 Open Access
 Total Downloads : 612
 Authors : Keshav S. Kadam, Amar Deshmukh
 Paper ID : IJERTV5IS060670
 Volume & Issue : Volume 05, Issue 06 (June 2016)
 DOI : http://dx.doi.org/10.17577/IJERTV5IS060670
 Published (First Online): 27062016
 ISSN (Online) : 22780181
 Publisher Name : IJERT
 License: This work is licensed under a Creative Commons Attribution 4.0 International License
Video Frame Encryption Algorithm using AES
Keshav S. Kadam Prof. A. B. Deshmukh
EXTC Department EXTC Department
SKNCOE Vadgaon(bk) Pune SKNCOE Vadgaon(bk) Pune Maharashtra,India Maharashtra,India
AbstractThe data in some fields may include some sensitive in formation which should be protected from outside world while transmitting over network. Therefore security & privacy of sen sitive data is one of the important issues. Proposed methodology in this paper focuses on the security & privacy of a digital video. The proposed research includes three parts, that is first one is MPEG video compression, second one is video encryption and third one decryption. For encryption we used the AES algo rithm.AES algorithm is a block cipher & most used algorithms. Here, encryption of video streams is directly on the compressed domain Thus it preserves the compression & decompression time cycle.
Keywords AES, MPEG, Video encryption, Video Transmission,
I INTRODUCTION
A system for encrypting and decrypting information is a cryptosystem. Encryption usually involves an algorithm for combining the original data plaintext with one or more keys numbers or strings of characters known only to the transmitter and/or receiver. The resulting output of encryption is known as cipher text[1]. Cryptographic algorithms play an important role in security and resource conservation of real time applica tions. Cryptography is science in which information is trans mitted over network securely. In the cryptography there is a process in clientserver model. At server side encryption is done. Encryption is nothing but conversion of plaintext data into cipher text so that unauthorized user cannot access it. That encrypted data are transmitted over network to the client. At client side decryption is done in which cipher text is con verted in to the plain text. To protect data using cryptographic system there are two type of cryptographic algorithm one is symmetric key algorithm and second is asymmetric key algo rithm. In symmetric key algorithm same key is used at sender as well as receiver side [2][3].Data Encryption Standard (DES) and Advance Encryption Standard (AES) are the ex ample of symmetric key algorithm. While in asymmetric key algorithm two different key are used such as Rivert Shamir Adleman (RSA). For hardware as well as software implemen tation and high speed data transmission AES algorithm is more efficient. In wireless video communication system for high security hardware implementation is most useful [4].
MPEG (moving picture expert group) is most usable standard for video processing applications. Such In multimedia applica tion like Videoon Demand, video broadcast, multimedia mail and videoconferencing. Security of the video depends on the redundancy in the video as low as redundancy the video is more secure, As attacker get less clues about video. MPEG video is composed of a sequence of group of pictures (GOPs). Each GOP is composed of series of I, P, and B frames. I
frames are intraframe coded without any reference to other frames; P frames are predicatively coded using a previous I or P frames; and B frames are bidirectional interpolated from both the previous and following I and/or P frame. [5]. The security of MPEG video transmission can done by using two method by partial encryption or the entire MPEG bit stream. Algorithm which is use whole data is heavy weight algorithm while algorithm which uses partial or selective data is light weight algorithm. These both algorithms involve complex computations. Heavyweight algorithm displeases the problem and increases the time while lightweight algorithm provides sufficient security level and has an acceptable computation cost to MPEG video applications. Here we presented an effi cient MPEG video encryption algorithm for realtime video transmission by AES algorithm. Here we presented light weight selective encryption scheme for secure MPEG trans mission. It is based on Video Encryption Algorithm (VEA)
.VEA is lightweight selective encryption algorithm based on DES/IDEA. The security is significantly improved by adopt ing AES to encrypt data. This algorithm reduce computation time by processing by bounding the maximum number of bits selected [6].

RELATED WORK
For secure MPEG video encryption there are several video encryption algorithm is available which based in DES/IDEA. Every algorithm has its of them has its potency and weakness in terms of encryption ratio, security level, speed, and result ing stream size matrices. The well know video encryption algorithms are Naive algorithm, Pure Permutation Algorithm, Video Encryption Algorithm (VEA), ZigZag Permutation algorithm, and selective algorithm [7].The most straight forward method is to encrypt the entire MPEG stream by us ing standard encryption method such as DES or AES, This is called the Naive algorithm. In Naive algorithm MPEG bit stream is nothing but traditional text data and does not make use of the special any structures. This algorithm is the most secure algorithm but it is not applicable for video encryption because of its speed limit and data of video are big in size. as this algorithm is unable to fulfill the real time video encryp tion requirement so that it is not used for video encryption[8]. There is different method for selective algorithm which uses the features of MPEG layered structures. The basic selective algorithm uses only I frames for encryption as the value of P and B frames are nothing without knowing the corresponding I frames. But great portions of the video could be visible if p frames and b frames are not encrypted because some of the P and B frames may contain intracoded I blocks which may visible. If only I frames encrypted it save 3555% of encryp tiondecryption time. The size of encrypted stream does not change. One method of encryption is encrypt only MPEG
headers. But headers contain mostly standard information and a video stream is indexed by frame in order to perform syn chronization so that the beginning of each frame is known to attacker and this is not effective method [9].In ZigZag Permutation algorithm encryption is an integral part of the MPEG compression process. In which Instead of mapping 8×8 block to a 1×64 vector in zigzag order. This compression process uses a random permutation list to map the individual 8×8 block to a 1×64 vector. It cannot resist the known plaintext attack and is also fenceless to the cipher text only attack. The speed of processing is very fast and nearly the same as the MPEG encoding/decoding time .By this algorithm the size of encrypted MPEG stream will increase by a signifi cant factor [10]. Video Encryption Algorithm (VEA) in this algorithm secret key is used to randomly change the sign bits of all DCT coefficients of MPEG video. Propaganda to VEA is Realtime Video Encryption Algorithm (RVEA). For se lected sign bit encryption RVEA uses DES and VEA use only XOR operation. The security of RVEA is expressively im proved by adopting secret key cryptography algorithms to encrypt the data. RVEA restrict and reduce its computation time by bounding the maximum number of bits selected[11]. In Pure Permutation algorithm scrambling of byte stream is not part of permutation. The cardinality of the permutation key relies on the security level and the application requirement it can be varied as per requirement. The drawback of Pure Permutation algorithm is same as zigzag permutation algo rithm that it is also vulnerable to the known plaintext attack. Pure permutation algorithm doesnt have problem with speed as permutation is very fst. But Pure Permutation algorithm does not increase the stream size unless we change keys for each frame [12]
A. Advance Encryption Standard (AES)
AES is the standard encryption standard adopted by the NIST (National Institute of Standards and Technology) for securing data while communication. AES works on substitution permu tation network. AES has a fixed block size of 128 bits and a key size of 128, 192 or 256 bits. The entire algorithm is divid ed in to two sections, the Key expansion unit and the state processing unit. The number of rounds is 10 in case of 128 bits key (12 when key length is 192 bit and 14 when the key length is 256). For encryption, each round consists of the fol lowing four steps: 1) Substitute bytes, 2) Shift rows, 3) Mix columns, and 4) Add round key. The last step consists of XOR operation the output of the previous three steps with four words from the key schedule [13].
Below table give the comparative study of different video encryption algorithms.
Algorithm
Security
Speed
Size
Encryption Ratio
NaÃ¯ve
High
Slow
No change
100%
Pure Permutation
Low
Super fast
No change
100%
ZigZag Permuta tion
Very Low
Very fast
Big increase
100%
VEA
High
Fast
No change
50%
Selective
Moderate
Fast
Increase
1%100%
Algorithm
Security
Speed
Size
Encryption Ratio
NaÃ¯ve
High
Slow
No change
100%
Pure Permutation
Low
Super fast
No change
100%
ZigZag Permuta tion
Very Low
Very fast
Big increase
100%
VEA
High
Fast
No change
50%
Selective
Moderate
Fast
Increase
1%100%
TABLE 1.Comparison of different video encryption scheme
III PROPOSED METHODOLOGY
The block diagram of proposed method of real time video encryption is shown below.
Input Video
Video Frame
Video Compres sion
AES
Encryption
Input Video
Video Frame
Video Compres sion
AES
Encryption
Display
Display
Output Video
Video De compression
AES
Decryption
Output Video
Video De compression
AES
Decryption
Fig.1. Block diagram for MPEG video encryptionDecryption
As above diagram is includes three part video Compres sion, AES Encryption and AES Decryption each parts is ex plained below.

Video compression
Initially Input video taken from camera with predefined size 256*256 pixels. Sequence of video frame is given to compression. A Frame consist of YUV component where Y represent luminance and UV represent chrominance compo nents.1st this RGB frame convert into gray image. As the gray frame require less bit per pixel .This gray image convert into float image Float image used for DCT. So apply DCT on float image, by applying DCT to the float image get DCT co efficient value. this DCT coefficient value are I frame sign bit
.Take sign bit value of DCT coefficient for AES. Apply 128 bit AES algorithm on sign bit value of I frame. From I frame and D frame get motion vectors. Then take out sign value of motion vector.

AES Encryption
AES is standard chosen by National Institute of standard and Technology(NIST).This algorithm used block cipher of length 128,192 or 256 bits. Here we use 128 bit cipher. The input to the cipher is array of plaintext which is converted as state matrix. For each round, transformation round key is ex pansion of cipher key and never specified directly. Each round transformation is nothing but four different transfor mations such as AddRoundKey ByteSub, ShiftRow, and MixColumn,. The repeated application 10 rounds of transfor mation.
By the video compression we get the sign bit value of I frames and motion vectors this array of sign bit apply to the AES algorithm, Secret key is used to apply encryption. Input for cipher is 4*4 matrix of differential values..After 10 round of AES encryption cipher output is generated which is ac cessed by person who have secret key.

AES Decryption
Decryption algorithm is same at encryption and decryption side except at the the decryption time, inverse operations are performed. If user have secret key decryption process carried out. After decryption some of the coefficient are changed which will be propagated by Inverse DCT.
As compare to previous method this proposed method bounding the computation time by limiting maximum number of bit selection. General scheme for the real time video en cryption by selective encryption method.
Let P is plain text which produces bit streams C called cipher text , and Tk1 is invertible transformation for video stream. So
Cipher text will get by
? ? ?? ? ?? ? (1)
So the user who Have secret key k2 can only decrypt the vid eo by transformation
plemented by using Linux platform based Ubuntu operating system . For coding C++ programming language is used. For realtime operation communication encryption is done at the server side while decryption is done at the client side. Here only one system showed that is server side. It is impossible to include all the image frames here. Instead we just show one frame from video sequence to demonstrate our algorithm. The original frame is as shown in Figure 3.
? ?
? ?
? ? ? ? ? ? ? (2)
Decryption process is
? ? ? ?? ? ? ? ? ? ?? ? ? ? ? ? ??? ? ?? ?? ? ? (3)
? ? ? ?
Where k1 is called encryption key while k2 is decryption key.

Flow chart of proposed methodology
Proposed methodology can also be explained with help of flow chart given in figure 2. The flow chart show the all steps of systems .
Fig.2. Flow chart of proposed methodology

EXPERIMENTS
The following experiments were conducted on Real time MPEG video. A secure video communication system is im
Fig.3. Original frame
By Encrypting sign bits of all DCT coefficients of only I frame: The video image is incomprehensible. This is the me dium level of encryption. This is as shown in Figure 4.
Fig.4. Encryption of sign bit DC and AC coefficients.
Encrypting sign bits motion vector coefficients, the video im age is incomprehensible .motion vector taken from I frames and reference frame. Motion vector difference are taken out by motion vectors and P frame. By Appling AES on sign bits of motion vector difference we get higher level of encryption than the previous one. This is as shown in Figure 5.
So the figure 2 and 3 are the result of algorithm used for video encryption. Which is sufficient to provide security while real time video transmission. Decryption algorithm is also implemented on given set up and result of the decryption after applying secret key is shown in figure 6.
This result shows that the encryptiondecryption of the real time video is possible by using the given algorithm of encryption.
Fig.5. Encryption of sign bits of motion vectors
Fig.6.Decrypted video frame

CONCLUSION

Selective encryption algorithm selectively encrypts a frac tion of the whole video. Which is faster than encrypting the whole video with AES? As studying MPEG frame it s found that in typical MPEG1 videos signbits occupy less than 10% of the entire video bit stream. So that it can save up to 90% of encryption time as compared to the algorithm which encrypts entire video. This algorithm encrypts at most 128 bits, no mat ter what type of frame is used. This considerably reduces en cryption computations achieving satisfactory encryption re sults. A software implementation is fast enough to meet the realtime requirements of frame decoding. We believe that this can be used for secure real time video transmission applica tions.
this is software implementation. Farther it will be implement ed on Raspberry pi with ARM Processor.
ACKNOWLEDGMENT
Author would like to thanks to Prof. A. B. Deshmukh for his support as a project guide, cooperation and valuable sugges tions.
REFERENCES

M. Abomhara, Omar Zakaria, Othman O. Khalifa An Over view of Video Encryption TechniquesInternational Journal of Computer Theory and Engineering, Vol. 2, No. 1 February, 2010,17938201

Ms. Pooja Deshmukh, Ms. Vaishali Kolhe Modified AES Based Algorithm for MPEG Video Encryption ICICES2014 –
S.A.Engineering College, Chennai, Tamil Nadu, India

Keshav S. Kadam, Prof. A.B. Deshmukh, A Review on Video Encryption Technologies International Journal of Advanced Research in Computer and Communication Engineering Vol. 5,
Issue 3, March 2016

S.Hemalatha, V.Hemamalini, S.Manimozhi, B. Revathi, S. Sridevi Improved Crypto Analysis for Scrambling Digital Vid eo Using Secret Key International Journal of Innovative Re search in Computer and Communication Engineering Vol. 3, Is sue 3, March 2015

Le Gall, Didier, "MPEG: A Video Compression Standard for Multimedia Applications," Communications of the ACM, vol.34, no.4, pp. 4658, April 1991.

C. Shi, ShengYih Wang, and Bharat Bhargava,"MPEG Video Encryption in Realtime using secret key cryptography", Proc. Of PDPTA 99, Las Vegas, Nevada 1999.

C. Shi and Bhargava, "A Fast MPEG VideoEncryption Algo rithm", Proceedings of 6th ACM International Multimedia Con ference ,Bristol, UK, pp. 8188, September 1998.

S. Lian, Multimedia Content Encryption: Techniques and Ap plications.CRC, 2008.

I. Agi and L. Gong, "An Empirical Study of MPEG Video Transmission", Proceedings of the Internet Society Symposium on Network and Distributed Systems Security, pp. 137144. San Diego, CA, Feb. 1996.

Lei Tang, "Methods for Encrypting and Decrypting MPEG Vid eo Data Efficiently", Proceedings of ACM Multimedia 96, pp. 219229, Boston, MA, November 1996.

L. Qiao and K. Nahrstedt, A new algorithm for MPEG video encryption,"in Proceedings of The First International Confer ence on Imaging Science,Systems, and Technology (CISST'97), (Las Vegas, Nevada), pp. 21{29,July 1997.

Adam J. Slagell. KnownPlaintext Attack Against a Permutation Based VideoEncryption Algorithm. Available from http://eprint.iacr.org/2004/011.pdf .(Accessed on March 2, 2009)

Karthik Thiyagarajan Low Computational Overhead Video Encryption For Wireless Multimedia DevicesDalhousie Uni versity Halifax, Nova Scotia September 2014