CN110516775B - User secret information hiding method based on QR code - Google Patents

Abstract

The invention belongs to the technical field of information security, and discloses a secret information hiding method based on a QR code user, which comprises the steps of firstly generating a position sequence, and generating the position sequence for information hiding by a user by using a secret key and a pseudo-random number generator; and then the user uses the position sequence to hide the secret information into the encoding process of the QR code after encoding the secret information to be hidden. The hidden QR code can be scanned normally to read the cover information, so that the hidden QR code is not easy to draw attention of an attacker. Finally, the secret information can be recovered from the hidden QR code by the user by using the secret key. The invention utilizes the properties of QR codes, pseudo random number generators and information hiding to hide the privacy information of users, and only users with secret keys can read the hidden information. And the hiding and recovering algorithm has low computational complexity, can be used on low-power equipment, and has wide application scenes.

Description

User secret information hiding method based on QR code

technical field

The invention belongs to the technical field of information security, in particular to a method for hiding user secret information based on a QR code.

Background technique

Currently, the closest existing technology: a QR code is a two-dimensional code or matrix barcode that stores data information and is designed to be read by a smartphone. QR stands for Quick Response, which means that the code content should be quickly decoded at a very fast speed. The QR code consists of black modules arranged in a square pattern on a white background. The encoded information can be text, URL or other data. QR codes are designed to allow their content to be decoded at high speed. Therefore, its large capacity and fast decoding speed make the popularity of QR codes grow rapidly all over the world. Nowadays, the built-in cameras of mobile phones generally have the function of recognizing QR codes.

Generally speaking, in order to protect the privacy of the barcode data, the data is usually stored in the back-end database, and the barcode displays the web link of the database. These data can only be obtained after the browser correctly accesses the database. However, because the content of QR code is completely transparent, it is only used as a coding method. Therefore, research in the industry mostly regards it as a data carrier, and does not provide security protection on the coding mechanism of QR code. In the application of QR code, it is mostly used to store the back-end database link to facilitate people's access, but the direct exposure of the network link of the back-end database is likely to cause potential risks such as unnecessary privacy information leakage of users, which may attract the attention of intruders. As a data carrier, QR code does not distinguish between user privacy information and general information. Today, when QR codes are widely used, information security issues such as QR code information privacy and security are important issues we face.

To sum up, the problem in the prior art is that the content of the QR code is completely transparent without any security mechanism protection, and the direct exposure of the network link of the back-end database causes potential risks and may attract the attention of intruders.

Difficulty in solving the above technical problems: Because the coding method of the QR code is transparent, the data display is intuitive, and there is no classification of reading permissions, cryptographic methods such as encryption cannot protect specific data while ensuring that the QR code is normally read by ordinary users. Therefore, a new method is needed to realize the protection of private information without affecting the reading of the normal cover information of the QR code. And since QR code scanners are mainly low-power mobile devices, the computational complexity of the scheme should not be high.

The significance of solving the above technical problems: In the context of the widespread use of QR codes today, secret information hiding methods can be used to distinguish user groups or to distinguish user private information from general information. It can provide user privacy and security protection in some environments that require large capacity and fast reading of QR codes.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a method for hiding user secret information based on QR code

The present invention is achieved in this way, a method for hiding user secret information based on QR codes, in which the user uses a pseudo-random generator to generate a pseudo-random sequence controlled by a user key, and encodes the pseudo-random sequence to obtain a position sequence of hidden information; according to the encoding process of the QR code, the secret information is embedded in the QR code according to the position sequence; the secret recovery process is directly read through the position sequence during the decoding process of the QR code to obtain hidden information.

Further, the method for hiding user secret information based on QR codes includes the following steps:

The first step is to generate a position sequence, and the user uses a key and a pseudo-random number generator to generate a position sequence for information hiding;

In the second step, the user encodes the secret information to be hidden and uses the position sequence to hide the secret information into the encoding process of the QR code;

In the third step, the user can use the key to recover the secret information in the hidden QR code.

Further, the selection of the pseudo-random number generator and QR code in the first step: the user should select a pseudo-random number generator with a period as large as possible to ensure randomness; and determine the version and error correction level of the QR code according to the length of the secret information that needs to be hidden;

Generate position sequence: First, the user generates a sequence with a length greater than the total number of blocks of the current version of the QR code through the pseudo-random number generator controlled by the key. After removing duplicates, take the first c items to ensure that there are no repeated blocks in the first c items. Then iterate through each item c and 0~7, use the pseudo-random number generator controlled by the key to confuse, and obtain a sequence of 8×c, c is the maximum error correction number of the QR code version error correction level; the structure of the sequence is a series of two-dimensional arrays.

Further, the QR code cover information encoding of the second step: before encoding the QR code cover information, it should stop before the QR code calculation and add the mask step, and then calculate the mask type after hiding the information;

Secret information encoding: Encode the secret information that the user needs to hide, and encode the secret information into a binary bit stream suitable for hiding, which can be performed using the QR code data encoding standard, or directly converted using encoding methods such as Ascii code. Hide the length according to the user information and set the length bit in the last two bits of the secret information sequence to facilitate decoding;

Secret information hiding: The user uses the key-generated position sequence and the encoded secret information sequence to hide. According to the position information sequence, the constructed secret sequence code is embedded in turn through the position information of each item in the position. For example, the first item of the position information sequence is (8,1), that is, the first bit data of the secret sequence is covered and embedded into the second bit of the 8th block of the QR code, and the position information sequence is read sequentially to complete the embedding of the secret information. After completing the hidden modification of the QR code data code block, continue the encoding process of the cover QR code to obtain the hidden QR code.

Further, the hidden information recovery in the third step: the user uses the location sequence generated by the key and the hidden QR code to recover the secret information. Remove the mask of the hidden QR code and correct the error; then read the coded secret sequence directly according to the position sequence, and then obtain the user's secret information through decoding.

Another object of the present invention is to provide an information data processing terminal applying the method for hiding user secret information based on QR codes.

To sum up, the advantages and positive effects of the present invention are: the present invention utilizes the nature of the QR code to hide and protect user privacy, and users who do not hold the key cannot obtain the hidden information, and all users can normally scan the QR code information on the cover, which is not easy to arouse the suspicion of attackers. At present, existing security technologies such as QR code hiding mainly use methods such as image hiding and watermarking to hide secret information. However, the capacity of image hiding and watermarking methods is limited by the size of the picture or the size of the QR code picture, and methods such as discrete wavelet transform (DWT), discrete cosine transform (DCT) and discrete Fourier transform (DFT) are used in the hiding process to embed the secret or secret QR code into the frequency domain of the QR code image or hidden cover image, and the computational complexity is extremely high. The hiding algorithm of the invention is simple and efficient, the security is directly controlled by the key, the calculation cost is very low, and at the same time, the privacy of the user is effectively protected, and a security scheme is provided for the QR code.

Based on the characteristics of QR codes that are not easy to be recognized by human eyes and strong error correction, the present invention ensures the security and confidentiality of information such as user identities by means of information hiding; according to the characteristics of QR codes, the hidden QR codes can be scanned and read normally, and are not easily suspected by attackers, ensuring privacy; except for users with keys, other scanners cannot obtain the user's secret information, which ensures security; at the same time, the scheme uses the method of direct reading and writing of plain text, which reduces the computational complexity of hiding/recovering, the system overhead is very low, and the scope of application scenarios can be expanded. It is used in the field of cryptography such as secret sharing, or combined with research fields such as the Internet of Things and cloud computing to protect the privacy of user data that uses QR codes as data carriers.

The present invention is based on a QR code hiding scheme for users' sensitive private information, and can be used for the confidentiality, authentication and integrity of the information of the QR code. The present invention mainly utilizes the property of the QR code to hide information so as to protect the user safety of the QR code. An information hiding scheme that can effectively protect user data in a QR code is provided, so as to simply and efficiently protect user privacy data, and realize authentication and identification of the identity of the scanner.

Description of drawings

FIG. 1 is a flowchart of a method for hiding user secret information based on a QR code provided by an embodiment of the present invention.

Fig. 2 is a flow chart of implementing a method for hiding user secret information based on a QR code provided by an embodiment of the present invention.

Fig. 3 is a flowchart of QR code information hiding provided by an embodiment of the present invention.

Fig. 4 is a recovery diagram of QR code hidden information provided by an embodiment of the present invention.

Fig. 5 is a schematic diagram of the experimental results of the information hiding algorithm provided by the embodiment of the present invention;

In the figure: (a) is the original QR code image without hiding the secret; (b)-(e) are the QR code images after hiding the secret.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Aiming at the problems existing in the prior art, the present invention provides a method for hiding user secret information based on a QR code and an information data processing terminal. The present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the QR code-based user secret information hiding method provided by the embodiment of the present invention includes the following steps:

S101: Generating a position sequence, the user uses a key and a pseudo-random number generator to generate a position sequence for information hiding;

S102: The user encodes the secret information that needs to be hidden and uses the position sequence to hide the secret information in the encoding process of the QR code; the hidden QR code can be scanned normally to read the cover information, so it is not easy to attract the attention of the attacker;

S103: The user can recover the secret information in the hidden QR code by using the key.

As shown in Figure 2, the QR code-based user secret information hiding method provided by the embodiment of the present invention specifically includes the following steps:

(1) Selection of pseudo-random number generator and QR code: users should select a pseudo-random number generator with as large a period as possible to ensure randomness. And the version and error correction level of the QR code are determined according to the length of the secret information that needs to be hidden.

(2) Generate position sequence: the user generates a sequence of length 8×c through the pseudo-random number generator controlled by the key, and c is the maximum error correction number of the error correction level of the QR code version. The structure of the sequence is a string of two-dimensional arrays, such as: [12,1],[22,5],[15,1]. The first item is the position of the changed error correction block, which needs to be selected in the data code block of the QR code to avoid the loss of hidden information caused by the defacement of the QR code. The second item is the position in the data block, and its value should be between 0 and 7. Therefore, there should be no duplicate items in the 8×c sequence, and the 8×c items should be completely traversed.

(3) Coding of QR code cover information: Encoding of QR code cover information should stop before the step of QR code calculation and adding mask. Calculating the mask type after hiding information can make the generated hidden QR code less likely to arouse suspicion.

(4) Secret information encoding: To encode the secret information that the user needs to hide, it is necessary to hide the length according to the user information and set the length bit in the last two bits of the secret information sequence to facilitate decoding.

(5) Secret information hiding: The user uses the position sequence generated by the key and the coded secret information sequence to hide, such as the sequence [12,1], [22,5], [15,1], then write the three digits of the secret sequence into the 12th digit of the QR code, the 22nd digit of the 6th digit, and the 15th digit of the QR code. Then continue the encoding process of the cover QR code to get the hidden QR code.

(6) Hidden information recovery: The user uses the location sequence generated by the key and the hidden QR code to recover the secret information. Remove the mask of the hidden QR code, correct the error, and then directly read the encoded secret sequence according to the position sequence, and then obtain the user's secret information through decoding.

The technical scheme of the present invention will be further described below in conjunction with the accompanying drawings.

1. QR code

The QR code consists of two square modules, white and black, representing the numbers 0 and 1, represented by a 2D matrix. The QR code standard provides 40 QR versions that can encode various data, among which version 1 has the smallest capacity and version 40 has the largest capacity. The version you use depends on the amount of data encoded in alphanumeric, binary, Chinese characters, or a combination thereof, and the level of error correction. In addition, the QR code is very reliable, and even if part of the bar code is dirty or damaged, the data can be read correctly. QR codes employ Reed-Solomon error control coding for error detection and correction. Users can choose 4 error correction levels such as L, M, Q and H. Each level provides different error correction capabilities. Higher error correction levels have better error correction capabilities, but also increase the amount of data to be encoded. The coding process of QR code is mainly divided into three steps. The first step is to generate data blocks. The data codewords are encoded in an interleaved manner, and the error correction codewords are appended to the end of the data codeword sequence, which can minimize the possibility of the QR code becoming undecodable due to partial damage. The second step fills the QR code image, and calculates the mask type and adds the mask according to the QR code standard. After encoding the data codewords, a mask that balances white and black modules is applied to the encoded region. There are a total of 8 mask types (0-7), and choosing a suitable mask type can reduce bad patterns that may confuse the QR code reader. The third step is to add format information and version information.

2. Pseudo-random number generator

Pseudo-random number generators are generated by computers through pseudo-random algorithms and seeds with long periodic random numbers. They are not truly random, since they can actually be calculated, but they have statistical characteristics similar to random numbers, with cryptographically secure pseudo-randomness. That is, given a part of the random sample and the random algorithm, the remaining part of the random sample cannot be efficiently calculated.

3 information hiding

Information hiding is a method of hiding confidential information in a large amount of information to prevent the opponent from discovering it. The methods of information hiding mainly include steganography, digital watermarking technology, visible cipher, submerged channel, hidden protocol and so on.

As shown in Figure 3 and Figure 4, the concrete process of the present invention is as follows:

Step 1: Generate a location sequence L _N .

The user should select an appropriate pseudo-random number generator and set the user key K, and use K and the pseudo-random number generator to generate a sequence of QR code data block number d, in which the label of each block appears only once, and the first c item of d is taken, and c is the error correction level of the QR code version. Each item of the sequence of the first c items is divided into 8 items and rearranged using K and a pseudo-random number generator to obtain a position sequence L _N with a length of 8×c.

Step 2, secret information encoding.

For easier decoding, the hidden secret S needs to be encoded. The length of the length bit is selected according to the version and error correction level of the QR code, and the secret information length code is added to the secret information after the secret information is encoded to obtain the encoded secret information sequence S _N .

Step 3, secret information hiding.

According to the position sequence L _N and the secret information sequence S _N , after the data encoding and filling of the QR code are completed, the secret information sequence S _N is written in the data block area D _QR before calculating the added mask. If the sequence L _N is [12,1], [22,5], [15,1], write the three digits of the secret sequence S _N into the second digit of the 12th block, the sixth digit of the 22nd block and the second digit of the 15th block in D _QR respectively. Then continue the encoding process of the cover QR code to get the hidden QR code.

Step 4. Hidden information recovery.

According to the user secret key K and the hidden QR code data block D _QR after removing the mask and error correction, the user generates the position sequence L _N through the secret key K and directly reads the encoded secret sequence S _N , and obtains the user secret S after decoding.

The technical effects of the present invention will be described in detail below in conjunction with experiments.

Positive experimental data: According to the above scheme, the experimental data using python3 language in the linux environment is as follows: The picture shows the simulation results of the scheme, in which all QR codes are QR codes with version 1-H, and can be scanned and read normally.

Figure 5(a) is the original QR code image without hiding the secret, where the cover data is "Hallo", and the data code block D _QR after encoding the cover data is [64,84,134,22,198,198,240,236,17,246,192,246,119,46,148,193,221,87,192,157,115,154,73 ,193,130,113]. The mask type calculated from the QR code encoding is 7.

Figure 5(be) is the QR code image after hiding the secret, and the cover data are all "Hallo", so the data of the QR code block D _QR before embedding and hiding is the same as that in Figure (a). In the following data, L _N is the position sequence of key generation, and D _QR (hiding) is the hidden QR code data code block.

In Figure 5(b), the hidden secret information is “pwd” and the user key is “1q2w3e4r”.

L_N=[(6,1),(20,7),(20,3),(11,1),(22,4),(11,7),(12,6),(9,0),(9,1),(18,0),(20,1),(22,0),(12,3),(11,3),(12,5),(9,5),(16,7),(20, 0),(16,5),(18,5),(6,4),(18,4),(16,1),(22,6),(16,2),(20,2),(18,3),(22,3),(16,0),(22,7),(9,7),(6,6),(6,0),(11,6),(16,6),(18,6 ),(6,5),(9,4),(11,0),(22,1),(12,0),(20,6),(9,6),(18,1),(20,5),(11,2),(6,3),(9,3),(11,4),(12,7),(20,4),(12,1),(22,5),(22,2), (12,2),(9,2),(12,4),(16,4),(16,3),(6,2),(6,7),(18,7),(18,2),(11,5)]

D _QR (hiding)＝[64,84,134,22,198,198, 21 ,236,17, 15 ,192, 218 , 164 ,46,148,193, 20 ,87, 234 , 157 , 255 ,154, 228 ,193,130,113]

Among them, blocks [6,9,11,12,16,18,20,22] are changed, and the changed part is underlined in D _QR (hiding), because the mask type of the QR code data block after adding secret information is still 7 after calculating the mask, so the hidden QR code has little change compared with Figure (a).

In Figure 5(c), the hidden secret information is “key” and the user key is “1q2w3e4r”.

D _QR ( hiding ) ＝ [ 64,84,134,22,198,198,173,236,17,191,192,184,98,46,148,193,14,87,214,157,243,154,122,193,130,113 ]

Because the user key is the same as in Figure (b), L _N is the same, where [6,9,11,12,16,18,20,22] blocks are changed, and the changed part is marked with an underline in D _QR (hiding), because the QR code data block after adding secret information is calculated and the mask type is 0, so the QR code after hiding changes greatly compared with Figure (a).

In Figure 5(d), the hidden secret information is “pwd” and the user key is “google”

L_N＝[(18,6),(18,0),(6,5),(18,2),(23,3),(15,4),(18,1),(6,6),(4,3),(15,6),(7,1),(7,0),(25,2),(23,5),(6,1),(25,3),(23,1),(18,4) ,(4,4),(12,3),(18,7),(4,5),(7,2),(25,1),(6,3),(23,0),(15,5),(12,6),(4,2),(15,3),(23,2),(25,7),(25,6),(23,6),(6,7),(7,4),(12 ( 23,7),(12,2),(12,1),(6,0),(12,5),(4,0),(6,4),(25,5),(15,7)]

D _QR (HIDING) = [64,84,134,22, 207 , 198, 196 , 222 , 17,246,192,246, 137 , 46,148, 162 , 221,88, 157,115,154,73, 174 , 130, 148 ] 148] 148, 148] 148, 148] 148, 148, 148, 148, 148, 148, 148] 148, 148, 148, 148, 148, 148, 148, 148, 148, 148 , 148, 148, 148, 148, 148].

Among them, blocks [4, 6, 7, 12, 15, 18, 23, 25] have been changed, and the changed part is underlined in D _QR (hiding). Because the QR code data block after adding secret information is calculated and masked, the mask type is 5, so the QR code after hiding changes greatly compared with Figure (a) and Figure (c).

In Figure 5(e), the hidden secret information is "key" and the user key is "google"

D _QR ( hiding ) ＝ [ 64,84,134,22,201,198,39,75,17,246,192,246,223,46,148,134,221,87,205,157,115,154,73,189,130,218 ]

Because the user key is the same as in Figure (d), L _N is the same, where the [4,6,7,12,15,18,23,25] block is changed, and the changed part is underlined in D _QR (hiding), because the QR code data block after adding secret information is calculated and the mask type is 5, so the hidden QR code has a large change compared with Figure 5(a) and Figure 5(c), and a small change compared with Figure 5(d).

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. A user secret information hiding method based on a QR code, characterized in that, the user of the QR code user secret information hiding method uses a pseudo-random generator to generate a pseudo-random sequence controlled by a user key, and encodes the pseudo-random sequence to obtain a position sequence of hidden information; according to the encoding process of the QR code, the secret information is embedded in the QR code according to the position sequence; the secret recovery process is then directly read through the position sequence in the decoding process of the QR code to obtain the hidden information; Described user's secret information hiding method based on QR code comprises the following steps: The first step is to generate a position sequence, and the user uses a key and a pseudo-random number generator to generate a position sequence for information hiding; In the second step, the user encodes the secret information to be hidden and uses the position sequence to hide the secret information into the encoding process of the QR code; In the third step, the user can use the key to recover the secret information in the hidden QR code; The selection of the pseudo-random number generator and QR code of the first step: the user should select a pseudo-random number generator with a period as large as possible to ensure randomness; and determine the version and error correction level of the QR code according to the length of the secret information that needs to be hidden; Generate position sequence: the user generates a sequence of length 8×c through the pseudo-random number generator controlled by the key, and c is the maximum error correction number of the error correction level of the QR code version; the structure of the sequence is a string of two-dimensional arrays; The QR code cover information encoding of the second step: before the QR code cover information is encoded, the QR code calculation and adding mask step should be stopped, and the mask type is calculated after hiding the information; Secret information encoding: encode the secret information that the user needs to hide, and set the length bit in the last two digits of the secret information sequence according to the hidden length of the user information to facilitate decoding; Secret information hiding: the user uses the position sequence generated by the key and the encoded secret information sequence to hide; continue the encoding process of the cover QR code to get the hidden QR code; The hidden information recovery in the third step: the user uses the position sequence generated by the key and the hidden QR code to recover the secret information; removes the mask of the hidden QR code and corrects errors; then directly reads the encoded secret sequence according to the position sequence, and then obtains the user's secret information through decoding. 2. An information data processing terminal applying claim 1 based on the QR code user secret information hiding method.