  When the program is executed, the program execution device decrypts the encrypted program key using the master key. Subsequently, the program execution device decrypts the encrypted program using the decrypted program key, and executes the decrypted program.

  The program execution device protects the program by storing the encrypted program and the encrypted program key.

  Patent Document 2 describes a data utilization device that protects a program by using special hardware called a processor that can conceal a processor unique key.

  When the data utilization apparatus receives the program encrypted using the content key and the content key, the data utilization device encrypts the content key using the processor specific key, and encrypts the encrypted program and the encrypted content. Store the key.

  Then, when the program is executed, the processor in the data utilization device decrypts the encrypted content key using the processor unique key. Subsequently, the processor decrypts the encrypted program inside the processor using the decrypted content key, places the decrypted program in an internal memory of the processor, and executes the program.

  This data utilization device stores the encrypted program and the encrypted content key, and further protects the program by not outputting the decrypted program to the outside of the processor.

Japanese Patent Laid-Open No. 2005-100378 JP 2004-272594 A

"Tamper resistant technology" [online], JPO, [Search June 4, 2009], Internet <URL http://www.jpo.go.jp/shiryou/s#sonota/hyoujun#gijutsu/info#sec # tech / f-2-2.html>

  When the program protection system described in Non-Patent Document 1 is used, the program distributor must obfuscate the program. In order to obfuscate the program, a dedicated tool corresponding to the programming language is required, and it is not easy to obfuscate the program. For this reason, there is a problem that the burden on the program distributor is large.

  With the technique described in Patent Document 1, it is possible to eliminate the burden of the program distributor obfuscating the program by using the encryption technique. However, since Patent Document 1 does not describe protection for a program decrypted when the program is executed, the decrypted program may be altered or illegally analyzed when the program is executed. There was a problem that occurred.

  With the technique described in Patent Document 2, it is possible to eliminate the burden that the program distributor obfuscates the program by using the encryption technique. Further, in the technique described in Patent Document 2, the decrypted program is decrypted in the processor, and the decrypted program is not output to the outside of the processor, so that the decrypted program is altered or illegally analyzed. It is possible to reduce the possibility of being.

  However, in the technique described in Patent Document 2, the processor unique key can be concealed in order to reduce the burden on the program distributor and prevent the decrypted program from being altered or illegally analyzed. There is a problem that special hardware called a processor must be used.

  In Non-Patent Document 1 and Patent Document 1, the technology that is the premise for the above problem to occur, specifically, the burden on the program distributor is reduced, and the decrypted program is modified or illegally analyzed. There is no description of a technique for preventing this.

  For this reason, the technique described in Non-Patent Document 1 and the technique described in Patent Document 1 naturally reduce the above problem, that is, the burden on the program distributor, and the decrypted program may be altered or illegal. However, the problem that special hardware called a processor capable of concealing the processor unique key must be used has not been solved.

  The objective of this invention is providing the information processing apparatus, program protection system, program protection method, and program which can solve the subject mentioned above.

  The information processing apparatus of the present invention stores a program for generating a virtual machine that has been subjected to an obfuscation process that is a process of complicating the program while maintaining a function that is realized when the program is executed. Generating means for generating a virtual machine by executing a virtual machine generation program in the program storage means, wherein the virtual machine stores storage means for storing a decryption key, and an encrypted program And processing means for decrypting the encrypted program using the decryption key in the storage means and executing the decrypted program.

  The program protection system of the present invention includes the information processing apparatus and a transmission apparatus that transmits the encrypted program to processing means in the information processing apparatus.

  The program protection method of the present invention is a program protection method in an information processing apparatus, and is subjected to an obfuscation process that is a process of complicating the program while maintaining a function realized when the program is executed. A program storage step for storing the virtual machine generation program in the program storage means, a generation step for generating a virtual machine by executing the virtual machine generation program in the program storage means, and a decryption key for the virtual machine A storage step of storing in the storage means, and when the virtual machine receives the encrypted program, the encrypted program is decrypted using the decryption key in the storage means, and the decrypted And a processing step for executing the program.

  The program according to the present invention stores, in a program storage unit, a virtual machine generation program that has been subjected to an obfuscation process, which is a process that complicates the program while maintaining the functions realized when the program is executed. A program storing procedure for storing, a generating procedure for generating a virtual machine by executing a virtual machine generating program in the program storing means, a storing procedure for storing a decryption key in the storing means in the virtual machine, When the virtual machine receives an encrypted program, the virtual machine decrypts the encrypted program using a decryption key in the storage unit, and executes a processing procedure for executing the decrypted program Let

  According to the present invention, the burden on the program distributor is reduced without using special hardware such as a processor capable of concealing the processor unique key, and the decrypted program is modified or illegally analyzed. It becomes possible to prevent that.

It is a block diagram which shows the structure of 1st Embodiment of this invention. It is a flowchart which shows operation | movement of 1st Embodiment. It is a block diagram which shows the structure of 2nd Embodiment of this invention. It is a block diagram which shows the structure of 3rd Embodiment of this invention.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a program protection system according to the first embodiment of the present invention.

  In FIG. 1, the program protection system includes a client machine 100 and a program distributor device 150.

  Client machine 100 can generally be referred to as an information processing apparatus.

  The client machine 100 includes a program storage unit 101, a generation unit 102, a virtual machine 103, a virtual disk 104, a host OS 105, and a physical memory 106.

  Program storage unit 101 can generally be referred to as program storage means.

  The program storage unit 101 stores a virtual machine generation program that has been obfuscated. The obfuscation process means a process for complicating the program while maintaining a function realized when the program is executed.

  As the obfuscation process, for example, the technique described in Non-Patent Document 1 is used. The obfuscation process is not limited to the technique described in Non-Patent Document 1, and can be changed as appropriate. For example, as the obfuscation process, a process of converting a program described in a program language into a machine language that can be executed by a computer may be used.

  The program storage unit 101 stores a virtual disk generation program.

  Generation unit 102 can generally be referred to as generation means.

  The generation unit 102 generates a virtual machine 103 in the client machine 100 by executing a virtual machine generation program in the program storage unit 101.

  In addition, the generation unit 102 generates a virtual disk 104 in the client machine 100 by executing a virtual disk generation program in the program storage unit 101.

  A key 103a1 is embedded in the virtual machine 103. The key 103a1 can be called a decryption key.

  Since the virtual machine 103 is generated according to a virtual machine generation program that has been obfuscated, it is very difficult for a user using the client machine 100 to acquire the key 103a1.

  The virtual disk 104 is a disk for the virtual machine 103. The virtual disk 104 stores an OS (Operating System) 104a for the virtual machine 103 and a key 104b. The key 104b is a key for public key encryption, and includes a public key 104b1 and a secret key 104b2. Similar to a normal PKI (Public Key Infrastructure), the public key 104b1 is signed, and the user can confirm whether the public key 104b1 is a regular public key by confirming the signature. .

  The OS 104 a and the key 104 b are stored in the virtual disk 104 in a state encrypted with the key 103 a 1 in the virtual machine 103.

  Since the key 104b is encrypted, the user of the client machine 100 cannot directly acquire the unencrypted key 104b.

  Furthermore, since the user of the client machine 100 cannot obtain the key 103a1, the information (OS 104a and key 104b) stored in the virtual disk 104 cannot be accurately recognized.

  The virtual machine 103 includes a storage unit 103a, a decryption unit 103b, a guest OS 103c, a virtual memory 103d, and a virtual MMU (Memory Management Unit) 103e. The decryption unit 103b and the guest OS 103c are included in the processing unit 103f.

  Storage unit 103a can generally be referred to as storage means. The storage unit 103a stores a key 103a1 and a random number 103a2.

  When the virtual machine 103 and the virtual disk 104 are generated by the generation unit 102, the decryption unit 103b decrypts information (OS 104a and key 104b) in the virtual disk 104 using the key 103a1 in the storage unit 103a. Subsequently, the decryption unit 103b reads and executes the OS 104a in the virtual disk 104 and activates the guest OS 103c.

  When the guest OS 103c receives the encrypted program 151 from the program distributor device 150, the guest OS 103c decrypts the encrypted program 151 using the key 104b decrypted by the decryption unit 103b, and generates a decrypted program 141. Then, the decrypted program 141 is executed.

  In the present embodiment, the program distributor device 150 encrypts the program 152 using the public key 104b1 to generate the encrypted program 151. Therefore, when the guest OS 103c receives the encrypted program 151, the guest OS 103c decrypts the encrypted program 151 using the secret key 104b2.

  Note that the program distributor 150 may use a hybrid method using a public key method and a common key method instead of the public key method as an encryption method.

  In this case, the program distributor device 150 generates a common key, encrypts the program 152 with the common key, and generates an encrypted program 151. The program distributor 150 further encrypts the common key with the public key 104b1. The program distributor device 150 transmits the encrypted program 151 and the common key encrypted with the public key 104b1 to the guest OS 103c.

  The guest OS 103c decrypts the common key encrypted using the public key 104b1 using the private key 104b2, decrypts the encrypted program 151 using the decrypted common key, and decrypts the decrypted program 141 is generated.

  In this case, the amount of calculation for encryption and decryption of the program can be reduced.

  The guest OS 103c decrypts the encrypted program 151 on the virtual memory 103d, and executes the decrypted program 141 on the sandbox 103d1 in the virtual memory 103d.

  The sandbox 103d1 is used to prevent the decrypted program 141 from accessing other areas on the guest OS 103c. In the case of Linux (registered trademark), Linux-Vserver, OpenVZ, and the like correspond to the sandbox 103d1.

  By using the sandbox 103d1, even if a computer virus is incorporated in the decrypted program 141, the computer virus accesses another decrypted program to change its contents or acquire its contents. You can't do it.

  In this embodiment, the virtual machine 103 uses not only the virtual disk 104 but also the physical memory 106 in the client machine 100 in order to execute the guest OS 103c. The physical memory 106 is divided into a plurality of physical areas (pages).

  By viewing the information stored in the physical memory 106 by a malicious user, the malicious user changes the content of the program being executed in the virtual machine 103 or the content of the program being executed by the virtual machine 103. Or you might be able to get

  In order to prevent this, the virtual MMU 103e in the virtual machine 103 operates as follows. Note that the virtual MMU 103e can be generally referred to as memory management means.

  The MMU is hardware that converts a memory address of a process operating in the OS (memory address of the virtual memory 103 d) into a physical memory address (memory address of the physical memory 106). And exist as virtual hardware (virtual MMU 103e). The memory address is converted in units called pages.

  The virtual memory 103d is divided into a plurality of virtual areas (pages), and each of the virtual areas is associated with one of the plurality of physical areas of the physical memory 106 based on the random number 103a2 in the storage unit 103a. ing.

  The virtual MMU 103e converts a memory address used by a process in the guest OS 103c into a memory address acquired from the host OS 105. For example, when the guest OS 103c accesses the address of the virtual memory 103d, the virtual MMU 103e converts the address into an address of a physical area associated with the virtual area having the address, and uses the address of the physical area. The physical memory 106 is accessed.

  Here, the virtual MMU 103e performs this address conversion using the random number 103a2 in the storage unit 103a. For this reason, unless the physical memory 106 on the host OS 105 is replaced in units of pages, information in the virtual memory 103d used by processes in the guest OS 103c cannot be obtained accurately.

  The random number 103 a 2 used for the conversion exists only in the virtual machine 103. Therefore, when the number of used pages is sufficiently large, it is difficult for a malicious user to restore the information in the virtual memory 103d of the process operating in the guest OS 103c from the information in the physical memory 106. be able to.

  Processing unit 103f can be generally referred to as processing means.

  When receiving the encrypted program 151, the processing unit 103f decrypts the encrypted program 151 using the key 103a1 in the storage unit 103a, and executes the decrypted program 141. In the present embodiment, the processing unit 103f decrypts the encrypted key 104b in the virtual disk 104 using the key 103a1 in the storage unit 103a, and converts the encrypted program 151 into the decrypted key 104b. The decrypted program 141 is executed.

  Program distributor device 150 can generally be referred to as a transmitting device.

  When distributing the program 152, the program distributor device 150 acquires the public key 104b1 from the guest OS 103c. After confirming that the public key 104b1 is a legitimate public key, the program distributor device 150 encrypts the program 152 with the public key 104b1 by the encryption unit 150a to generate the encrypted program 151.

  The program distributor device 150 transmits the encrypted program 151 to the guest OS 103c. The encrypted program 151 may be viewed because it cannot be decrypted even if acquired by the user.

  Next, the operation will be described.

  FIG. 2 is a flowchart for explaining the overall operation of the present embodiment.

  First, in the client machine 100, when the virtual machine 103 and the virtual disk 104 are generated by the generation unit 102, the decryption unit 103b in the virtual machine 103 decrypts the information in the virtual disk 104 using the key 103a1, The guest OS 103c is activated using the decrypted information (OS 104a) (step 200).

  Subsequently, the guest OS 103c passes the public key 104b1 to the program distributor device 150 and requests distribution of the program (step 201).

  The program distributor device 150 receives the public key 104b1 from the guest OS 103c on the client machine 100 (step 210), confirms the validity of the signature of the public key 104b1, and the public key 104b1 corresponds to the leaked secret key. It is confirmed that it is not a public key (step 211).

  If the signature is not valid or the public key 104b1 is a public key corresponding to the leaked secret key, the program distributor device 150 performs error processing (step 212).

  Otherwise, the program distributor device 150 encrypts the program 152 with the public key 104b1 to generate the encrypted program 151 (step 213). When the program distributor device 150 uses the hybrid method as the encryption method, the program distributor device 150 arbitrarily creates a common key in step 213, and uses this common key to create the program 152. And the common key is encrypted with the public key 104b1.

  Subsequently, the program distributor device 150 passes the encrypted program 151 to the guest OS 103c on the client machine 100 (step 214). When the program distributor device 150 uses the hybrid method as the encryption method, the program distributor device 150 uses the encrypted program 151 and the public key 104b1 to the guest OS 103c in step 214. Pass the encrypted common key.

  Subsequently, the guest OS 103c on the client machine 100 acquires the encrypted program 151 (step 202). When the program distributor device 150 uses the hybrid method as the encryption method, the guest OS 103c, in step 202, the encrypted program 151, the common key encrypted with the public key 104b1, and To get.

  Thereafter, the guest OS 103c decrypts the encrypted program 151 using the secret key 104b2 to generate the decrypted program 141. When the program distributor device 150 uses the hybrid method as the encryption method, the guest OS 103c decrypts the encrypted common key with the private key 104b2, and then decrypts the decrypted common key. The decrypted program 151 is generated by decrypting the encrypted program 151.

  Thereafter, the guest OS 103c executes the decrypted program 141 in the sandbox 103d1 (step 203).

  According to the present embodiment, the guest OS 103 c in the virtual machine 103 performs decryption and execution of the encrypted program in the virtual machine 103.

  The virtual machine 103 is generated by executing a virtual machine generation program that has been obfuscated. For this reason, the operation of the virtual machine 103 (the operation of the guest OS 103c) is difficult to analyze.

  Therefore, the possibility that the program decrypted by the guest OS 103c in the virtual machine 103 is modified or illegally analyzed can be reduced. Further, since the virtual machine 103 is used, it is not necessary to use special hardware described in Patent Document 2. In addition, it is possible to eliminate the burden of the program distributor obfuscating the program.

  Note that the client machine including the program storage unit 101, the generation unit 102, the virtual machine 103, and the virtual disk 104 also reduces the burden on the program distributor without using special hardware described in Patent Document 2. At the same time, it is possible to prevent the decrypted program from being altered or illegally analyzed.

  In the present embodiment, random numbers used for associating the virtual area in the virtual memory 103 d with the physical area in the physical memory 106 are stored in the virtual machine 103 that is difficult to analyze.

  For this reason, it becomes difficult to obtain a random number, and thus it is difficult to restore information (for example, the decrypted program 141) in the virtual memory 103d from information in the physical memory 106.

  In this embodiment, the guest OS 103c executes the decrypted program 141 in the sandbox 103d1.

  For this reason, even if a computer virus is incorporated in the decrypted program 141, the computer virus accesses another decrypted program to change the content or acquire the content. Can be prevented.

  Further, in the above embodiment, the key 104 b is present in the virtual disk 104, but the key 104 b may be realized as virtual hardware in the virtual machine 103. In this case, the guest OS 103c acquires the key 104b by accessing the virtual hardware.

(Second Embodiment)
In the first embodiment, the virtual disk 104 and the virtual machine 103 are handled as separate ones, but they may be integrated. In this case, since the virtual disk 104 is taken into the virtual machine 103, it is not necessary to encrypt and decrypt information in the virtual disk 104 using the key 103a1.

  FIG. 3 is a block diagram showing the client machine 100A (second embodiment) in which the virtual disk 104A is taken into the virtual machine 103A. In FIG. 3, the same components as those shown in FIG.

  In FIG. 3, the client machine 100A can be generally called an information processing apparatus.

  The client machine 100A includes a program storage unit 101A, a generation unit 102A, a virtual machine 103A, a host OS 105, and a physical memory 106.

  Program storage unit 101A can generally be referred to as program storage means.

  The program storage unit 101A stores a virtual machine generation program that has been obfuscated.

  Generation unit 102A can be generally referred to as generation means.

  The generation unit 102A generates a virtual machine 103A in the client machine 100A by executing a virtual machine generation program in the program storage unit 101A.

  The virtual machine 103A includes a storage unit 103a, a guest OS 103cA, a virtual memory 103d, a virtual MMU 103e, and a virtual disk 104A.

  In the client machine 100A, the key 103a1 is not stored in the storage unit 103a. In the client machine 100A, the virtual disk 104A is an example of a storage unit, and the key 104b is an example of a decryption key. In the client machine 100A, information in the virtual disk 104A is not encrypted.

  The guest OS 103cA can generally be called a processing unit.

  When the guest OS 103cA receives the encrypted program 151 from the program distributor device 150, the guest OS 103cA decrypts the encrypted program 151 using the private key 104b2, and executes the encrypted program 151 in the sandbox 103d1.

  According to the present embodiment, the guest OS 103cA in the virtual machine 103A performs decryption and execution of the encrypted program 151 in the virtual machine 103A. For this reason, there exists an effect similar to 1st Embodiment.

  Further, according to the present embodiment, the guest OS 103cA does not need to decrypt the information in the virtual disk 104A, and the processing of the guest OS 103cA can be simplified compared to the guest OS 103c of the first embodiment. .

  Note that the client machine including the program storage unit 101A, the generation unit 102A, and the virtual machine 103A can be decrypted while reducing the burden on the program distributor without using special hardware described in Patent Document 2. It is possible to prevent the modified program from being altered or illegally analyzed.

  In the present embodiment, random numbers used to associate the virtual area in the virtual memory 103d with the physical area in the physical memory 106 are stored in the virtual machine 103A that is difficult to analyze.

  For this reason, it is difficult to obtain a random number, and thus it is difficult to restore the information in the virtual memory 103d from the information in the physical memory 106.

  In this embodiment, the guest OS 103cA executes the decrypted program 141 in the sandbox 103d1.

  For this reason, even if a computer virus is incorporated in the decrypted program 141, the computer virus accesses another decrypted program to change the content or acquire the content. Can be prevented.

  Also in the present embodiment, the program distributor apparatus 150 may use a hybrid method using a public key method and a common key method as an encryption method.

  In this case, the program distributor device 150 generates a common key, encrypts the program 152 with the common key, and generates an encrypted program 151. The program distributor 150 further encrypts the common key with the public key 104b1. The program distributor 150 transmits the encrypted program 151 and the common key encrypted with the public key 104b1 to the guest OS 103cA.

  The guest OS 103cA decrypts the common key encrypted using the public key 104b1 using the private key 104b2, decrypts the encrypted program 151 using the decrypted common key, and decrypts the decrypted program 141 is generated.

  In this case, the amount of calculation for encryption and decryption of the program can be reduced.

  In each of the above embodiments, the key 104b may be different for each user.

  In this case, even if the key 104b is leaked, if the public key 104b1 of the leaked key 104b can be known, the program distributor device 150 rejects the program distribution request using the public key 104b1 of the leaked key 104b. As a result, the program 152 to be distributed in the future can be prevented from being altered or leaked.

  In each of the above embodiments, the program is treated as being explicitly encrypted, but communication encrypted between the guest OS and the program distributor device 150 by SSL (Secure Socket Layer) or the like. A path may be configured, and the program may be distributed through the communication path.

(Third embodiment)
Next, a third embodiment of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 4, the third embodiment of the present invention includes a client computer 300 that operates under program control and a server computer 310 that operates under program control.

  The client computer 300 includes a client side program 301.

  For example, the client computer 300 includes a computer-readable recording medium (for example, a bird disk) in which the client-side program 301 is described.

  The client computer 300 functions as the client machine 100 shown in FIG. 1 or the client machine 100A shown in FIG. 3 by reading and executing the client-side program 301 from the recording medium.

  The server computer 310 has a program distribution program 311 installed.

  For example, the server computer 310 includes a computer-readable recording medium (for example, a bird disk) in which the program distribution program 311 is described.

  The server computer 310 functions as the program distributor device 150 shown in FIG. 1 by reading and executing the program distribution program 311 from the recording medium.

  Each of the above embodiments can be applied to uses such as selling and distributing a program. Further, the present invention can also be applied to a case where a server side program is distributed to clients when a Web application is executed offline.

  In each embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

100, 100A Client machine 101, 101A Program storage unit 102, 102A Generation unit 103, 103A Virtual machine 103a Storage unit 103b Decryption unit 103c, 103A Guest OS
103d Virtual memory 103d1 Sandbox 103e Virtual MMU
103f Processing unit 104 Virtual disk 105 Host OS
106 physical memory 150 program distributor 300 client computer 310 server computer

Claims (9)

Program storage means for storing a virtual machine generation program that has been subjected to an obfuscation process, which is a process that complicates the program while maintaining a function that is realized when the program is executed;
Generating means for generating a virtual machine by executing a virtual machine generating program in the program storage means,
The virtual machine is
Storage means for storing a decryption key;
An information processing apparatus comprising: processing means for receiving an encrypted program and decrypting the encrypted program using a decryption key in the storage means and executing the decrypted program. The information processing apparatus according to claim 1,
Further comprising storage means for storing the encrypted key;
The processing means decrypts the encrypted key in the storage means using the decryption key in the storage means, decrypts the encrypted program using the decrypted key, An information processing apparatus that executes the decrypted program. The information processing apparatus according to claim 1 or 2,
Further including physical memory divided into a plurality of physical areas;
The storage means further stores a random number,
The virtual machine is
A virtual memory that is divided into a plurality of virtual areas, and each of the virtual areas is associated with one of the plurality of physical areas based on a random number in the storage unit;
When the processing means accesses the address of the virtual memory, the address is converted into an address of a physical area associated with a virtual area having the address, and the physical memory is used to convert the address into the physical memory. An information processing apparatus further comprising: a memory management means for accessing. In the information processing apparatus according to any one of claims 1 to 3,
The virtual machine further includes a sandbox,
The information processing apparatus, wherein the processing means executes the decrypted program in the sandbox. An information processing apparatus according to any one of claims 1 to 4,
A program protection system comprising: a transmission device that transmits the encrypted program to processing means in the information processing device. A program protection method in an information processing apparatus,
A program storage step of storing in the program storage means a virtual machine generation program that has been subjected to an obfuscation process, which is a process of complicating the program while maintaining the functions realized when the program is executed;
Generating a virtual machine by executing a program for generating a virtual machine in the program storage means;
Storing a decryption key in a storage means in the virtual machine;
When the virtual machine receives an encrypted program, the virtual machine decrypts the encrypted program using a decryption key in the storage means, and executes the decrypted program. Program protection method. The program protection method according to claim 6,
A storage step of storing the encrypted key in the storage means;
In the processing step, the encrypted key in the storage means is decrypted using the decryption key in the storage means, and the encrypted program is decrypted using the decrypted key, A program protection method for executing the decrypted program. On the computer,
A program storage procedure for storing, in the program storage means, a virtual machine generation program that has been subjected to an obfuscation process, which is a process that complicates the program while maintaining the functions realized when the program is executed;
A generation procedure for generating a virtual machine by executing a virtual machine generation program in the program storage means;
A storage procedure for storing the decryption key in the storage means in the virtual machine;
When the virtual machine receives an encrypted program, the virtual machine decrypts the encrypted program using a decryption key in the storage unit, and executes a processing procedure for executing the decrypted program Program to let you. The program according to claim 8, wherein
Causing the computer to further execute a storage procedure for storing the encrypted key in the storage means;
In the processing procedure, the encrypted key in the storage means is decrypted using the decryption key in the storage means, and the encrypted program is decrypted using the decrypted key, A program for executing the decrypted program.

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