# Cryptography Projects.

Cryptography projects construct and analyze security protocols and algorithms to make improvement in integrity & data confidentiality. Data confidentiality and authentication in information system is secured using cryptographic concepts.  Among the present unauthorized users a secure communication is provided by cryptography. Cryptography projects gives out encryption algorithms fundamental knowledge. Cryptography projects are combined with network for providing security among the networks.  Cryptography projects are carried out by research scholars and students who are in communication, IT, networking and computer science field. Printed text and pictures are encrypted by a special secure cryptographic technique called visual cryptography. This is very useful in the field of crime management. Image colours, pixel, contrast and a type of member and secrete images and image format are used by visual cryptography. The main focus of visual cryptography projects is to protect authorized data of user from unauthorized system. It is very efficient in sharing secured messages. The original image is split into two and the secret message is introduced in one part of the secrete image. The parts of image are brought together in decrypting messages

## Algorithms used in Cryptography Projects.

Symmetric Encryption Algorithm:

Secret key cryptography is known as symmetric encryption algorithm. Same algorithm is used by receiver and sender while secret key for decryption and encryption. Encryption key could be generated quickly. In a secure way, secret key could be exchanged.

DES(Data Encryption Standard): In symmetric key algorithm, DES is the best algorithm. 64 bit character is used along with mono alphabetic ciphering. 19 distinct stages are contained. S- Box method is provided by NSA for DES. The major challenges faced here is slow encryption.

AES: Belgian cryptographer designed AES. Blocks and keys of variable length are used for encryption. 128, 192 or 256 are the AES key length, while block length varies from 128,192 and 256 bits.

IDEA (International Data Encryption Algorithm): James Mersey and xueji a lai developed IDEA. Today’s cryptography area mostly uses IDEA. 128 bit key is used for algorithm.

Asymmetric Encryption Algorithm:

For encryption and decryption purpose various algorithm and keys are used in asymmetric algorithm.

RSA (Ron Rivets, Adi Shamir And Leonard Ad Leman): Euler’s function does the work of RSA. It is based on factoring problem. The prime number p and q for generating public and private key are selected in this algorithm. Multiplication of 2 prime numbers private key is generated and multiplication of p-1 and q-1 public key is generated. For encryption purpose C=Pt  equation is used while P=Cd for decryption.

Diffie Hellman Key Exchange: It just do exchange of cryptographic keys among sender and receiver. In a secure way private key is shared on a public communication channel. Common numeric values are accepted by sender and receiver and then secured key is created.

DSA(Digital Signature Algorithm): NSA has developed DSA for authentication of message, digital signature is provided. It is at times called as digital signatures standards.

Hashing Functions:

Message direct algorithm is other name of hashing function. For encoding of plain text fixed length of hash value is used. Digital finger print of secure content is used for hash function that could not be altered by unauthorized users. To encrypt the operating system password it is used. Integrity of secure contents could be measured.

Message digest Algorithm5 (MD5): To overcome the problems faced in MD2 and MD4 algorithm MD5 algorithm was designed. Large number of secure messages could be encrypted in MD5. Many encryption applications use MD5.

Symmetric MAC: To detect and modify content by an intruder, symmetric MAC is used. Last block of key with plain text message is send to receiver.

### Schemes of Visual Cryptography Projects.

Dynamic Visual Cryptography: The capacity of scheme is increased through this method. Through this multiple secret sharing is obtained. In a set of secret images more than one secret message can be stored through this method.

Multi Pixel Encoding: Through this scheme more than one pixel can be encoded. Efficiency of encoding is quiet poor in this method. Number of pixels equals the encoding length while secret image conversion.

Color Visual Cryptography: A series of conversation takes place in this method. First a pixel from original image is created as many sub pixels. These sub pixels are then converted into C color region. C color region has one colored pixel area and the rest of pixel region is black color. This is used for more effective secret image sharing.

Visual Cryptography for Gray Level Images: For gray level images dithering techniques is used. Gray level values are converted as binary values in this method. The image quality of gray level image should be improved.

Halftone Visual Cryptography: Original binary images are encrypted as random binary number patterns through this method. OR and EXOR operations are performed to improve the qualities of subset. No visual meaning can be found in binary patterns. Blue noise dithering principles is the base of halftone. In which cluster algorithm is used to encode secret images as halftone images.

#### Applications of  Visual Cryptography Projects:

Human Machine Identification Using Visual Cryptography: User and security system makes use of this application to share a secret message. For this the identity of user should be submitted to the system. As this identity helps in discriminating authorized user from unauthorized user.

Biometrics: Original data is converted into two images through this method. This system needs more security than password system.

Offline QR Code Authentication: The QR code is an unreadable 2D bar code. It has black module in white background arranged in square pattern. It makes use of a special code with special feature.

• High Capacity of Encoding Images.
• Small Print out Size.
• 7089 Numeric Characters.
• Separate Encoding Region And Function Pattern.
• It has 360 Rotations.