CN108174207A - H.264 Entropy Coding Video Encryption Method Based on ZUC Algorithm - Google Patents

Abstract

The invention relates to an H.264 entropy coding video encryption method based on a ZUC algorithm, and belongs to the technical field of mobile communication. The method is as follows: in the CAVLC encoding process of H.264 video compression encoding, the ZUC algorithm is used to generate a random key stream, and the number of non-zero coefficients, the number of trailing coefficients, the sign of trailing coefficients, and the last non-zero coefficient The code stream encoded by the number of zeros and the number of zeros before each non-zero coefficient is XORed to obtain a new code stream, and then combined with the code stream encoded by the amplitude of other non-zero coefficients to realize encryption; The invention increases the number of encryption parameters and improves security; it is different from the plaintext obtained by the index, the complexity is low, and does not increase too much overhead; the ZUC algorithm is used, the calculation speed is fast, easy to implement, and can replace the existing There are foreign encryption algorithms used in the encryption method, which realizes the localization of the encryption algorithm.

Description

H.264 Entropy Coding Video Encryption Method Based on ZUC Algorithm

technical field

The invention belongs to the technical field of mobile communication, and relates to an H.264 entropy coding video encryption method based on a ZUC algorithm.

Background technique

①H.264 is a new generation of video coding standard. It focuses on high efficiency of compression and high reliability of transmission. Its excellent compression performance and good network performance make it widely used in various fields such as video real-time communication and network streaming media. . Entropy coding is a lossless compression coding method commonly used in H.264 and other video compression standards. ② There has been some research on the entropy coding encryption method. Wen et al proposed an encryption method that directly scrambles the code table or encrypts the code word sequence number. Tosun and Feng proposed an encryption method based on forward error correction coding. Li Xiaoju et al. proposed a scalable video encryption scheme based on CAVLC entropy coding, which improved the flexibility of the encryption algorithm.

③At present, the idea of encrypting H.264 entropy coding has been researched and realized to a certain extent, which can be mainly divided into encrypted password index and directly encrypted plaintext. For the encrypted password index, it is necessary to judge whether the encrypted index number falls in the valid area, which increases the calculation overhead; for the encrypted plaintext, there are few existing encryption schemes, and the difference between different schemes is mostly the change of the encryption algorithm , and the encryption algorithms are mostly foreign encryption algorithms, and there is no research on the application of national secret algorithms to the encryption process of H.264 entropy coding.

4. H.264 entropy encoding adopts the CAVLC method, according to the ZUC algorithm in the CAVLC encoding characteristics and the national secret algorithm, designing a new H.264 entropy encoding video encryption method based on the ZUC algorithm is the technical problem to be solved by the present invention.

Figure 1 is a flow chart of H.264 video compression encoding.

H.264 entropy coding provides two coding methods, which are Context Adaptive Variable Length Coding (CAVLC) and Context Adaptive Binary Arithmetic Coding (CABAC). Among them, CAVLC is easy to implement and simple to calculate. It is mainly used in communications with high real-time requirements such as video conferences, videophones, and wireless communications. All four grades of the H.264 codec standard include this coding method. CABAC has high coding efficiency, but the coding process is complicated, and it is mainly used in multimedia digital communication. The present invention only studies the widely used CAVLC, and the more complex CABAC is not considered for the time being.

In H.264 video compression encoding, there are six parameters in the CAVLC encoding process, which are the number of non-zero coefficients, the number of trailing coefficients, the sign of trailing coefficients, the amplitude of other non-zero coefficients, and the zero before the last non-zero coefficient The number of , the number of zeros before each non-zero coefficient. Each parameter has a related encoding code table, and the code stream is output according to the encoding index look-up table.

Contents of the invention

In view of this, the object of the present invention is to provide a kind of H.264 entropy coding video encryption method based on ZUC algorithm, will be to the number of non-zero coefficients, the number of trailing coefficients, the sign of trailing coefficients, the last non-zero coefficient before The five parameters of the number of zeros and the number of zeros before each non-zero coefficient are encrypted, and the encoding of the amplitude of the remaining non-zero coefficients involves prefix encoding and suffix encoding, which has a certain complexity, so this part is not encrypted.

To achieve the above object, the present invention provides the following technical solutions:

The H.264 entropy coding video encryption method based on the ZUC algorithm, the method is: in the CAVLC coding process of the H.264 video compression coding, the ZUC algorithm is used to generate a random key stream, and the number of non-zero coefficients and the number of trailing coefficients number, trailing coefficient sign, number of zeros before the last non-zero coefficient, and number of zeros before each non-zero coefficient. The code stream after value encoding is combined and output to realize encryption;

The specific steps are:

S1: During the CAVLC encoding process of H.264 video compression encoding, encode the parameters to obtain the original code stream;

S2: Generate and distribute the key stream according to the ZUC sequence cipher algorithm;

S3: Use the key stream to encrypt the original code stream encoded by important parameters to obtain the ciphertext code stream;

S4: Merge and output the ciphertext code stream and the unencrypted original code stream.

Further, the encoding of the parameters includes encoding the number of non-zero coefficients Total Coeffs, encoding the number of trailing coefficients Trailing Ones, encoding the symbols of trailing coefficients T1_Signs, encoding the remaining non-zero coefficient amplitude Levels, and encoding the last Total Zeros encoding of the number of zeros before non-zero coefficients and RunBefore encoding of the number of zeros before each non-zero coefficient.

Further, the original code stream after encoding the important parameters includes the number of non-zero coefficients, the number of trailing coefficients, the sign of trailing coefficients, the number of zeros before the last non-zero coefficient, and the number of zeros before each non-zero coefficient Count the code stream encoded by five parameters.

Further, the unencrypted original code stream is a code stream encoded with other non-zero coefficient amplitudes.

The beneficial effect of the present invention is that: the present invention is an H.264 entropy coding video encryption method based on the ZUC algorithm for the CAVLC method. In the CAVLC process of H.264 compression coding, the ZUC algorithm is used to generate the key stream, and the number of non-zero coefficients, the number of trailing coefficients, the sign of trailing coefficients, the number of zeros before the last non-zero coefficient, each The code stream encoded by the number of zeros before the non-zero coefficient is different or a new code stream is obtained, and then combined with the code stream encoded by the amplitude of the other non-zero coefficients to realize encryption.

(1) Compared with the existing encryption method, the present invention increases the quantity of encryption parameters and improves security; it is different or different from the plaintext obtained by the index, the complexity is low, and too much overhead is not increased; the ZUC algorithm is adopted, The calculation speed is fast, easy to implement, and the performance can replace the foreign encryption algorithm used in the existing encryption method, and the localization of the encryption algorithm is realized.

(2) In terms of security, the present invention has encrypted the number of non-zero coefficients, the number of trailing coefficients, the number of trailing coefficients, the number of zeros before the last non-zero coefficient, and the number of zeros before each non-zero coefficient . These parameters are mainly concentrated in low-frequency positions, occupy a large proportion in the block, and have no obvious statistical characteristics, so they are not easy to be deciphered. Compared with the existing scheme, only the trailing coefficient symbols, the amplitudes of the remaining non-zero coefficients, and the number of leading zeros of each non-zero coefficient are encrypted, which increases the amount of encrypted data and improves the security. The ZUC algorithm logically adopts a three-layer structure design, which greatly enhances the ability to resist attacks and has high security.

(3) In terms of complexity, compared with the method of encrypting the password index, the present invention adopts the method of directly encrypting the plaintext with the key stream, and the code stream and the key stream are XORed bit by bit, which saves the index number after encryption The time for judging whether it falls in the effective area is simple to operate, and has little impact on the time required for the entire encoding process, and the complexity is mainly determined by the sequence code. However, the key stream generated by the ZUC algorithm is 32 bits each time, the operation speed is fast, and the time required for key stream generation and distribution is less. Therefore, the calculation overhead of this method is very small.

(4) In terms of the choice of encryption algorithm, the ZUC algorithm is independently developed by our country. It has a simple structure, is easy to realize by software and hardware, and has a fast encryption and decryption speed. At the same time, due to some special designs adopted in the structure of ZUC, its anti-attack ability has been improved, and it has reliable high security performance and low complexity. It has been approved as the fourth-generation mobile communication encryption standard. Therefore, using the ZUC algorithm to encrypt video images can not only ensure the security well, but also realize the localization of encryption algorithms, and further promote the development and application of encryption algorithms in our country.

Description of drawings

In order to make the purpose, technical scheme and beneficial effect of the present invention clearer, the present invention provides the following drawings for illustration:

Fig. 1 is H.264 video compression coding flowchart;

Fig. 2 is a flow chart of CAVLC encoding;

Fig. 3 is the encryption flow chart of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The process of H.264 video compression coding is shown in Figure 1. The video is compressed and coded through intra-frame and inter-frame prediction, transformation, quantization, and entropy coding. Fig. 2 is a flow chart of CAVLC encoding; Fig. 3 is a flow chart of encryption in the present invention.

The CAVLC encoding process of H.264 mainly includes: (1) encoding the number of non-zero coefficients (TotalCoeffs) and the number of trailing coefficients (TrailingOnes); (2) encoding the trailing coefficient symbols (T1_Signs); (3 ) encode the remaining non-zero coefficient amplitudes (Levels); (4) encode the number of zeros before the last non-zero coefficient (TotalZeros); (5) encode the number of zeros before each non-zero coefficient (RunBefore ) to encode.

In the CAVLC encoding process of H.264 video compression encoding, the ZUC algorithm is used to generate a random key stream, which is related to the number of non-zero coefficients, the number of trailing coefficients, the sign of trailing coefficients, and the number of zeros before the last non-zero coefficient 1. Exclusive OR the code stream encoded by the number of zeros before each non-zero coefficient to obtain a new code stream, and then merge and output it with the code stream encoded by the magnitude of the other non-zero coefficients to realize encryption.

In step 2, the ZUC sequence cipher algorithm generates the key stream, which can be mainly divided into three steps: initial key loading, initialization phase and working phase. The main processing is the loading of the initial secret key. Under the control of the 128bit seed key and the 128bit initial vector, a 32bit key stream can be generated.

Distribute the key stream generated above into the code stream that needs to be encrypted, and use the key stream and the code stream to perform XOR operation to realize encryption.

This encryption method is illustrated with an example:

Suppose 4*4 blocks of data are:

0 0 -1 0 5 2 0 0 3 0 0 0 1 0 0 0

After data reordering, the Zigzag scanning coefficient input is: 0, 0, 5, 3, 2, -1, 0, 0, 0, 1, ...

After encoding, the code stream output by CAVLC encoding is obtained: 0000101100010010101010111. Let the key stream of encrypted block data be 0, 0, 1, 1,, 1, 0, 0, 1, ...

Encryption process:

It can be seen from the encryption process that for the number of non-zero coefficients (TotalCoeffs) and the number of trailing coefficients (TrailingOnes), the sign of trailing coefficients (T1_Signs), the number of zeros before the last non-zero coefficient (TotalZeros), each non-zero The original code stream encoded by the number of zeros before the coefficient (RunBefore) is subjected to an XOR operation to obtain a ciphertext code stream, which is combined and output with the code stream encoded by the remaining non-zero coefficient amplitudes (Levels) to realize encryption. The final ciphertext code stream is 0000101100010010010101110.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in terms of form and Various changes may be made in the details without departing from the scope of the invention defined by the claims.

Claims (4)

1. The H.264 entropy coding video encryption method based on the ZUC algorithm is characterized in that: the method is: in the CAVLC coding process of the H.264 video compression coding, the ZUC algorithm is used to generate a random key stream, and the number of non-zero coefficients number, the number of trailing coefficients, the sign of trailing coefficients, the number of zeros before the last non-zero coefficient, and the number of zeros before each non-zero coefficient. Merge and output code streams encoded with other non-zero coefficient amplitudes to realize encryption; The specific steps are: S1: During the CAVLC encoding process of H.264 video compression encoding, encode the parameters to obtain the original code stream; S2: Generate and distribute the key stream according to the ZUC sequence cipher algorithm; S3: Use the key stream to encrypt the original code stream encoded by important parameters to obtain the ciphertext code stream; S4: Merge and output the ciphertext code stream and the unencrypted original code stream. 2. the H.264 entropy coded video encryption method based on ZUC algorithm according to claim 1, is characterized in that: described parameter is encoded and comprises nonzero coefficient number Total Coeffs encoding, trailing coefficient number Trailing Ones encoding, encoding the trailing coefficient symbol T1_Signs, encoding the remaining non-zero coefficient amplitude Levels, encoding the number of zeros before the last non-zero coefficient Total Zeros and encoding the number of zeros before each non-zero coefficient Run Before . 3. the H.264 entropy coding video encryption method based on ZUC algorithm according to claim 1, is characterized in that: the original code stream after described important parameter encoding comprises non-zero coefficient number, trailing coefficient number, dragging The code stream encoded by five parameters including the sign of the tail coefficient, the number of zeros before the last non-zero coefficient, and the number of zeros before each non-zero coefficient. 4. The H.264 entropy coding video encryption method based on ZUC algorithm according to claim 1, characterized in that: the original code stream that is not encrypted is the code stream after encoding the remaining non-zero coefficient amplitudes.