【摘要】：視覺(jué)作為人類認(rèn)知世界的最直觀的方式。數(shù)字視頻緊隨著IT的浪潮,獲得非常迅速的發(fā)展。但是,一個(gè)完整的視頻是由個(gè)大量的數(shù)據(jù)信息組成,而視頻要想獲得實(shí)際的應(yīng)用,就必須對(duì)視頻進(jìn)行壓縮編碼,現(xiàn)如今發(fā)布的較為成熟的編碼標(biāo)準(zhǔn)是由ITU-T和ISO/IEC聯(lián)合發(fā)布的H.265/HEVC,它與前代H.264/AVC相比,能夠用比其少50%的碼率達(dá)到一樣的視頻質(zhì)量,它還擁有并行處理的設(shè)計(jì),其軟硬件實(shí)現(xiàn)將具有更為出色的實(shí)用性,因此它的出現(xiàn)將迅速取代H.264/AVC,并在視頻業(yè)務(wù)中受到廣泛追捧,但是它的出現(xiàn)并沒(méi)有改變視頻信息頻繁遭到惡意的攻擊和破壞的命運(yùn),因此基于H.265/HEVC的視頻加密技術(shù)也越來(lái)越受到關(guān)注。近年來(lái),研究學(xué)者們?cè)O(shè)計(jì)出了許多的加密算法,最早采用全加密的方法,雖然它的安全性能較高,但是,由于它巨大的計(jì)算工作量,使得它的實(shí)用性就變?nèi)趿�。后�?lái)又有基于DCT系數(shù)加密、熵編碼過(guò)程加密等與編解碼過(guò)程相結(jié)合的加密算法,這類算法雖然在一定程度上減少了加密的數(shù)據(jù)量,但對(duì)于保密的安全系數(shù)也相對(duì)降低了,隨著這類的研究的不斷深入,為了減少計(jì)算量的同時(shí)能擁有可觀的加密等級(jí),并且不影響壓縮效率,本文提出了一種全新的加密算法,其工作內(nèi)容和目的如下:對(duì)H.265的預(yù)測(cè)、變換、量化等部分的了解和分析,學(xué)習(xí)現(xiàn)有的一些加密算法,比較其優(yōu)劣和計(jì)算復(fù)雜度,在此基礎(chǔ)上,我們希望設(shè)計(jì)出一種能實(shí)現(xiàn)視頻的部分加密的算法,同時(shí)在對(duì)密鑰未知的情況下使得圖像在解碼端能夠被重建,但是重建后的圖像質(zhì)量有所下降,使其不能獲得原始的信息,從而達(dá)到加密目的。相比于現(xiàn)在已經(jīng)有的在熵編碼階段或者比特流中加密的加密方法,我們?cè)谖恼轮刑岢隽嗽谧儞Q階段進(jìn)行加密:根據(jù)改變蝶形中第二階段的旋轉(zhuǎn)角度,從而設(shè)計(jì)出一系列變換矩陣,并通過(guò)仿真驗(yàn)證這些矩陣是否會(huì)影響編碼效率,然后通過(guò)RC4算法隨機(jī)產(chǎn)生的密鑰對(duì)一系列新的變換矩陣進(jìn)行選擇,從而替代原始的DCT,因此在解碼端對(duì)密鑰未知的情況下,對(duì)于采用的具體哪一個(gè)變換矩陣就是未知的,從而實(shí)現(xiàn)視頻的部分加密的目的。文章最后將我們的算法應(yīng)用到具體的視頻序列中去,然后針對(duì)密鑰信息掌握的不同程度來(lái)分析解碼端的視頻質(zhì)量,對(duì)加密等級(jí)進(jìn)行評(píng)估。
[Abstract]:Vision is the most intuitive way for human beings to perceive the world. Digital video is following the tide of IT, obtain very rapid development. However, a complete video is composed of a large amount of data information, and if the video is to be used in practice, it must be compressed and encoded. The more mature coding standard released today is H.265 / HEVC, released jointly by ITU-T and ISO/IEC, which can achieve the same video quality with 50 percent less bit-rate than the previous H.264/AVC. It also has the design of parallel processing, and its hardware and software implementation will be more practical, so it will quickly replace H.264% AVC, and be popular in the video business. However, its appearance has not changed the fate that video information is frequently attacked and destroyed by malicious attacks. Therefore, video encryption technology based on H.265/HEVC has been paid more and more attention. In recent years, researchers have designed many encryption algorithms, the earliest full encryption method, although its security performance is high, but because of its huge computing workload, it becomes less practical. Then there are encryption algorithms based on DCT coefficient encryption, entropy encoding process encryption and encoding and decoding process. Although these algorithms reduce the amount of encrypted data to a certain extent, the security factor for security is also relatively reduced. With the development of this kind of research, a new encryption algorithm is proposed in this paper in order to reduce the amount of computation and have a considerable encryption level without affecting the compression efficiency. Its contents and purposes are as follows: understanding and analyzing the prediction, transformation, quantization and other parts of H.265, learning some existing encryption algorithms, comparing their advantages and disadvantages and computational complexity, on this basis, We hope to design a partial encryption algorithm to realize the video, and at the same time, we can reconstruct the image at the decoding end without knowing the key, but the quality of the reconstructed image is degraded, which makes it unable to obtain the original information. In order to achieve the purpose of encryption. Compared with the existing encryption methods used in entropy encoding or bitstream encryption, we propose to encrypt in the transformation phase by changing the rotation angle of the second stage in the butterfly. A series of transformation matrices are designed and verified by simulation, and then a series of new transformation matrices are selected by random key generated by RC4 algorithm to replace the original DCT,. Therefore, when the key is unknown at the decoding end, which transformation matrix is unknown, so that the purpose of partial encryption of video can be realized. Finally, our algorithm is applied to the specific video sequence, and then the video quality of the decoder is analyzed according to the different degree of key information, and the encryption level is evaluated.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN919.81

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 ;Parallel processing architecture of H.264 adaptive deblocking filters[J];Journal of Zhejiang University(Science A:An International Applied Physics & Engineering Journal);2009年08期

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本文編號(hào)：2419584