JP7808022B2 - Authentication device, authentication method, and authentication program - Google Patents

Description

The present invention relates to a system that protects communication data generated by a program executed on a terminal and authenticates its authenticity.

Conventionally, measures to prevent online fraudulent activities have become essential when providing services via the Internet. For example, Non-Patent Document 1 introduces an authentication system that performs additional checks, such as verification by phone or email, on accounts that may be subject to fraudulent use.

Amazon Fraud Detector, Internet <https://aws.amazon.com/jp/fraud-detector/>

When distributing programs from a server to a client terminal, measures to protect these programs are important for protecting intellectual property and preventing unauthorized attacks. In this case, one possible measure is to encrypt the data output by the program to prevent unauthorized data tampering and other such fraud, and to authenticate the legitimacy of the data by verifying that it can be correctly decrypted on the server.

However, if the encryption processing part of the program were discovered, there was a risk that this processing would be overwritten and replaced with malicious data. Therefore, obfuscation is used to make the program structure more difficult to decipher, but its effectiveness is limited.

The present invention aims to provide an authentication system that can increase the obfuscation strength of the program structure that performs encryption processing and protect output communication data from fraud.

The authentication device of the present invention comprises a function generation unit that generates multiple encryption functions for encrypting input data and storing it in an allocated memory area in a predetermined order; a component configuration unit that configures multiple program components to call encryption functions in an order corresponding to the output order of multiple pieces of encryption target data whose output order is fixed; a program generation unit that generates a program that outputs the encrypted data stored in the memory area in the predetermined order; a program distribution unit that distributes the generated program to a user's terminal; and a data decryption unit that, upon receiving encrypted data output by the program from the terminal, decrypts the encrypted data using a decryption algorithm corresponding to the encryption functions. The authenticity of the encrypted data is authenticated based on the success of the data decryption unit, and the decrypted data is then obtained.

The program generation unit may randomly change the execution order of the plurality of program parts.

The program generation unit may replace the name of the function group including the multiple encryption functions with a random value.

The function generation unit may mix multiple encryption methods for the multiple encryption functions.

The authentication method of the present invention includes a function generation step of generating multiple encryption functions for encrypting input data and storing it in allocated memory areas in a predetermined order; a component configuration step of configuring multiple program components so that, for multiple pieces of encryption target data whose output order is fixed, encryption functions are called in an order corresponding to the output order; a program generation step of generating a program that outputs the encrypted data stored in the memory area in the predetermined order; a program distribution step of distributing the generated program to a user's terminal; and a data decryption step of, upon receiving encrypted data output by the program from the terminal, decrypting the encrypted data using a decryption algorithm corresponding to the encryption functions. If the encrypted data is successfully decrypted in the data decryption step, the computer authenticates the authenticity of the encrypted data and obtains the decrypted data.

The authentication program of the present invention causes a computer to function as the authentication device.

This invention increases the obfuscation strength of the program structure that performs the encryption process, thereby protecting output communication data from fraud.

FIG. 1 is a diagram illustrating a functional configuration of an authentication system according to an embodiment. FIG. 1 is a first diagram illustrating a configuration of an encryption processing portion in a conventional program for comparison with an embodiment. FIG. 10 is a second diagram illustrating the configuration of an encryption processing portion in a conventional program for comparison with the embodiment. FIG. 2 is a diagram illustrating a configuration of an encryption processing part of a program generated in an embodiment.

An example of an embodiment of the present invention will be described below.
The authentication system of this embodiment obfuscates the encryption processing portion of the program provided from the authentication device to the terminal, preventing the encryption processing from being rewritten, thereby authenticating that the communication data is normal data generated by the program and performing encrypted communication.

FIG. 1 is a diagram showing the functional configuration of an authentication system 1 according to this embodiment.
The authentication system 1 includes a server 10 (authentication device) that provides a program, and a terminal 20 that executes the provided program and communicates with the server 10 .

The terminal 20 is an information processing device such as a personal computer, tablet, or smartphone that is operated by a user and executes a predetermined program.
When the terminal 20 communicates with the server 10 by executing a program provided by the server 10, the terminal 20 encrypts the data to be output using an encryption function incorporated in the program.

The server 10 is an information processing device equipped with a control unit 11, a memory unit 12, and various input/output interfaces, etc., and by executing a program provided to the terminal 20, it authenticates the validity of data received from the terminal 20 and performs encrypted communication.

The control unit 11 controls the entire server 10 and realizes the various functions of this embodiment by appropriately reading and executing various programs stored in the memory unit 12. The control unit 11 may be a CPU.

The memory unit 12 is a storage area for various programs and data that enable the hardware group to function as the server 10, and may be ROM, RAM, flash memory, a hard disk drive (HDD), etc.

The control unit 11 includes a function generation unit 111, a component configuration unit 112, a program generation unit 113, a program distribution unit 114, and a data decoding unit 115.

The function generation unit 111 receives as input the data to be encrypted, encrypts the input data, and generates a plurality of encryption functions enc1() to encN() for storing the data in allocated storage areas in a predetermined order.
Each of enc1() to encN() is a function that encrypts the input data, sorts it in the order of the subscripts, and stores it in a predetermined storage area.
The encryption methods adopted by these encryption functions may be the same, but a plurality of encryption methods may be mixed.

The component configuration unit 112 configures multiple program components so that, for multiple encryption target data whose output order is fixed, encryption functions are called in an order corresponding to this output order.

The program generation unit 113 generates a program for outputting the encrypted data stored in the memory area by the program components in a predetermined order, i.e., in the order in which it was stored after being correctly sorted in a fixed output order.

Specifically, the component configuration unit 112 divides the original program, which inputs the data to be encrypted, into a1() to aN() in the order in which the data is input, and generates each of them using one or more of enc1() to encN() in that order. The program generation unit 113 then prepares a function encz() that returns the encrypted data stored in a specified memory area in that order, and configures the program so that encz() is called from az(), and the final encrypted data is extracted and sent to the server.

FIG. 2 is a first diagram illustrating the configuration of an encryption processing portion in a conventional program for comparison with this embodiment.
Typically, encryption processing is performed by calling a single function. In the example shown, the program has an encryption function enrypt() that receives data from one or more functions, and a function encz() that returns the encrypted data stored in a memory area.

In other words, multiple functions a1(), a2(), a3(), and a4() each call the encryption function enrypt(), which stores the encrypted data E1, E2, E3, and E4 in the memory area in the order of execution. Then, function az() calls function encz(), which outputs the encrypted data E1, E2, E3, and E4 in that order.

Note that this example assumes an encryption program that receives data in stream format, but if you want to provide a program that encrypts and returns already collected data, you can build it as a wrapper around this set of functions.
Furthermore, it is assumed that the key data used for encryption has been input into the program in advance.

FIG. 3 is a second diagram illustrating the configuration of the encryption processing portion in a conventional program for comparison with this embodiment.
In this example, the program in Figure 2 has been subjected to simple obfuscation to make the function names difficult to read. Here, the function enrypt() in Figure 2 has been obfuscated so that it is difficult to tell from the function name that it is an encryption function, but in terms of the program structure, it is easy to tell that all outputs to the memory area go through the function zeurn().
Therefore, an attacker may be able to overwrite or hook this function zeurn() to modify the output data.

Furthermore, since the function encrypt() encrypts data in the order in which it is called, the execution order of a1() to a4() cannot be changed, and therefore there are limits to the processing that can be performed to obfuscate a program.
Here, a function such as enrypt( ) that is called from multiple places in a program, that is, a function where data input is concentrated, is called a concentration point.

FIG. 4 is a diagram illustrating the configuration of an encryption processing portion of a program generated in this embodiment.
The functions provided as enc1(), enc2(), ... rearrange and encrypt data in the order of their subscripts regardless of the order in which they are executed, and store the data in a storage area.
Furthermore, encz() outputs the encrypted data strings E1, E2, ... that have been output and sorted by enc1(), enc2(), .... Note that the storage area may contain portions in which no values are actually stored, and encz() extracts and outputs only the values that are actually stored from E1, E2, ... for that length.

By generating a program that includes encryption processing in this way, there are no centralized points and it is obfuscated, making it impossible to launch attacks that tamper with all input data by replacing a single function.

The program generating unit 113 may also freely (randomly) change the execution order of the program components a1( ), a2( ), . . .
Furthermore, the program generation unit 113 may replace the name of each function, including the multiple encryption functions, with a random value.

The program distribution unit 114 distributes the program generated by the program generation unit 113 to the user's terminal 20.

When the data decryption unit 115 receives the encrypted data output by the program from the terminal 20, it decrypts the encrypted data using a decryption algorithm corresponding to the encryption function.
The server 10 authenticates the authenticity of the encrypted data by the data decryption unit 115 being able to decrypt the encrypted data, and then acquires the decrypted data.

According to this embodiment, the server 10 prepares multiple encryption functions and fixes the storage destination for the data output by each encryption function, allowing it to sort encrypted data in a predetermined order. This eliminates the centralized point in a normal program where encryption processing is performed, and obfuscates the program structure, making it difficult to decipher the execution location and procedure of the encryption processing. This protects communication data from fraudulent attacks such as the insertion of fraudulent data through rewriting or retransmission attacks.

Here, in a typical encryption program, if the encryption method is known, obtaining the key data allows the output data to be decrypted using a separately prepared program to obtain the original data. However, if the encryption method itself is concealed, such as when an encryption method is designed specifically for a specific application, the original data cannot be easily decrypted from the output data and key data alone. Therefore, the server 10 can further reduce the risk of fraud by suppressing attacks that replace the focal point.

In addition, in the generated program, the order of the encrypted data output does not change regardless of the order in which the program components are executed, making it possible to parallelize multiple program components, which is expected to improve processing efficiency.

Furthermore, the server 10 can further obfuscate the program structure and reduce the risk of fraud by randomly changing the execution order of multiple program components and replacing the names of function groups containing multiple encryption functions with random values when generating a program.

According to this embodiment, for example, unauthorized data communications can be suppressed, which can contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects described in the above-described embodiments are merely a list of the most favorable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments.

The authentication method used by the server 10 (authentication device) is implemented by software. When implemented by software, the programs that make up this software are installed on an information processing device (computer). These programs may be recorded on removable media such as CD-ROM and distributed to users, or may be distributed by being downloaded to the user's computer via a network. Furthermore, these programs may be provided to the user's computer as a web service via a network without being downloaded.

1 Authentication system 10 Server (authentication device)
REFERENCE SIGNS LIST 11 control unit 12 storage unit 20 terminal 111 function generation unit 112 component configuration unit 113 program generation unit 114 program distribution unit 115 data decoding unit

Claims (6)

a function generating unit that generates a plurality of encryption functions for encrypting input data and storing the data in allocated storage areas in a predetermined order;
a component configuration unit that configures a plurality of program components so that encryption functions are called in an order corresponding to a plurality of encryption target data items whose output order is fixed;
a program generating unit that generates a program for outputting the encrypted data stored in the storage area in the predetermined order;
a program distribution unit that distributes the generated program to a user terminal;
a data decryption unit that, upon receiving encrypted data output by the program from the terminal, decrypts the encrypted data using a decryption algorithm corresponding to the encryption function;
an authentication device that authenticates the authenticity of the encrypted data by the data decryption unit being able to decrypt the data, and then acquires the decrypted data; The authentication device described in claim 1, wherein the program generation unit randomly changes the execution order of the multiple program parts. The authentication device described in claim 1 or claim 2, wherein the program generation unit replaces the name of a function group including the plurality of encryption functions with a random value. The authentication device described in claim 1 or claim 2, wherein the function generation unit mixes multiple encryption methods for the multiple encryption functions. a function generation step of generating a plurality of encryption functions for encrypting input data and storing the encrypted data in allocated storage areas in a predetermined order;
a component configuration step of configuring a plurality of program components so that encryption functions are called in an order corresponding to a plurality of encryption target data items whose output order is fixed;
a program generation step of generating a program that outputs the encrypted data stored in the storage area in the predetermined order;
a program distribution step of distributing the generated program to a user terminal;
a data decryption step of receiving encrypted data output by the program from the terminal and decrypting the encrypted data using a decryption algorithm corresponding to the encryption function;
An authentication method in which the computer authenticates the authenticity of the encrypted data by successfully decrypting the data in the data decryption step, and then acquires the decrypted data. An authentication program for causing a computer to function as the authentication device described in claim 1 or claim 2.