h1 { margin-top: 0.28cm; margin-bottom: 0.14cm; direction: ltr; font-variant: small-caps; color: rgb(0, 0, 0); text-align: center; page-break-inside: avoid; }h1.western { font-family: “Times New Roman”,serif; font-size: 10pt; font-weight: normal; }h1.cjk { font-family: “MS Mincho”,”?? ??”,monospace; font-size: 10pt; font-weight: normal; }h1.ctl { font-family: “Times New Roman”,serif; font-size: 10pt; font-weight: normal; }p { text-indent: 0.51cm; margin-bottom: 0.
21cm; direction: ltr; color: rgb(0, 0, 0); line-height: 95%; text-align: justify; }p.western { font-family: “Times New Roman”,serif; font-size: 10pt; }p.cjk { font-family: “MS Mincho”,”?? ??”,monospace; font-size: 10pt; }p.ctl { font-family: “Times New Roman”,serif; font-size: 10pt; }a:link { } Gautam Kumar Jha Computer Engineering Thakur College of Engineering & Technology Mumbai, India gautamjha229@gmail.
com Dr. R. R. Sedamkar Computer Engineering Thakur College of Engineering & Technology Mumbai, India [email protected] Abstract—Inthe recent trend, data are increasing enormously in day to day life.Securing data is one of the main challenge nowadays, as data travelsthrough different medium where medium is not secured.
Toprevent confidential data from an unauthorized access there arenumber of approaches. The methods of symmetric key cryptography andasymmetric key cryptography can be used for encrypting and decryptingthe multimedia files.Thispaper mainly focuses on a proposed technique used for encrypting anddecrypting multimedia data through the hybrid proposed model based onthe assemblage of Advanced Encryption Standard and Deffie Hellman KeyExchange Algorithm. The proposed methodgenerates a key by sender using Deffie Hellman algorithm and passedto the AES algorithm which act as a key for encrypting multimediadata. The encrypted data will be decrypted by the receiver key usingDeffie Hellman and AES.
Theadvantage of this proposed hybrid model is that it will provide thesecurity to the multimedia data and also fill the gap of storage,speed and security. It is even used for societal for communication ofdata over network.Keywords—Security,Multimedia, Cryptography, DES(Data Encryption Standard),AES(Advanced Encryption Standard).I.
Introduction Ina communication system, security of information is a major concernnowadays. There are lots of techniques like hashing, stegnography,cryptography that make available use for the safety of essentialinformation. Confidential data can be protected with the applicationof Encryption and Decryption techniques as it takes an importantpart. In the ancient times, through the study of past events the datawere made unreadable by scrambling the contents of information tokeep it secret. Cryptography algorithms like DES, AES, Blowfish, RSAand Deffie Hellman provides higher level of security by using a pairof key for both encryption and decryption.
AESis a symmetric key algorithm where the plain text size is a blocksize of 128,192,256 bit and the length of key is same as the size ofthe plain text i.e. 128,192,256 bits. It involves basically foursteps as follows: Byte Substitution Shifting of rows Mix columns Add a round key Ithas total rounds of 10, 12 or 14 to encrypt data depending on theplain text size of 128, 192 and 256 respectively. Initially bits areconverted into bytes.
After which, data are substituted from thesubstitution box and are arranged in a matrix form. In the furtherstep shifting of rows take place depending on the offset used i.e.offset 0, offset 1, offset 2 and offset 3.
Offset 0 means data willremain on the same position where offset 1 means data will be shiftedby one position and respectively. In the next step columns are mixedin a similar approach as of rows shifting. At the last, Addround keyis added after the mixing of columns and the process repeats till thelast rounds depending on the plain text size.DeffieHellman is a key exchange algorithm, in which is keys are used forcommunication to exchange data in a public network. It involvesbasically five steps as follows: Global Public elements User ‘A’ Key generation User ‘B’ Key generation Generation of secret key by user ‘A’ Generation of secret key by user ‘B’ Initiallythe two global public elements are used one is a prime number elementand other is a primitive root of that prime number. In the next step,user A selects a random number which is smaller than the prime numberand it is used as a private key.
In the next step user B selects arandom number which is smaller than the prime number and it is usedas a private key. In the fourth step user B share his private keywith user A and then user A generates a secret key for exchangingdata. Similarly, user B generates a secret key for exchanging data.
In the last two steps we get the same result which is used as ashared secret key. Theresult provided by Advanced Encryption Standard is much better andfaster than any other algorithm like Data Encryption Standard. DeffieHellman Key Exchange algorithm exchanges there private key and publickey to prepare a common shared key for exchanging the data.
Theproposed hybrid algorithm is designed by combining AES and DHM toencrypt the multimedia data by converting it into a bit equivalent toreduce the overall time constraint and provide high level ofsecurity.
