The paper presents that encryption of compressed video bit streams and hiding privacy information to protect videos during transmission or cloud storage. Digital video sometimes needs to be stored and processed in an encrypted format to maintain security and privacy. Here, data hiding directly in the encrypted version of H.264/AVC video stream is approached, which includes the following three parts. By analyzing he property of H.264/AVC codec, the code words of intra prediction modes, the code words of motion vector differences, and the code words of residual coefficients are encrypted with stream ciphers. Then, a data hider may embed additional data in the encrypted domain by using wrapping technique, without knowing the original video content. The paper results shows that used methods provides better performance in terms of computation efficiency, high data security and video quality after decryption. The parameters such as RMSE, PSNR, CC are evaluated to measure its efficienc

Gengaiyan, Sanjay Kumar

Rajagopalan, Pradeep

English

Gyandhara International Academic Publication (GIAP): Journals

 International Journal of Students’ Research In Technology & Management 
Vol. 3(04), April 2015, ISSN 2321-2543, Pg. 343-345 
 
http://www.giapjournals.org/ijsrtm.html   343 
PRIVACY INFORMATION PROTECTION IN AN 
ENCRYPTED COMPRESSED H.264 VIDEO 
BITSTREAM 
Pradeep Rajagopalan, Sanjay Kumar Gengaiyan 
Department of Electrical and Electronic Engineering 
Easwari Engineering College, Anna University Chennai, Tamilnadu, India 
pradeepr28@gmail.com, gsk0395@gmail.com  
 
Abstract — The paper presents that encryption of compressed 
video bit streams and hiding privacy information to protect 
videos during transmission or cloud storage. Digital video 
sometimes needs to be stored and processed in an encrypted 
format to maintain security and privacy. Here, data hiding 
directly in the encrypted version of H.264/AVC video stream is 
approached, which includes the following three parts. By 
analyzing the property of H.264/AVC codec, the code words of 
intra prediction modes, the code words of motion vector 
differences, and the code words of residual coefficients are 
encrypted with stream ciphers. Then, a data hider may embed 
additional data in the encrypted domain by using wrapping 
technique, without knowing the original video content. The paper 
results shows that used methods provides better performance in 
terms of computation efficiency, high data security and video 
quality after decryption. The parameters such as RMSE, PSNR, 
CC are evaluated to measure its efficiency. 
Index terms –Privacy, H.264 Compression, chaos encryption, Bit 
wrapping based data hiding 
I. INTRODUCTION 
It is widely used in medical and military imagery for 
secret data communication. The system uses the h.264 
video encoding techniques for low bandwidth video 
transferring progress. In existing, pixel difference 
expansion based RDH is the spatial domain process to 
conceal secret text messages within a cover image. The 
data hiding involves histogram adjustment to reduce 
overflow and underflow error and adjacent pixels are 
subtracted to determine the differences values. Then 
difference will be either incremented or decremented based 
on message bits. This technique produces the spatial 
distortion leads to degrade an image quality and it is less 
compatible and complex one. This will be overcome by the 
method of least significant bit replacement algorithm. In 
Vacating room after encryption, the secret messages are 
concealed into encrypted domain by replacement of some 
pixel intensities. This spatial domain technique distorts an 
image quality wherever the secret message bits were 
hidden. With the consideration of these problems, the 
system proposes the reserve room approach with lifting 
wavelet transformation for preserving an image quality and 
improve the security of transmission. The technique lifting 
wavelet decomposes an image into frequency sub bands 
which contains approximation and detailed coefficients. 
The system will reserve the coefficients from detailed 
components which have texture, edges and region 
boundary. It is insensible region for human visual system. 
In addition with this approach, chaos crypto system, 
adaptive least significant bit replacement will be used for 
image encryption and message embedding. Data recovery 
is the reverse process of the encryption and embedding to 
get lossless extracted image and messages. The simulated 
result shows performance of the used methodologies in 
terms of metrics evaluation such as mean square error, 
peak signal to noise ratio and correlation coefficients.  
II. PROPOSED MODELS 
In this section, a novel scheme of data hiding in the 
encrypted version of H.264/AVC videos is presented, 
which includes three parts, i.e., H.264/AVC video 
encryption, data embedding and data extraction. The 
content owner encrypts the original H.264/AVC video 
stream using standard stream ciphers with encryption keys 
to produce an encrypted video stream. Then, the data-hider 
(e.g., a cloud server) can embed the additional data into the 
encrypted video stream by using bit wrapping method, 
without knowing the original video content. At the receiver 
end, the hidden data extraction can be accomplished either 
in encrypted or in decrypted version. 
After the compression process the encoded bit streams 
are going to encrypted using chaos encryption method. 
An H.264/AVC video encryption scheme with good 
performance including security, efficiency, and format 
compliance is proposed. By analysing the property of 
H.264/AVC codec, three sensitive parts (i.e., IPMs, MVDs, 
and residual coefficients) are encrypted with stream 
ciphers. The proposed encryption algorithm is performed 
not during H.264/AVC encoding but in the H.264/AVC 
compressed domain. In this case, the bit stream will be 
modified directly. 
 International Journal of Students’ Research In Technology & Management 
Vol. 3(04), April 2015, ISSN 2321-2543, Pg. 343-345 
 
http://www.giapjournals.org/ijsrtm.html   344 
 
III. SECRET DATA ENCRYPTION 
It is process of scrambling original information into 
unknown form using either symmetric or asymmetric key 
standard. Here it is one of the advanced encryption 
standard called chaos crypto system used. It encrypts the 
original image pixel values with encryption key value 
generated from chaotic sequence with threshold function 
by bitxor operation. 
 
Here logistic map is used for generation of chaotic map 
sequence. It is very useful to transmit the secret image 
through unsecure channel securely which prevents data 
hacking. The chaotic systems are defined on a complex or 
real number space called as boundary continuous space. 
The chaotic sequence will be defined by, Cn+1= U* 
Cn*(1-Cn) and encrypted pixel form defined by 
E = bitxor(P, Cn+1) 
IV. VIDEO FRAMES ENCRYPTION 
The compressed bit streams are encrypted using bitxor 
operation. Then the encrypted text was hidden in the 
encrypted compressed bit streams. The below diagram 
shows the video frames and compressed bit frames. 
 
Input frames 
 
Encrypted Frames 
V. BIT WRAPPING 
The process of bit wrapping method is to hide the 
encrypted secret data into the encrypted bit stream in the 
form of compression. The objective of steganography is a 
method of embedding additional information into the 
digital contents that is undetectable to listeners. We are 
investigating its embedding, detecting, and coding 
techniques. The idea behind the LSB algorithm is to insert 
the bits of the hidden message into the least significant bits 
of the pixels. As the application domain of embedding data 
in digital multimedia sources becomes broaden, several 
terms are used by various groups of researchers, including 
steganography, digital watermarking, and data hiding. The 
most frequently used steganography method is the 
technique of LSB substitution. In a gray-level image, every 
pixel consists of 8 bits. One pixel can hence display 
28=256 variations. The weighting configuration of an 8-bit 
number is illustrated. The basic concept of LSB 
substitution is to embed the confidential data at the right 
most bits (bits with the smallest weighting) so that the 
embedding procedure does not affect the original pixel 
value greatly. The mathematical representation for LSB 
method is:  x represents the i th pixel value of the stego-
image, i x represents that of the original cover-image, and i 
m represents the decimal value of the i th block in 
confidential data. The number of LSBs to be substituted is 
denoted as k. The extraction process is to copy the k-
rightmost bits directly. Mathematically the extracted 
message is represented as: 
Hence, a simple permutation of the extracted i m gives 
us the original confidential data. This method is easy and 
straightforward. However, when the capacity is greatly 
increased, the image quality decreases a lot and hence a 
suspected stego-image results. Furthermore, the 
confidential data might be easily stolen by simply 
extracting the k-rightmost bits directly. 
A 8-bit gray scale image matrix consisting m × n pixels 
and a secret message consisting of k bits. The first bit of 
message is embedded into the LSB of the first pixel and 
the second bit of message is embedded into the second 
pixel and so on. The resultant Stego-image which holds the 
secret message is also a 8-bit gray scale image and 
difference between the cover image and the Stego-image is 
 International Journal of Students’ Research In Technology & Management 
Vol. 3(04), April 2015, ISSN 2321-2543, Pg. 343-345 
 
http://www.giapjournals.org/ijsrtm.html   345 
not visually perceptible. The quality of the image, however 
degrades with the increase in number of LSBs. This hiding 
process will introduce the error between input and output 
image and it is determined by mean square error and Peak 
signal to noise ratio determines the image quality. 
Process Flow 
Embedding  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
VI. EXTRACTION 
 
 
 
 
 
 
 
VII. EXPERIMENTAL RESULTS 
The performance of used methodology will be evaluated 
with different amount of characters on natural images. 
Here the metrics such as Mean square Error, PSNR and 
Correlation measured. Correlation = 0.8963 and PSNR = 
43.78db. 
VIII. CONCLUSION 
The paper presented that protection of Video quality and 
hidden data during transmission based on approach of 
H.264 encoding and chaotic crypto system with bit 
wrapping based data concealment. Here, h.264 encoding 
method is used for compress the video frames effectively 
and chaos encryption was used as to protect image 
contents. This system was generated the stego video with 
less error under maximum data hiding capacity. It was 
better compatible approach and flexibility with better 
efficiency rather than prior methods  
REFERENCES 
[1] W. J. Lu, A. Varna, and M. Wu, “Secure video 
processing: Problems and challenges,” in Proc. IEEE 
Int. Conf. Acoust., Speech, Signal Processing, 
Prague, Czech Republic, May 2011, pp. 5856–5859. 
[2] B. Zhao, W. D. Kou, and H. Li, “Effective 
watermarking scheme in the encrypted domain for 
buyer-seller watermarking protocol,” Inf. Sci., vol. 
180, no. 23, pp. 4672–4684, 2010.  
[3] W. Puech, M. Chaumont, and O. Strauss, “A 
reversible data hiding method for encrypted images,” 
Proc. SPIE, vol. 6819, pp. 68191E-1–68191E-9, Jan. 
2008 
[4] X. P. Zhang, “Reversible data hiding in encrypted 
image,” IEEE Signal Process. Lett., vol. 18, no. 4, 
pp. 255–258, Apr. 2011. 
[5] W. Hong, T. S. Chen, and H. Y. Wu, “An improved 
reversible data hiding in encrypted images using side 
match,” IEEE Signal Process. Lett., vol. 19, no. 4, 
pp. 199–202, Apr. 2012. 
[6] X. P. Zhang, “Separable reversible data hiding in 
encrypted image,” IEEE Trans. Inf. Forensics 
Security, vol. 7, no. 2, pp. 826–832, Apr. 2012 
[7] K. D. Ma, W. M. Zhang, X. F. Zhao, N. Yu, and F. 
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2013. 
Input Video 
H.264 
Encoding 
Bitxor 
Coordinate 
Extraction 
Data Concealment 
Secret Data 
Encryption 
Decoding 
Stego Video 
Encrypted Stego 
Video 
Data 
Extraction 
Text 
Decryption 
Video 
Decryption 
Performance 
Analysis 


PRIVACY INFORMATION PROTECTION IN AN ENCRYPTED COMPRESSED H.264 VIDEO BITSTREAM

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PRIVACY INFORMATION PROTECTION IN AN ENCRYPTED COMPRESSED H.264 VIDEO BITSTREAM

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