A processing method based on digital watermark encryption and embedding

Abstract

The present invention relates to the field of data encryption technology, and specifically to a processing method based on digital watermark encryption and embedding, including binary conversion of secret information to obtain conversion information; encrypting the conversion information using a national secret algorithm to obtain a ciphertext code; writing the ciphertext code into a pixel matrix using a site scrambling algorithm to obtain a ciphertext image, firstly encoding a bit string of secret information using DNA coding technology, and then using the SM2 national secret algorithm to obtain the ciphertext string through digital signature and encryption, at which time the secret information itself has good security. In the process of embedding the carrier image, the site scrambling algorithm is used to scramble the sites where the secret information is embedded into the image pixel points, so as to achieve the effect that the distribution of the secret information in the carrier image is non-continuous, effectively increasing the difficulty of being attacked and broken through, thereby solving the problem of low security of the existing digital watermark information.

Description

Technical Field

[0001] The present invention relates to the technical field of data encryption, and in particular to a processing method based on digital watermark encryption and embedding. Background Art

[0002] In the context of big data, data has become an important asset.

[0003] The traditional LSB algorithm embeds secret information through continuous pixels. However, due to the continuity and regularity of the embedded pixels, it is easy to find the hidden information in the image through data analysis, which leads to information leakage. Summary of the invention

[0004] The purpose of the present invention is to provide a processing method based on digital watermark encryption and embedding, aiming to solve the problem of low security of existing digital watermark information.

[0005] To achieve the above object, the present invention provides a processing method based on digital watermark encryption and embedding, comprising the following steps:

[0006] Perform binary conversion on the secret information to obtain conversion information;

[0007] Encrypt the conversion information using a national secret algorithm to obtain a ciphertext code;

[0008] The ciphertext code is written into a pixel matrix through a site scrambling algorithm to obtain a ciphertext image.

[0009] The specific method of performing binary conversion on the digital watermark information to obtain the converted information is as follows:

[0010] The secret information is converted into binary according to the ASCII rule to obtain the converted information.

[0011] The specific method of encrypting the conversion information using the national secret algorithm to obtain the ciphertext code is:

[0012] Encoding the conversion information using a coding technique to obtain a bit string of the conversion information;

[0013] The bit string of the conversion information is digitally signed and encrypted using a national secret algorithm to obtain a ciphertext code.

[0014] The specific method of writing the ciphertext code into the pixel matrix through the site scrambling algorithm to obtain the ciphertext image is:

[0015] Transform the original image to obtain a pixel matrix;

[0016] Performing digital signature verification on the ciphertext code to obtain an information sequence;

[0017] Determining an embedding point of the ciphertext code based on the information sequence;

[0018] The ciphertext code is embedded in the pixel matrix according to the embedding point to obtain a ciphertext image.

[0019] Wherein, the encoding technology is DAN encoding technology.

[0020] The processing method based on digital watermark encryption and embedding of the present invention performs binary conversion on secret information to obtain conversion information; encrypts the conversion information using a national secret algorithm to obtain a ciphertext code; writes the ciphertext code into a pixel matrix using a site scrambling algorithm to obtain a ciphertext image, firstly encodes the bit string of the secret information using DNA coding technology, and then uses the SM2 national secret algorithm to obtain the ciphertext string through digital signature and encryption. At this time, the secret information itself has good security. In the process of embedding the carrier image, the site scrambling algorithm is used to scramble the sites where the secret information is embedded into the image pixels, so that the distribution of the secret information in the carrier image is non-continuous, which effectively increases the difficulty of being attacked and broken through, thereby solving the problem of low security of the existing digital watermark information. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a flow chart of a processing method based on digital watermark encryption and embedding provided by the present invention.

[0023] Figure 2 It is a schematic diagram of a technical solution of a processing method based on digital watermark encryption and embedding provided by the present invention.

[0024] Figure 3 It is a flowchart of information sequence preprocessing.

[0025] Figure 4 This is a schematic diagram of the site scrambling algorithm.

[0026] Figure 5 This is a PSNR performance comparison chart. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0028] See also Figures 1 to 5 The present invention provides a processing method based on digital watermark encryption and embedding, comprising the following steps:

[0029] S1 performs binary conversion on the secret information to obtain conversion information;

[0030] The secret information is converted into binary according to the ASCII rule to obtain the converted information.

[0031] Specifically, the generated watermark information, i.e., secret information, is encoded from a string form into a binary form according to the ASCII rule so that the information can be applied to the encryption algorithm.

[0032] S2 encrypts the conversion information using a national secret algorithm to obtain a ciphertext code;

[0033] S21 uses a coding technique to encode the conversion information to obtain a bit string of the conversion information;

[0034] The encoding technology is DAN encoding technology;

[0035] Specifically, according to the DNA coding rules, the bit string obtained in step a is encoded. For example, if the bit string is 1001, it is encoded according to DNA coding method 1 and decoded according to DNA coding method 3, that is, the bit string 1100 is obtained, and finally the coding value M' is obtained. The DNA coding method is shown in Table 1.

[0036] Table 1 DNA encoding

[0037]

[0038] S22 uses the national secret algorithm to digitally sign and encrypt the bit string of the conversion information to obtain a ciphertext code.

[0039] Specifically, information is encrypted through the SM2 national encryption algorithm and then digitally signed. By adopting the digital signature first, the verification signature can be used in the information decryption stage. This processing method can effectively ensure the uniqueness of the decryptor and increase the difficulty of decryption for attackers.

[0040] S3 writes the ciphertext code into the pixel matrix through a site scrambling algorithm to obtain a ciphertext image.

[0041] S31 converts the original image to obtain a pixel matrix;

[0042] Specifically, by taking the RGB three channels of the image, setting the pixel matrix to the pixel points of the RGB three channels, such as (110, 110, 110), and converting the pixel point values ​​into binary, the secret information can be embedded in the pixel points of the corresponding image. This processing method is conducive to embedding the secret information into the carrier image.

[0043] S32 performs digital signature verification on the ciphertext code to obtain an information sequence;

[0044] Specifically, the location where the information will be embedded is determined according to the sequence, effectively ensuring the discontinuity and irregularity of the information distribution in the carrier image pixels, and performing digital signature verification according to the given elliptic curve parameters and the user name, and finally obtaining a signed sequence, as shown in the following steps:

[0045] A1.

[0046] A2. Calculation Convert the data type of e to an integer;

[0047] A3. Generate a random number k∈[1,n-1] using a random number generator;

[0048] A4. Calculate the elliptic curve point (x1, y1) = [k] G;

[0049] A5. Calculate r = (e + x1) mod n. If r = 0 or r + k = n, return to A3.

[0050] A6. Calculate s = ((1 + d A ) -1 ×(kr×d A ))mod n, if s=0, return to A3;

[0051] d A is the private key;

[0052] A7. Convert the data types of r and s to byte strings. The signature of message M is (r, s).

[0053] The elliptic curve used is Fp-256, the elliptic curve equation is y2=x3+ax+b, the base point G=(xG,yG), its order is n, the private key is dA, the public key is PA=(xA,yA), M is the message to be signed, the hash value ZA=H256(ENTLA||IDA||a||b||xG||yG||xA||yA) H256 is the SM3 hash algorithm, H vIt is the SM2 signature algorithm. User A as the signer has an identifiable identifier IDG of length entlenA bits (the user identifier can be converted into ASCII code). Note that ENTLA is two bytes converted from the integer entlenA.

[0054] S33 determines the embedding point of the ciphertext code based on the information sequence;

[0055] S34 embeds the ciphertext code into the pixel matrix according to the embedding point to obtain a ciphertext image.

[0056] Specifically, the sequence is encrypted with a public key, and finally the information M3 to be embedded in the carrier image is obtained. The steps are as follows:

[0057] A1. Use a random number generator to generate a random number k∈[1,n-13];

[0058] A2. Calculate the elliptic curve point C = [k] G = (x1, y1), and convert the data type of C into a bit string;

[0059] A3. Calculate the elliptic curve point S = [h] P B , if S is a point at infinity, an error is reported and the program exits;

[0060] A4. Calculate elliptic curve point [k]P B =(x2,y2), convert the data type of coordinates x2,y2 to a bit string;

[0061] A5. Calculate t = KDF(x2||y2,klen). If t is a string of all 0 bits, return to A1.

[0062] A6. Calculate C2 = M ⊕ t;

[0063] A7. Calculate C3 = Hash(x2||M||y2);

[0064] A8. Output ciphertext C=C1||C3||C2.

[0065] Where n is the length of the encrypted information M, the public key is PB = (xB, yB), h is the cofactor used to verify B's public key PB, and KDF indicates that x2||y2 is used as a parameter to generate a key stream of length klen. Hash is the SM3 hash function.

[0066] The site scrambling algorithm is used. The basic idea of ​​the algorithm is to first generate a pseudo-random sequence Seq1...Seqm through a pseudo-random generator, and then use two keywords with an increment of d in the Seq sequence to form two adjacent embedding points until the sequence position order is disrupted to generate a new two-dimensional sequence P. The formula is as follows:

[0067] P[2i]=seq[i+d]

[0068] Where m is the length of the sequence, i is the coordinate position of the sequence, and d is the artificially set increment;

[0069] The final embedding sequence F is determined by two remainder calculations to determine the specific position of the embedded two-dimensional sequence P. At the same time, the time seed factor is added to the remainder calculation to affect the irregularity of the embedding distribution. The formula is as follows:

[0070] L=(m[i]1*d+t)mod(P1)

[0071] R=(m[i]2*d+t)mod(P2)

[0072] F=P(L,R)

[0073] Among them, m1 and m2 are the first four and last four digits of the ASCII binary code corresponding to the secret information, t is the time seed, and P1 and P2 are the length and width of the two-dimensional sequence P. The algorithm processing makes the arrangement of the secret information in the carrier image non-continuous, and the secret information will not have an obvious dividing line in the carrier image, that is, the attacker cannot analyze the data to find out which pixel of the carrier image the secret information is hidden in.

[0074] The present invention is compared with the LSB method and the algorithms mentioned in references [1] and [2]. It can be clearly seen in the table that under the same embedding amount, the pseudo-random algorithm adopted by the present invention has better image quality after the secret information is embedded in the image than several existing steganographic algorithms. Even if the embedding capacity is as high as 21368 bits, the PSNR value remains above 60 dB. The images used in the experiment are color images in the UCID image database. Three randomly selected standard test color images (Lena, Baboon, Peppers) are mainly used to determine the performance of the improved algorithm. The test results are shown in Table 2.

[0075] 1. Compared with the traditional digital watermark processing scheme that simply embeds secret information into the image, the present invention processes the secret information before watermark embedding, and innovatively proposes to combine DNA coding technology with SM2 encryption algorithm to encrypt the secret information. The processed secret information has higher security.

[0076] 2. The traditional LSB method embeds secret information into a series of continuous pixel points in the image. This method makes the embedded information easier to be extracted by attackers. The present invention, while inheriting the advantages of the LSB method such as fast processing speed, proposes a site scrambling algorithm. According to a pseudo-random generator, the secret information is embedded in the corresponding pixel points of the generated sequence, which increases the discontinuity and irregularity of the arrangement of the secret information in the carrier image.

[0077] What is disclosed above is only a preferred embodiment of the processing method based on digital watermark encryption and embedding of the present invention. Of course, it cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A processing method based on digital watermark encryption and embedding, characterized in that: The following steps are involved: Performing binary conversion on the secret information to obtain conversion information, wherein the generated watermark information is the secret information; Encrypt the conversion information using a national secret algorithm to obtain a ciphertext code; The ciphertext code is written into a pixel matrix by a site scrambling algorithm to obtain a ciphertext image; The specific method of writing the ciphertext code into the pixel matrix through the site scrambling algorithm to obtain the ciphertext image is: Transform the original image to obtain a pixel matrix; Performing digital signature verification on the ciphertext code to obtain an information sequence; Determining an embedding point of the ciphertext code based on the information sequence; Embedding the ciphertext code into the pixel matrix according to the embedding point to obtain a ciphertext image; The site scrambling algorithm is used. The basic idea of ​​the algorithm is to first generate a pseudo-random sequence Seq1...Seqm through a pseudo-random generator, and then use two keywords with an increment of d in the Seq sequence to form two adjacent embedding points until the sequence position order is scrambled to generate a new two-dimensional sequence P, where m is the sequence length and d is the artificially set increment; The final embedding sequence F is determined by two remainder calculations to determine the specific position of the embedded two-dimensional sequence P. At the same time, a time seed factor is added to the remainder calculation to affect the irregularity of the embedding distribution.

2. A processing method based on digital watermark encryption and embedding as claimed in claim 1, characterized in that: The specific method of performing binary conversion on the secret information to obtain the converted information is: The secret information is converted into binary according to the ASCII rule to obtain the converted information.

3. A processing method based on digital watermark encryption and embedding as claimed in claim 2, characterized in that: The specific method of using the national secret algorithm to encrypt the conversion information to obtain the ciphertext code is: Encoding the conversion information using a coding technique to obtain a bit string of the conversion information; The bit string of the conversion information is digitally signed and encrypted using a national secret algorithm to obtain a ciphertext code.

4. A processing method based on digital watermark encryption and embedding as claimed in claim 3, characterized in that: The encoding technology is DNA encoding technology.

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