Abstract— process through which a message is converted into

Abstract— This paper gives
a brief overview of using SHA (Secure Hashing Algorithm) for Video files. Recently, the
most widely used hash function has been the Secure Hash Algorithm, because
virtually every other widely used hash function have been found to have substantial
cryptanalytic weakne . SHA was more or less the last remaining standardized
hash algorithm by 2005 . SHA (Secure Hashing Algorithm) originally developed by
National Security Agency (NSA) and later handed over to National Institute of
Standard and Technology (NIST) are a way to ensure information security. They are typically used in digital signature
and in connections with secure websites.  Data that is run through a hash algorithm  produces shorter string of bits; this string
acts as a kind of digest of the data. Any changes to the
data changes the bit string resulting string therefore acts as a finger
print of the data, guaranteeing that no one has tempered with it.  However having algorithm like SHA for only
text and images is a waste it’s potential.

Keywords—Message
digest; Hash function; Video security

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I.         
 Introduction

Secure Hashing Algorithm is a method or
process through which a message is converted into smaller size that is it is
compressed it uses message digest algorithm for converting the variable length
data into fixed length data and then it creates a hash value of the data of 16
bit length thus when the data file is opened it will require the hash value or
figure print to open the data file. Image hash function have become an important field of research for past
few years earlier hash functions was used to provide security for text in SSL
certificates, Image hash functions map images to short binary strings in order
to facilitate comparisons and researches this functions have property that two
images which look same will have same hash value with small bit-level
differences 4. Video file in regard to this paper
for the receiver to view the video file. Video is a collection of data or
information in itself for compressing it and then creating a hash value or
figure print of it and maintain its quality at the same time is a difficult
task which is what this algorithm is trying to achieve.

                                                                                                                                                       
II.        
Literature Survey

A cryptographic hash function takes a message of
arbitrary length and creates a message digest of fixed length 1. A hash function needs to create a fixed size digest out
of a variable-size message. Multi-collisions in Iterated Hash Functions paper
is written by Antoine Joux in DCSSI Crypto Lab(France), This paper helped us to study the existence of
multi-collisions in iterated hash functions 5. It helps us to know that finding the multi-collisions
are tougher to find than the ordinary collisions, it also tell us about the
complexities of the attacks on the system 5. It also mentions that the system has to satisfy
various security properties and in case of an attack to the system ,the system
will be immune to the attack and not let data get stolen from the system,It suggests that the building of a multi-collision system
will be very difficult with an input of variable size 5. The system has to use a compression function whose input sizes are fixed
which is SHA-1 5. A combination of cryptography using AES and
steganography are used for security 6. To increase the security level, the key are
hashed using SHA-1.In this method an advanced concept of combining
cryptography and steganography in image and audio 6. SHA-1 algorithm is used
for encryption and compression for data using 512 bit block size sequentially
7. The new attack on SHA Algorithm has reduced probability and complexity 3.
It has also been presented a chosen-message pre-image attack on MD4 with
complexity below 28 3. By literature survey the question of how SHA is
performed is clear but it has not been proposed for video.

 

                                                                                                                                         
III.       
Secure Hashing Algorithm

Message Digest or Fingerprint is the best method to provide
security as it is the condensed representation
of the data so its size is less as compared
to the original data and it is easy to generate for a given file. It is computationally infeasible to produce two messages
with same message digest. It is also impossible
to recreate a message given a message digest. It provides data integrity
and comparison checking as well as
message integrity validation. It
uses one-way hash functions for generating the hash value of the data. In Public Key Algorithms it is used for password logins, encryption key management, digital signatures, integrity checking, virus and malware scanning, authentication, secure web connections i.e. PGP, SSL.

                                                                                                                                                             
IV.       
Methodology

A.    Video to image conversion

Using the algorithm directly on the
video files will be a very complex computation so to achieve this task very
easily and simply the video files should be first converted into frames and then
after converting it into frames after an interval of just suppose 0.2 sec the
image will be formed by using a for loop and ‘imwrite’ command
from o to 255 i.e. in both direction (rows and columns) as the video is a 2D
representation of 3D object and image is also 2D representation.

 

B.    Colour image to gray

Colour image contains a large number of
pixel value as compared to grayscale image so it would be easier to operate or
perform hash functions on grayscale image so convert the image into gray image
by using a for loop as used above. The coloured
image is the converted into greyscale image this is because the luminance of a
pixel value of a grayscale image ranges from 0 to 255 8.The conversion of a
colour image into grayscale image is converting the rgb values(24bit) into
grayscale value (8bit) for simplycity 8. By converting the colour image or
Rgb into gray we enter into a domain which is much easy for processing and
computation complexity reduces as there are less information present.

 

C.    Append Padding
Bits

First calculate the length of the
message but here the message is a video file which is converted into image
frames or to be precise grayscale image’s which is of 8 bit so first convert it
into 8 parts from MSB to LSB 2. After that message is padded with a 1 and
as many 0’s as necessary to bring the message length to 64 bits fewer than an
even multiple of 512 2. To make
the length congruent to 448 modulo 512.

 

D.   
Append Length

The data is then a fixed length of 448
bits which is 64 less than 512. Then 64 bits are appended to the end of the
padded message. These bits hold the binary format of 64 bits indicating the
length of the original message 2. The output of the first two steps is a message that is an integer
multiple of 512 bits in length in this case image of 512 bits block 2.

 

E.   
Prepare Processing Functions

SHA requires 80 processing functions that are defined below which are used
for various processing to be computed on the raw image for the protection or
security of the data by the eves-dropper or from any unauthorized access by
using these various defined processing Secure hashing Functions 2:

 

F (t;B,C,D) = (B AND C) OR ((NOT B) AND D)      

( 0
<= t <= 19)                                                                (1) F (t;B,C,D) = B XOR C XOR D                   (20 <= t <= 39)                                                                 (2) F (t;B,C,D) = (B AND C) OR (B AND D) OR (C AND D)       (40 <= t <=59)                                                                      (3) F (t;B,C,D) = B XOR C XOR D                        (60 <= t <= 79)                                                                  (4)    F.    Prepare Processing Constants SHA requires 80 processing constant words defined as 2:   K(t) = 0x5A827999                      ( 0 <= t <= 19)   K(t) = 0x6ED9EBA1                     (20 <= t <= 39)   K(t) = 0x8F1BBCDC                    (40 <= t <= 59)   K(t) = 0xCA62C1D6                    (60 <= t <= 79)   G.    Initialize Buffers SHA requires 160 bits or 5 buffers of words (32 bits) for holding the intermediate data and the final hash value the following are the registers which are initialized to 32 bits (hexadecimal values) 2. In 1024 bit SHA algorithm the bit requirement doubles and so does the buffers capacity for storing data. Some of the buffers are given below 2: H0 = 0x67452301 H1 = 0xEFCDAB89 H2 = 0x98BADCFE H3 = 0x10325476 H4 = 0xC3D2E1F0   H.    Processing Message in 512-bit blocks This is the main task of SHA algorithm which loops through the padded and appended message in 512-bit blocks 2. After all the above steps the images are ready in 512 bit block size for processing in the round function and generation of the hash value. Input and predefined functions: ·         M1, 2, ..., L are Blocks of the padded and appended message                 ·         F (0;B,C,D), F (1,B,C,D), ..., F (79,B,C,D) are 80 processing functions       ·         K(0), K(1), ..., K(79) are 80 Processing Constant Words ·         H0, H1, H2, H3, H4, H5 are word buffers with initial values   The picture shown below shows process of Message digest generation using SHA-512 1.   Fig 1: Messsage digest generation    I.      Steps for Round Function           Various logical operators like and, or, xor and various bit wise operators are used like rotation operator for the processing in the round function 2. As the image is divided into blocks of 512 bit size so when the first hash value is generated it is xored with the next data in these round function for further processing and thus so on the lastly the last output which is generated is the final hash value which is stored in the intial buffer 2. The below given are some steps to be followed in the round function 2: For loop on k = 1 to L §  (W(0),W(1),...,W(15)) = Mk then divide Mk into 16 words.           For t = 16 to 79   §  W(t) = (W(t-3) XOR W(t-8) XOR W(t-14) XOR W(t-16)) <<< 1   §  A = H0, B = H1, C = H2, D = H3, E = H4                For t = 0 to 79   §  TEMP = A<<<5 + F (t;B,C,D) + E + W(t) + K(t) E = D, D = C,   §  C = B<<<30,B = A,A = TEMP   §  End of for loop   §  H0 = H0 + A, H1 = H1 + B, H2 = H2 + C, H3 = H3 + D, H4 = H4 + E   §  End of for loop                                                                                                                                                                        V.         Discussion By performing this algorithm on the video file we are expecting the following result that is the video file will be compressed and it will ask for a hash key or finger print for opening the data file. The below given flow chart shows a simplistic step by step procedure for the Secure Hashing Algorithm for video. As discussed above first we have to convert the video into frames of image for simplistic operation and that to into the gray domain which has only 0 to 255 pixel values for simplicity of operation. The conversion of a colour image into grayscale image is converting the RGB values (24bit) into grayscale value (8bit) for simplicity 8. But the image still is a 8 bit image so we have to convert the image into 1 bit 8 image using bit plane slicing and then start the further processing on that one bit image by padding first one's and then zero's until a block size of 448 bits is been formed and in remaining 64 bits the length of each image is padded  separately. The hash value generated after processing of these 1bit individual images will be XOR with the pre-processing functions and pre-processing constant in-order to get a final Hash value which will be transferred as mentioned above to the destination address.       Fig 2: Flow chart for SHA for Video         The video is first converted into 25 frames per second by using  codes in the matlab. The size of the coloured image is shown in fig 2 and 3 which is an unsigned integer 8 image.   Fig 3: Colour image frames     Fig 4: colour image frame specification               The coloured image is the converted into greyscale image this is because the luminance of a pixel value of a grayscale image ranges from 0 to 255. The conversion of a colour image into grayscale image is converting the RGB values(24bit) into grayscale value (8bit) for simplycity 8, which is shown in fig 4 below.     Fig 5: Grayscale image   The matlab code output of the first two steps is obtained which is shown in fig 5 below     Fig 6: Matlab output window for first 2 steps          The matlab output obtained after padding first 1 and then with however amount of zero's required inoder to make the message length 64bits less than 512 bits which is 448 bits so that in last 64 bits length of message can be appended , it is as shown below in fig 6 .                                                                                                                                                                      VI.   Conclusion Thus we conclude for having a SHA securing algorithm for video by generating a message digest of a video by first converting it to images and then applying algorithm on each image separately and combining them to get a compressed output along with a hash value which is unique and is impossible for a intruder to get the original message even if he has a unauthorized access to the message digest or the compressed message.   Acknowledgment We are foremost thankful to the Principal of our college Dr. B. K. Mishra who has taken strenuous efforts in providing us with excellent lab facilities. We are greatly indebted to our internal project guide Prof. Rashmitakumari Mohapatra for her able guidance and enlightened comments, which has helped us in better understanding our project work. We would like to thank Mrs. Dr. Sangeeta Mishra for her helpful suggestions and numerous discussions with which she has guided us. We are also thankful to our Head of Department Prof. Vineet Dongre and Project Co-coordinator Prof. Manoj Chavan who has given us constant motivation, guidance and encouragement for the project. We are also grateful to our classmates and friends who have given us feedback and encouragement. Finally we would wish to thank our college Thakur College of Engineering and Technology for providing us with a platform and the necessary facilities to make this project.   References   1     Behrouz A Forouzan, Debdeep Mukhopadhyay, "Cryptography And Network Security", 2nd ed. McGraw Hill Education, India, 2013, ch. 12, sec. 3, pp. 327–354. 2     2William Stallings, "Cryptography And Network Security", 3rd ed. Pearson Education, India: PLC, 2004, ch. 11, sec. 2, pp. 328–334. 3     3Xiaoyun Wang et al., "Cryptanalysis of the Hash Functions MD4 and RIPEMD", Advances in Cryptology-Eurocrypt, 2005. 4     M. Johnson, Kannan Ramchandran, "Dither-based secure image hashing using distributed coding"International Conference on Image Processing,2003. 5     Antonie Joux,"Multicollision in iterated hash function A to cascaded constructions", DCSSI Crypto Lab, France, 2004. 6     Ashams Mathew, "Advanced Cryptographic Steganography Using     Multimedia Files", Researchgate, India, 2012. 7   D. Eastlake, P. Jones, "US Secure Hash Algorithm",Cisco Systems, 2001 8   C. Saravanan, "Color Image to Grayscale Image Conversion", IEEE Xplore Digital Library, 12 April 2010.