CN117333346A - Method and system for embedding and tracing image watermark - Google Patents

Abstract

The invention discloses a method and a system for embedding and tracing an image watermark, comprising the following steps: and (3) key generation: generating a plurality of pairs of asymmetric keys, including a plurality of pairs of public keys and private keys; multiple watermarks are generated, a random number generator is used for generating a plurality of watermark information, and each watermark information can be independently embedded into an image; watermark information encryption and signature: encrypting each piece of watermark information to be embedded respectively, and encrypting the watermark information by using a public key to obtain an encrypted watermark; carrying out digital signature on the encrypted watermark by using a private key to obtain a digital signature result; image watermark embedding: embedding the encrypted watermark and the digital signature result into a frequency domain in an image, wherein each graphic watermark is embedded in a scattered way; the method and the system for embedding and tracing the image watermark adopt a multiple watermark technology, even if part of watermark information is deleted, the rest of watermark information can be extracted, and meanwhile, the method and the system adopt scattered embedding, have higher concealment and can be carried out.

Description

Method and system for embedding and tracing image watermark

Technical Field

The invention relates to a method and a system for embedding and tracing an image watermark.

Background

With the continuous development of the internet and multimedia technology, copyright protection of digital images is receiving increasing attention. Many businesses and individuals will watermark images in order to protect their own rights. However, the existing watermarking technology has some problems such as poor visual visibility, easy occlusion of picture content, easy tampering or copying of the watermark, and the like. These problems lead to the misuse of many images on the internet that are not licensed by the copyright owner, who cannot be protected by their legal rights.

Meanwhile, as digital image piracy becomes more and more common, digital watermarking technology is also continuously developed. Currently, digital watermarking technology is mainly applied to the fields of copyright protection and piracy tracking, and by embedding and extracting digital watermarks, unauthorized image copies can be tracked, and finally the responsibility of infringers can be pursued.

The existing method for embedding and tracing the watermark of the image has the defects that the watermark information is decrypted and tampered by an unauthorized user, the robustness and the reliability are not strong, the watermark information is easy to lose efficacy once tampered, and the visual quality of the image is influenced.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method which can effectively prevent watermark information from being decrypted and tampered, adopts a multiple watermark technology, can extract other watermark information even if part of the watermark information is deleted, and simultaneously adopts scattered embedding, concealment and stronger image watermark embedding and tracing.

The technical scheme adopted for solving the technical problems is as follows:

a method of image watermark embedding, comprising the steps of:

and (3) key generation: generating a plurality of pairs of asymmetric keys, including a plurality of pairs of public keys and private keys;

multiple watermarks are generated, a random number generator is used for generating a plurality of watermark information, and each watermark information can be independently embedded into an image;

watermark information encryption and signature: encrypting each piece of watermark information to be embedded respectively, and encrypting the watermark information by using a public key to obtain an encrypted watermark; carrying out digital signature on the encrypted watermark by using a private key to obtain a digital signature result;

image watermark embedding: and embedding the encrypted watermark and the digital signature result into the frequency domain of the image, wherein each graphic watermark is embedded in a scattered way.

Preferably, the method for generating the key comprises the following steps:

an OpenSSL command line tool is used for generating an RSA key pair, and a plurality of private key files and a plurality of public key files are generated.

Preferably, the method for encrypting and signing the watermark information comprises the following steps:

encrypting the watermark information by using the public key to obtain an encrypted watermark;

preparing watermark information to be encrypted, which can be any text or binary data;

using an OpenSSL's rsault command to complete encryption operation, encrypting the watermark information file by using a public key file, and storing the encrypted result in the file;

and carrying out digital signature on the encrypted information file by using an OpenSSL rsault command, and storing a digital signature result in the file.

Preferably, the method for embedding the image watermark comprises the following steps:

preparing an original image file containing watermark information;

converting the original image into a frequency domain representation using a discrete fourier transform;

embedding the encrypted watermark and the digital signature result into the frequency domain image by using low-frequency embedding;

performing inverse transformation on the embedded frequency domain image, and converting the frequency domain image back to a time domain;

and storing the image file with the embedded watermark in a database.

Another technical problem to be solved by the present invention is to provide a method for tracing an image watermark, which includes the following steps:

acquiring an image to be traced, and ensuring that the image has original encrypted watermark and digital signature information;

performing Fourier transform or wavelet transform on the acquired image, and converting the acquired image into a frequency domain representation;

positioning and extracting embedded encrypted watermark information in the frequency domain image;

performing inverse transformation on the extracted frequency domain image, and recovering the frequency domain image into a time domain representation;

extracting embedded encryption watermark information and a digital signature result from the image after the inverse transformation;

verifying the extracted digital signature by using the public key, and if the verification is passed, indicating that the watermark information of the image is not tampered; if the verification fails, the image is possibly tampered;

decrypting the extracted encrypted watermark by using a private key to obtain a plurality of original watermark information;

and according to the decrypted watermark information, tracing and searching in the database, and judging whether any watermark information is matched to be a tracing image.

Another technical problem to be solved by the present invention is to provide an image watermark embedding system, comprising:

a key generation module for generating a plurality of pairs of asymmetric keys including a public key and a private key, the public key and private key pairs to be used for encrypting and signing watermark information;

the watermark information encryption and signature module is used for encrypting and digitally signing the watermark information to be embedded;

and the image watermark embedding module is used for embedding the encrypted watermark and the digital signature result into the frequency domain of the image.

Preferably, the watermark information encryption and signature module comprises:

the watermark information encryption module encrypts watermark information by using a public key encryption algorithm;

and the digital signature module is used for carrying out digital signature operation on the encrypted watermark information by using the private key.

Another technical problem to be solved by the present invention is to provide a system for tracing an image watermark, comprising:

the image acquisition module is used for acquiring images to be traced;

the transformation module is used for carrying out Fourier transformation on the acquired image and converting the acquired image into a frequency domain representation;

the watermark extraction module is used for positioning and extracting embedded encrypted watermark information in the frequency domain image;

the inverse transformation module is used for carrying out inverse transformation on the extracted frequency domain image and recovering the frequency domain image into a time domain representation;

the digital signature verification module verifies the extracted digital signature by using the public key;

the watermark decrypting module decrypts the extracted encrypted watermark by using the private key to obtain original watermark information;

and the database tracing module is used for tracing and searching in the database according to the decrypted watermark information.

The beneficial effects of the invention are as follows:

the scheme encrypts watermark information by means of asymmetric key encryption. Compared with the traditional symmetric key encryption, the asymmetric key encryption is safer and more reliable, and can effectively prevent watermark information from being decrypted and tampered by unauthorized users; the scheme is implemented by generating a plurality of watermark information and embedding them into an image independently. Compared with a single watermark embedding method, the multiple watermark embedding can improve the robustness and reliability of the watermark, and even if part of watermark information is tampered or deleted, other watermark information can still be extracted; the scheme performs digital signature on the encrypted watermark to ensure the integrity and authenticity of the watermark. The digital signature can prevent watermark information from being tampered or replaced, and can be used for tracking piracy and identifying and verifying legal watermark information; the scheme adopts a scattered embedding mode to embed watermark information into the frequency domain of an image. Compared with a centralized embedding method, the method has the advantages that watermark information can be better hidden by scattered embedding, the influence of the watermark on the visual quality of the image is reduced, and the concealment and the visibility of the watermark are improved.

Detailed Description

The present invention will be further described with reference to specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the present invention and practice it.

Examples

A method of image watermark embedding, comprising the steps of:

and (3) key generation: generating a plurality of pairs of asymmetric keys, including a plurality of pairs of public keys and private keys;

multiple watermarks are generated, a random number generator is used for generating a plurality of watermark information, and each watermark information can be independently embedded into an image;

watermark information encryption and signature: encrypting each piece of watermark information to be embedded respectively, and encrypting the watermark information by using a public key to obtain an encrypted watermark; carrying out digital signature on the encrypted watermark by using a private key to obtain a digital signature result;

image watermark embedding: and embedding the encrypted watermark and the digital signature result into the frequency domain of the image, wherein each graphic watermark is embedded in a scattered way.

And (3) key generation: a plurality of pairs of asymmetric keys, including a plurality of pairs of public and private keys, are generated using a cryptographic algorithm. The public key is used to encrypt the watermark information and the private key is used for digital signature.

Multiple watermark generation: a plurality of watermark information is generated using a random number generator, each of which may be embedded independently in the image. The generated watermark may be text, an icon, or other form of information.

Watermark information encryption and signature: and encrypting each piece of watermark information to be embedded respectively. And encrypting the watermark information by using the public key to obtain the encrypted watermark. And then, carrying out digital signature on the encrypted watermark by using a private key to obtain a digital signature result so as to ensure the integrity and authenticity of the watermark.

Image watermark embedding: the encrypted watermark and digital signature result are embedded into the frequency domain in the image. The watermark information can be embedded in different frequency domain components of the image in a scattered embedding way so as to improve the robustness and concealment of the watermark.

The following points need to be noted in the implementation process:

a. security of keys: the generated key needs to be kept well, ensuring that only authorized persons can access the private key to prevent unauthorized tampering and decryption.

b. Selection of encryption algorithm and digital signature algorithm: and a safe and reliable encryption algorithm and a digital signature algorithm are selected, so that the safety and reliability of the encryption and signature process are ensured.

c. The embedding mode of watermark information: the proper embedding mode is selected according to specific conditions, and the technical means such as scattered embedding, spread spectrum embedding and the like can be considered so as to consider the concealment and the visibility of the watermark.

d. Watermark extraction and verification: after receiving the watermarked image, the image receiver needs to perform watermark extraction and verification to confirm the integrity and authenticity of the watermark.

The key generation method comprises the following steps:

an OpenSSL command line tool is used for generating an RSA key pair, and a plurality of private key files and a plurality of public key files are generated.

OpenSSL is a widely used and validated cryptographic library that provides reliable encryption and signature algorithms. The generated RSA key pair can meet the security requirement, and the confidentiality of the private key and the public key are ensured; openSSL is an open source tool maintained and developed by global cryptology experts, and code is audited and tested, thus having high reliability. The generated key pair can be widely accepted and used and verified in various application scenarios; openSSL supports the generation of RSA key pairs with different lengths, and the key pairs meeting specific security requirements can be generated according to requirements. Meanwhile, openSSL also supports the export and import of keys, so that the generated key pairs can be conveniently used in different systems and environments; openSSL provides a set of command line tools, is simple and convenient to use, and is rapid and efficient in the process of generating an RSA key pair. The key pairs with the required number can be generated through simple commands, and the key pair generation efficiency is improved.

The method for encrypting and signing the watermark information comprises the following steps:

encrypting the watermark information by using the public key to obtain an encrypted watermark;

preparing watermark information to be encrypted, which can be any text or binary data;

using an OpenSSL's rsault command to complete encryption operation, encrypting the watermark information file by using a public key file, and storing the encrypted result in the file;

and carrying out digital signature on the encrypted information file by using an OpenSSL rsault command, and storing a digital signature result in the file.

By encrypting the watermark information using the public key, it is ensured that only the person holding the private key can decrypt and view the watermark content. This protects sensitive information from unauthorized access; by digitally signing the encrypted watermark information, the integrity and authenticity of the watermark can be verified. If the watermark data is tampered with during transmission or storage, the digital signature will be invalid, so that the situation of tampered data can be found.

Each generated watermark is unique, and each watermark can be ensured to be unique through digital signature. Thus, the malicious user can be prevented from copying a watermark for multiple times to deception or abuse; the public key used in the encryption and signing process is public and therefore can be traced back to the owner of the watermark information. If misuse or illegal action occurs, the relevant responsible person can be found through the public key.

The method for embedding the image watermark comprises the following steps:

preparing an original image file containing watermark information;

converting the original image into a frequency domain representation using a discrete fourier transform;

embedding the encrypted watermark and the digital signature result into the frequency domain image by using low-frequency embedding;

performing inverse transformation on the embedded frequency domain image, and converting the frequency domain image back to a time domain;

and storing the image file with the embedded watermark in a database.

By embedding the watermark information in the image of the frequency domain representation, concealment of the watermark can be achieved. The watermark is invisible in the time domain, and the existence of the watermark can be identified only by a specific processing method, so that the security and the authentication of the watermark are protected; the frequency domain embedding can improve the robustness of the watermark, so that the watermark has certain resistance to common image processing attacks (such as clipping, scaling, rotation and the like). Even if the image is modified to a certain extent, the embedded watermark can still be extracted, so that the reliability and accuracy of the watermark are ensured.

By embedding the watermark in the low frequency part of the image, which is the low frequency embedding, the capacity of the watermark and the image quality can be balanced to some extent. The low-frequency embedding can not obviously influence the visual perception quality of the image, and can embed more watermark information; the frequency domain embedding scheme can carry out inverse transformation on the image in the watermark extraction process, and restore the frequency domain image after the watermark is embedded into the original image. Thus, the integrity and the reducibility of the watermark content can be ensured, and the accuracy in watermark extraction is ensured.

A method of image watermark tracing, comprising the steps of:

acquiring an image to be traced, and ensuring that the image has original encrypted watermark and digital signature information;

performing Fourier transform or wavelet transform on the acquired image, and converting the acquired image into a frequency domain representation;

positioning and extracting embedded encrypted watermark information in the frequency domain image;

performing inverse transformation on the extracted frequency domain image, and recovering the frequency domain image into a time domain representation;

extracting embedded encryption watermark information and a digital signature result from the image after the inverse transformation;

verifying the extracted digital signature by using the public key, and if the verification is passed, indicating that the watermark information of the image is not tampered; if the verification fails, the image is possibly tampered;

decrypting the extracted encrypted watermark by using a private key to obtain a plurality of original watermark information;

and according to the decrypted watermark information, tracing and searching in the database, and judging whether any watermark information is matched to be a tracing image.

By using an encrypted watermark and a digital signature, the security of the embedded watermark information can be ensured. The digital signature verification process can detect whether the image is tampered or not, and the integrity and the authenticity of the image are ensured; by decrypting and extracting the embedded encrypted watermark information, the original watermark information may be obtained. Such watermark information may be used for trace back and retrieval in a database to verify the origin and authenticity of the image. Any watermark information matching can be identified as tracing images, so that tracing and tracing of the images are realized.

The original time domain image can be restored by extracting and inversely transforming the frequency domain image. Even if the image is tampered to a certain extent, the embedded watermark information can be extracted, and tracing and judging can be performed. The method enhances the attack resistance of the image watermarking scheme and protects the reliability of watermark information; by matching the decrypted watermark information with watermark information in a database, the tracing and searching of the image can be realized. This helps to confirm the origin, authenticity and legitimacy of the image, providing an effective tool to deal with problems such as image theft and abuse.

An image watermark embedding system, comprising:

a key generation module for generating a plurality of pairs of asymmetric keys including a public key and a private key, the public key and private key pairs to be used for encrypting and signing watermark information;

the watermark information encryption and signature module is used for encrypting and digitally signing the watermark information to be embedded;

and the image watermark embedding module is used for embedding the encrypted watermark and the digital signature result into the frequency domain of the image.

The watermark information may be encrypted and digitally signed using the public key and the private key generated by the asymmetric key pair. Encryption protection ensures that watermark information is not easily decrypted and tampered with, while digital signatures can verify the integrity and authenticity of watermark information. Thus, the watermark information can be effectively prevented from being forged and tampered, and the anti-counterfeiting capability of the image is improved; the encrypted watermark and the digital signature are embedded into the frequency domain of the image, so that the watermark information can be hidden and the image quality can be ensured. When the image to which the watermark belongs needs to be traced, the tracing and searching of the image can be realized by extracting the watermark information in the frequency domain and decrypting and verifying the watermark information. This helps to confirm the origin and authenticity of the image, providing an effective traceability means.

The image watermark embedding system can encrypt the watermark information, and only people with corresponding private keys can decrypt and extract the watermark information. Thus, the privacy of watermark information can be protected, unauthorized persons are prevented from acquiring and abusing the watermark information, and personal privacy and copyright are protected; the image watermark embedding system is based on asymmetric key encryption and digital signature technology, and the technology is widely accepted and has higher security and reliability after long-term research and application. The system adopts a frequency domain embedding technology, can realize the hiding and the extraction of watermark information while guaranteeing the image quality, and has better technical stability.

The watermark information encryption and signature module comprises:

the watermark information encryption module encrypts watermark information by using a public key encryption algorithm;

and the digital signature module is used for carrying out digital signature operation on the encrypted watermark information by using the private key.

A system for image watermark tracing, comprising:

the image acquisition module is used for acquiring images to be traced;

the transformation module is used for carrying out Fourier transformation on the acquired image and converting the acquired image into a frequency domain representation;

the watermark extraction module is used for positioning and extracting embedded encrypted watermark information in the frequency domain image;

the inverse transformation module is used for carrying out inverse transformation on the extracted frequency domain image and recovering the frequency domain image into a time domain representation;

the digital signature verification module verifies the extracted digital signature by using the public key;

the watermark decrypting module decrypts the extracted encrypted watermark by using the private key to obtain original watermark information;

and the database tracing module is used for tracing and searching in the database according to the decrypted watermark information.

The system can realize the sensitivity and high-efficiency extraction of the frequency domain in the image based on the front mathematical theory such as Fourier transformation. When the encrypted watermark information is extracted, the integrity and the authenticity of the watermark information are ensured by using a public key to carry out digital signature verification and a private key to carry out decryption operation. Thus, the reliability and the traceability of the system can be improved; the image watermark tracing system is based on advanced algorithm and technology, and can realize rapid extraction and decoding of the encrypted watermark information, thereby realizing rapid retrieval and tracing of images. Compared with the traditional image recognition and comparison method, the system has higher efficiency and accuracy.

The image watermark tracing system protects watermark information by using encryption technology, and ensures that the watermark information is not acquired and abused by unauthorized persons. Meanwhile, in the database tracing module, a safe privacy protection strategy is adopted by the system, so that the privacy and the safety of user data are maintained; the image watermark tracing system is a safety protection means based on advanced technology, provides a novel image tracing and anti-counterfeiting means, and has innovation and technological content.

The beneficial effects of the invention are as follows:

the scheme encrypts watermark information by means of asymmetric key encryption. Compared with the traditional symmetric key encryption, the asymmetric key encryption is safer and more reliable, and can effectively prevent watermark information from being decrypted and tampered by unauthorized users; the scheme is implemented by generating a plurality of watermark information and embedding them into an image independently. Compared with a single watermark embedding method, the multiple watermark embedding can improve the robustness and reliability of the watermark, and even if part of watermark information is tampered or deleted, other watermark information can still be extracted; the scheme performs digital signature on the encrypted watermark to ensure the integrity and authenticity of the watermark. The digital signature can prevent watermark information from being tampered or replaced, and can be used for tracking piracy and identifying and verifying legal watermark information; the scheme adopts a scattered embedding mode to embed watermark information into the frequency domain of an image. Compared with a centralized embedding method, the method has the advantages that watermark information can be better hidden by scattered embedding, the influence of the watermark on the visual quality of the image is reduced, and the concealment and the visibility of the watermark are improved.

The above-mentioned embodiments of the present invention are not intended to limit the scope of the present invention, and the embodiments of the present invention are not limited thereto, and all kinds of modifications, substitutions or alterations made to the above-mentioned structures of the present invention according to the above-mentioned general knowledge and conventional means of the art without departing from the basic technical ideas of the present invention shall fall within the scope of the present invention.

Claims (8)

1. A method of image watermark embedding, comprising the steps of:

and (3) key generation: generating a plurality of pairs of asymmetric keys, including a plurality of pairs of public keys and private keys;

multiple watermarks are generated, a random number generator is used for generating a plurality of watermark information, and each watermark information can be independently embedded into an image;

watermark information encryption and signature: encrypting each piece of watermark information to be embedded respectively, and encrypting the watermark information by using a public key to obtain an encrypted watermark; carrying out digital signature on the encrypted watermark by using a private key to obtain a digital signature result;

image watermark embedding: and embedding the encrypted watermark and the digital signature result into the frequency domain of the image, wherein each graphic watermark is embedded in a scattered way.

2. A method of image watermark embedding according to claim 1, wherein the method of key generation is:

an OpenSSL command line tool is used for generating an RSA key pair, and a plurality of private key files and a plurality of public key files are generated.

3. A method of image watermark embedding according to claim 2, wherein the method of watermark information encryption and signing is:

encrypting the watermark information by using the public key to obtain an encrypted watermark;

preparing watermark information to be encrypted, which can be any text or binary data;

using an OpenSSL's rsault command to complete encryption operation, encrypting the watermark information file by using a public key file, and storing the encrypted result in the file;

and carrying out digital signature on the encrypted information file by using an OpenSSL rsault command, and storing a digital signature result in the file.

4. A method of image watermark embedding according to claim 3, wherein the method of image watermark embedding is:

preparing an original image file containing watermark information;

converting the original image into a frequency domain representation using a discrete fourier transform;

embedding the encrypted watermark and the digital signature result into the frequency domain image by using low-frequency embedding;

performing inverse transformation on the embedded frequency domain image, and converting the frequency domain image back to a time domain;

and storing the image file with the embedded watermark in a database.

5. The image watermark tracing method is characterized by comprising the following steps of:

acquiring an image to be traced, and ensuring that the image has original encrypted watermark and digital signature information;

performing Fourier transform or wavelet transform on the acquired image, and converting the acquired image into a frequency domain representation;

positioning and extracting embedded encrypted watermark information in the frequency domain image;

performing inverse transformation on the extracted frequency domain image, and recovering the frequency domain image into a time domain representation;

extracting embedded encryption watermark information and a digital signature result from the image after the inverse transformation;

verifying the extracted digital signature by using the public key, and if the verification is passed, indicating that the watermark information of the image is not tampered; if the verification fails, the image is possibly tampered;

decrypting the extracted encrypted watermark by using a private key to obtain a plurality of original watermark information;

and according to the decrypted watermark information, tracing and searching in the database, and judging whether any watermark information is matched to be a tracing image.

6. An image watermark embedding system, comprising:

a key generation module for generating a plurality of pairs of asymmetric keys including a public key and a private key, the public key and private key pairs to be used for encrypting and signing watermark information;

the watermark information encryption and signature module is used for encrypting and digitally signing the watermark information to be embedded;

and the image watermark embedding module is used for embedding the encrypted watermark and the digital signature result into the frequency domain of the image.

7. The image watermark embedding system as claimed in claim 6, wherein the watermark information encryption and signature module comprises:

the watermark information encryption module encrypts watermark information by using a public key encryption algorithm;

and the digital signature module is used for carrying out digital signature operation on the encrypted watermark information by using the private key.

8. A system for image watermark tracing, comprising:

the image acquisition module is used for acquiring images to be traced;

the transformation module is used for carrying out Fourier transformation on the acquired image and converting the acquired image into a frequency domain representation;

the watermark extraction module is used for positioning and extracting embedded encrypted watermark information in the frequency domain image;

the inverse transformation module is used for carrying out inverse transformation on the extracted frequency domain image and recovering the frequency domain image into a time domain representation;

the digital signature verification module verifies the extracted digital signature by using the public key;

the watermark decrypting module decrypts the extracted encrypted watermark by using the private key to obtain original watermark information;

and the database tracing module is used for tracing and searching in the database according to the decrypted watermark information.