KR101225749B1 - High-speed password searching device and method using graphic processor - Google Patents

Abstract

Disclosed is a fast password search apparatus using a graphics processor. The high-speed password retrieval apparatus may include a central processing unit which extracts data, which is a target of password comparison, from an encrypted file and generates candidate passwords; And a graphic processor searching for a valid candidate password using the extracted password comparison target data and the generated candidate passwords as parameters. This saves time because the user may not be able to remember the password or find a high-speed password for restoring the encrypted document during the law enforcement forensic investigation.

Description

High-speed password searching device and method using graphic processor

The present invention relates to a password retrieval technique, and more particularly, to a technique for retrieving a password required to restore a file encrypted with a password set by a user.

This study is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Telecommunications Research and Development.

Office files, PDF files, and compressed files, which we use a lot, can be encrypted in the program itself, so users can easily encrypt files. However, this file encryption makes finding evidence difficult during forensic investigations. In addition, if the user does not remember the password even though it is an important file, it is impossible to view or modify the file. In this case, password retrieval software can be used to find the password, or a dedicated hardware such as an FPGA can be used.

Using password retrieval software has the advantage that users can use the software at low or no cost. However, speed is limited because it uses tools that perform sequential CPU operations. Dedicated hardware such as FPGAs, rather than general purpose processors, can be used to decrypt passwords at the fastest speeds. However, dedicated equipment designed only for password retrieval at high cost cannot be used for other purposes, so the cost-effective application is not efficient. Therefore, it is not suitable for general use.

In most popular applications, file encryption is based on a password entered by the user using a cryptographic algorithm and its own encryption mechanism. Accordingly, an object of the present invention is to create a technical scheme of searching for a password at high speed using a graphic processor to restore an encrypted file. In particular, the present invention is to perform the password search by the full search in the graphics processor, to achieve a lower price as well as to search for a password faster than conventional commercial software.

In the high-speed password retrieval apparatus for retrieving a password for decrypting a file encrypted with a user password of the present invention for achieving the above technical problem, extracting the data to be compared passwords from the encrypted file, the candidate password A central processing unit for generating the data; And a graphic processor searching for a valid candidate password using the extracted password comparison target data and the generated candidate passwords as parameters. Here, the graphics processor searches for a valid candidate password through parallel processing.

According to an aspect of the present invention, there is provided a central processing unit including: a password comparison target data extracting unit configured to extract data to be password compared from an encrypted file; A password comparison target data transfer unit configured to transfer the extracted data to the graphic processor; A password candidate generator for generating candidate passwords; A password candidate transfer unit configured to transfer the generated candidate passwords to the graphic processor; And a password output unit configured to output a candidate password found as a valid password by the graphic processor.

According to an aspect of the present invention, the number of candidate passwords generated by the password candidate generator at one time is the same as the parallel processing unit of the graphic processor.

The password candidate generator according to an aspect of the present invention generates new candidate passwords in advance while the graphic processor performs an operation for searching for a valid password.

According to an aspect of the present invention, a graphic processor includes: a password comparison target data storage configured to store password comparison target data extracted by a password comparison target data extraction unit in an internal memory of the graphics processor; A password candidate storage unit for storing candidate passwords generated by the password candidate generator in an internal memory of the graphic processor; And generating the password comparison data for each candidate password through a parallel processing operation using the stored candidate password and the stored partial password comparison target data as parameters, and if the generated password comparison data and the stored password comparison target data match, the candidate password is a valid password. And a password search unit for searching as being.

On the other hand, the high-speed password search method performed in the central processing unit of the present invention for achieving the above-described technical problem, the method comprising the steps of: extracting data that is the target of password comparison from the encrypted file; Transferring the extracted password comparison target data to a graphic processor; Generating candidate passwords; Passing the generated candidate passwords to the graphics processor; And receiving and outputting, by the graphic processor, the candidate password found as a valid password using the password comparison target data and the candidate passwords as parameters.

On the other hand, the high-speed password search method performed in the graphic processor of the present invention for achieving the above technical problem, the step of receiving the password comparison target data extracted from the encrypted file in the central processing unit and storing in the internal memory; Storing candidate passwords generated by the central processing unit in internal memory; Generating password comparison data for each candidate password through a parallel processing operation using the stored candidate password and the stored partial password comparison target data as parameters; Comparing the generated password comparison data with stored password comparison target data; And reporting the candidate password as a valid password to the central processing unit if there is a matching password comparison data as a result of the comparison.

It is much faster than password recovery using password retrieval software. Also, the graphics board used for password retrieval is installed in most computers, so there is little additional cost for password retrieval. Therefore, it can be used for forensic investigation or password recovery if the user cannot remember the password for the encrypted file at a simple and low cost.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and further aspects of the present invention will become more apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings. Hereinafter, the present invention will be described in detail to enable those skilled in the art to easily understand and reproduce the present invention.

1 is a block diagram of a fast password search apparatus.

The fast password search device may be a computer equipped with a graphics processor. The fast password search apparatus of the present invention includes a central processing unit (CPU) 100 and a graphics processor 200. The CPU 100 may include a password comparison target data extraction unit 110, a password comparison target data transfer unit 120, a password candidate generation unit 130, a password candidate transfer unit 140, a graphic processor operation call unit 150, And a password output unit 160. The graphic processor includes a resource setting unit 210, a password comparison target data storage unit 220, a password candidate storage unit 230, and a password search unit 240.

First, the CPU 100 will be described. The password comparison target data extraction unit 110 extracts data to be password comparison from the encrypted file. For example, in the case of Acrobat PDF files, Uentry, Pentry, and IDentry correspond to the data to be compared, and in the case of MS-word / excel / powerpoint files, the Docid, Salt, and Hashedsalt values are used for password comparison. Corresponds to the data. For each application, data information to be extracted for password comparison can be obtained through public information or reverse engineering from each program manufacturer. The password comparison target data extraction unit 110 extracts the corresponding data from the file by using the data information to be extracted for the password comparison for each application. The data extracted by the password comparison target data extraction unit 110 is used to compare with the result calculated by the password search unit 240 of the graphic processor 200 to be described later. In addition, the password comparison target data transfer unit 120 serves to transfer the data extracted by the password comparison target data extraction unit 110 to the memory of the graphic processor 200.

The password candidate generator 130 generates a combinable character that can be used as a password. That is, a new string is created from a total of 95 charsets consisting of 10 numbers, 26 lowercase letters, 26 uppercase letters, and 33 special characters. The candidate password may be a combination of ten numbers or 36 combinations including lowercase letters and numbers. For example, the passwords that can be generated from a new n charset consisting of lowercase English letters and user-selected characters among the 95 charsets above are n if the password is 1 and n ^ 5 if the password is 5 Number of password candidates is generated if there are m passwords.

When the generated candidate password is used as an input value of a hash function or a block password in the password search unit 240 of the graphic processor 200, the password candidate generator 130 may be configured to input the hash or block cipher after the password string. Pad the data or add data as appropriate. For example, in general, when the user password length is not more than 20 bytes and the message-digest algorithm 5 (MD5) hash function is used in the password search unit 240 of the graphic processor 200, the update process or the last padding of the MD5 is performed. The process is previously processed by the password candidate generator 130.

That is, a 64-byte candidate password can be generated by performing padding processing including m-padding and m-length indication from the m-th string in the m-length password string. The password search unit 240 of the graphic processor 200, which will be described later, may operate an MD5 processor function that directly inputs a 64-byte candidate password without MD5 update operation, padding, and length calculation. Preferably, the number of candidate passwords generated at one time is the number that the graphic processor 200 can process at one time and repeats this until it finds a valid user password.

The password candidate transfer unit 140 serves to transfer the candidate passwords generated by the password candidate generator 130 to the memory of the graphic processor 200. In this case, the memory allocation of the graphic processor 200 is twice the memory size required by the password candidates generated at one time by the password candidate generator 130. This is for the CPU 100 to generate a new password candidate while the graphics processor 200 processes the password candidate generated in the CPU operation of the computer. Specifically, a password candidate is generated in the CPU 100, a password comparison operation is performed in the graphic processor 200, and a password comparison is performed in the graphic processor 200 without performing an iterative sequential operation in which the password candidate is generated again in the CPU 100. During the operation, the CPU 100 further generates a password candidate to be used later in the graphic processor 200, thereby further shortening the password search time.

The graphics processor operation caller 150 calls the graphics processor 200 to use the high speed parallel processing of the graphics processor without processing a specific portion of the code to be executed for the high-speed password search by the CPU operation of the computer. Function

The password output unit 160 displays information indicating that one of the password comparison data generated by the password search unit 240 of the graphic processor 200 and the data generated by the password comparison target data extraction unit 110 matches. When received from the 240, the password candidate generator 130 outputs one correct password among the password candidates generated. At this time, if data is padded or data is added so that the password candidate generated by the password candidate generator 130 is suitable for the input size of the graphic processor 200, the password output unit 160 outputs a password string excluding the portion. do.

Hereinafter, the operation of the graphics processor 200 will be described.

The resource setting unit 210 sets a type of memory available in the graphic processor 200. The data stored by the password comparison target data storage 220 is set to use a constant memory, and the data stored by the password candidate storage 230 is set to use a register. A register is used to store data necessary for hash operation performed by the graphic processor 200, and a shared memory capable of high-speed input / output is used to store data necessary for cryptographic operation.

The password comparison target data storage 220 stores the password comparison target data transmitted from the password comparison target data transfer unit 120 in a memory in the graphic processor 200 set by the resource setting unit 210. The password candidate storage unit 230 stores the candidate passwords transmitted from the password candidate transfer unit 140 in a memory in the graphics processor 200 set by the resource setting unit 210.

The password search unit 240 generates new password comparison data using the graphics processor based on the password candidate data stored in the memory in the graphics processor 200, some password comparison data, and a password search mechanism of an individual application. This is compared with the password comparison target data stored in the memory in the graphics processor. In one embodiment, the number of password comparison data generated at one time by the password search unit 240 is the same as the number of password candidates, and the same as the parallel processing unit of the graphics processor. If there is no matching password comparison data in one graphic processor parallel processing, the password search unit 240 generates new password comparison data by inputting new candidate passwords and repeats the process of comparing the password comparison data with the password comparison data. If matched password comparison data is found in the password search unit 240, the corresponding candidate password is reported to the CPU 100 as a valid password.

To help you understand it, we will walk you through the process of finding the password of an encrypted PDF file.

The password comparison target data extraction unit 110 extracts IDentry, Pentry, Oentry, and Uentry, which are password comparison data of the PDF file, and stores the password comparison target data of the graphic processor 200 through the password comparison target data transfer unit 120. Transfer to section 220. In addition, the password candidate generator 130 generates a password candidate and transfers the password candidate to the password candidate storage 230 of the graphic processor 200 through the password candidate transmitter 140. In addition, the graphics processor operation call unit 150 calls the graphics processor 200 to execute the code that requires parallel operation. At this time, the memory setting unit 210 determines the memory type and the allocation size of the data to be stored in the password comparison target data storage unit 220, the password candidate storage unit 230, and the password search unit 240.

The password search unit 240 performs 51 MD5 operations, 20 RC4 operations, and other logic for comparing Oentry or Uentry in each operation of parallel processing using a plurality of password candidates generated at one time. It simultaneously determines whether the input password candidate is a correct password and informs the password output unit. If no matching Uentry or Oentry is found, the parallel operation with the new password candidate is executed. The password output unit 160 outputs one string of matches among the password candidates. In this case, the CPU 100 generates a new password candidate to be used next time while the graphics processor 200 performs the calculation so that both the CPU operation and the graphics processor operation may be simultaneously used.

As described above, the password fast searching apparatus using a graphics processor simultaneously uses a general operation of a computer and parallel processing of a graphic board using a computer equipped with a graphic board. In one embodiment, the graphics board uses a board capable of program development in the CUDA platform, which can be obtained from the homepage of the graphics processor manufacturer.

2 is a flowchart for fast password search performed in a CPU.

The CPU 100 extracts data that is a target of password comparison from the encrypted file and transfers the data to the graphic processor 200 (step S200). In addition, the CPU 100 generates candidate passwords and transmits them to the graphic processor 200 (step S210). The CPU 100, which has passed the candidate passwords to the graphics processor 200, generates new candidate passwords in advance. Then, if a valid candidate password is not found from the graphic processor 200, the CPU 100 transfers the newly generated candidate passwords to the graphic processor 200 and repeats the process of generating a new candidate password. (Step S220). If it is reported from the graphic processor 200 that a valid candidate password has been found, the CPU 100 outputs the corresponding candidate password (step S230).

3 is a flow chart for fast password search performed in a graphics processor.

The graphic processor 200 stores the password comparison target data transmitted from the CPU 100 in an internal memory (step S300). In addition, the graphic processor 200 stores the candidate passwords transmitted from the CPU 100 in the internal memory (step S310). Thereafter, the graphic processor 200 uses the candidate password and some password comparison target data stored in the internal memory as parameters, and generates password comparison data based on a mechanism of an individual application program (step S320). In one embodiment, the graphics processor 200 performs operations on all candidate passwords at once through parallel processing to generate password comparison data. The graphic processor 200 compares the generated password comparison data with data that matches the password comparison target data stored in the internal memory (step S330). If there is a matching password comparison data as a result of the comparison, the graphic processor 200 reports to the CPU 100 that the candidate password is a valid password (step S340). On the contrary, if there is no coincidence password comparison data, the graphics processor 200 sends mismatch information to the CPU 100 (step S350), thereby storing candidate passwords newly transmitted from the CPU 100 in the internal memory and newly performing a comparison operation. Repeat until you find a valid candidate password.

So far I looked at the center of the preferred embodiment for the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

1 is a block diagram of a fast password search device.

2 is a flowchart for fast password search performed in a CPU.

3 is a flow chart for fast password search performed in a graphics processor.

<Explanation of symbols for the main parts of the drawings>

100: central processing unit

110: password comparison target data extraction unit

120: password comparison target data transfer unit

130: password candidate generation unit

140: password candidate delivery unit

150: graphics processor operation call unit

160: password output unit

200: graphics processor

210: resource setting unit

220: password comparison target data storage unit

230: password candidate storage unit

240: password search unit

Claims (20)

delete delete An apparatus for retrieving a password for decryption of a file encrypted with a user password, comprising: A central processing unit which extracts data subject to password comparison from the encrypted file and generates candidate passwords; And A graphic processor searching for a valid candidate password through a parallel processing operation using the extracted password comparison target data and the generated candidate passwords as parameters; , &Lt; / RTI & The central processing unit is: A password comparison target data extraction unit for extracting data to be password comparison from the encrypted file; A password comparison target data transfer unit configured to transfer the extracted data to the graphic processor; A password candidate generator for generating candidate passwords; A password candidate transfer unit configured to transfer the generated candidate passwords to the graphics processor; And A password output unit for outputting a candidate password retrieved with a valid password by the graphic processor; Password fast searching device comprising a. The method of claim 3, And the number of candidate passwords generated by the password candidate generator at one time is the same as a parallel processing unit of a graphic processor. The method of claim 3, And the password candidate generator generates new candidate passwords in advance while the graphics processor performs an operation for searching for a valid password. The method of claim 3, And the password candidate generator generates a candidate password by adding padding processing. The system of claim 3, wherein the central processing unit is: A graphics processor arithmetic caller for calling the graphics processor to execute a specific portion of code to be executed for a password search in the graphics processor; Password fast searching apparatus further comprises. The method of claim 7, wherein And outputting the password output unit excluding the corresponding part if the candidate password is padded to fit the input size of the graphic processor or other data is added. The processor of claim 3, wherein the graphics processor is: A password comparison target data storage unit for storing the password comparison target data extracted by the password comparison target data extraction unit in an internal memory of the graphic processor; A password candidate storage unit for storing the candidate passwords generated by the password candidate generator in an internal memory of the graphics processor; And Using the stored candidate password and the stored partial password comparison target data as parameters, password comparison data for each candidate password is generated through parallel processing, and if the generated password comparison data and the stored password comparison target data match, the corresponding candidate password is generated. A password search unit for searching for a valid password; Password fast searching device comprising a. 10. The method of claim 9, A resource setting unit for setting memory usage in the graphics processor; Password fast searching apparatus further comprises. The method of claim 10, And the resource setting unit sets a memory size for data stored by the password comparison target data storage unit to be equal to the data size extracted by the password comparison target data extracting unit. The method of claim 10, And the resource setting unit sets a memory size for data stored by the password candidate storage unit to be twice as large as a data size generated by the password candidate generator. A central processing unit for retrieving a password for decryption of a file encrypted with a user password, comprising: A password comparison target data extraction unit for extracting data to be password comparison from the encrypted file; A password comparison target data transfer unit configured to transfer the extracted data to a graphic processor; A password candidate generator for generating candidate passwords; A password candidate transfer unit configured to transfer the generated candidate passwords to the graphics processor; A graphics processor arithmetic caller for calling the graphics processor to execute a specific portion of code to be executed for a password search in the graphics processor; And A password output unit for outputting a candidate password retrieved with a valid password by the graphic processor; Central processing unit comprising a. 14. The method of claim 13, And the number of candidate passwords generated by the password candidate generator at one time is the same as a parallel processing unit of a graphic processor. The method of claim 3, wherein the graphics processor A password comparison target data storage unit which receives the password comparison target data extracted from the file encrypted by the central processing unit and stores the data in the internal memory; A password candidate storage unit for storing candidate passwords generated by the central processing unit in an internal memory; And Using the stored candidate password and the stored partial password comparison target data as parameters, password comparison data for each candidate password is generated through parallel processing, and if the generated password comparison data and the stored password comparison target data match, the corresponding candidate password is generated. A password search unit for searching for a valid password; Password fast searching device comprising a. 16. The method of claim 15, A resource setting unit for setting memory usage in the graphics processor; Password fast searching apparatus further comprises. delete delete Extracting data subject to password comparison from the encrypted file in the central processing unit; Transferring the extracted password comparison target data to a graphics processor in a central processing unit; Generating candidate passwords in a central processing unit; Passing the generated candidate passwords to the graphics processor at a central processing unit; Searching for a valid candidate password through a parallel processing operation using the password comparison target data and the candidate passwords as parameters in the graphic processor; And outputting the retrieved legitimate candidate password in a central processing unit, The generating of the candidate passwords may include generating the same number of candidate passwords as the parallel processing unit of the graphic processor. The searching step Receiving the password comparison target data extracted from the encrypted file in the central processing unit and storing the received data in the internal memory; Storing candidate passwords generated by the central processing unit in an internal memory; Generating password comparison data for each candidate password through a parallel processing operation using the stored candidate password and the stored partial password comparison target data as parameters; Comparing the generated password comparison data with the stored password comparison target data; And Reporting to the central processing unit that the candidate password is a valid password if there is password matching data that matches the comparison result; Fast password search method performed in the graphics processor, characterized in that it comprises a. 20. The method of claim 19, Receiving new candidate passwords from the central processing unit if there is no matching password comparison data as a result of the comparison; The password fast searching method performed by the graphic processor further comprising.

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