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With the spread of digital data around the world through the internet, the security of the data has raised a
concern to the people. Many methods are coming up to protect the data from going into the hands of the
unauthorized person. Steganography and cryptography are two different techniques for data security. The
main purpose in cryptography is to make message concept unintelligible, while steganography aims to hide
secret message. Digital images are excellent carriers of hidden information. We propose a method of
combining steganography and cryptography for secret data communication. In this paper, we propose a
high-performance JPEG steganography along with a substitution encryption methodology. The approach
uses the discrete cosine transform (DCT) technique which used in the frequency domain for hiding
encrypted data within image. Experimental results show that the visual and the statistical values of the
image with encrypted data before the insertion are similar to the values after the insertion thus reduces the
chance of the confidential message being detected and enables secret communication. The effectiveness of
the proposed method has been estimated by computing Mean square error (MSE) and Peak Signal to Noise
Ratio (PSNR).

With the spread of digital data around the world through the internet, the security of the data has raised a
concern to the people. Many methods are coming up to protect the data from going into the hands of the
unauthorized person. Steganography and cryptography are two different techniques for data security. The
main purpose in cryptography is to make message concept unintelligible, while steganography aims to hide
secret message. Digital images are excellent carriers of hidden information. We propose a method of
combining steganography and cryptography for secret data communication. In this paper, we propose a
high-performance JPEG steganography along with a substitution encryption methodology. The approach
uses the discrete cosine transform (DCT) technique which used in the frequency domain for hiding
encrypted data within image. Experimental results show that the visual and the statistical values of the
image with encrypted data before the insertion are similar to the values after the insertion thus reduces the
chance of the confidential message being detected and enables secret communication. The effectiveness of
the proposed method has been estimated by computing Mean square error (MSE) and Peak Signal to Noise
Ratio (PSNR).

Secured Communication involves Encryption process at the sending end and Decryption process at the
receiving end of the communication system. Many Ciphers have been developed to provide data security .
The efficiency of the Ciphers that are being used depends mainly on their throughput and memory
requirement. Using of large key spaces with huge number of rounds with multiple complex operations may
provide security but at the same time affects speed of operation. Hence in this paper we have proposed a
method to improve Caesar cipher with random number generation technique for key generation operations.
The Caesar cipher has been expanded so as to include alphabets, numbers and symbols. The original
Caesar cipher was restricted only for alphabets. The key used for Caesar Substitution has been derived
using a key Matrix Trace value restricted to Modulo 94. The Matrix elements are generated using recursive
random number generation equation, the output of which solely depends on the value of seed selected . In
this paper, we made an effort to incorporate modern cipher properties to classical cipher. The second stage
of encryption has been performed using columnar transposition with arbitrary random order column
selection. Thus the proposed Scheme is a hybrid version of classical and modern cipher properties. The
proposed method provides appreciable Security with high throughput and occupies minimum memory
space. The Method is resistant against brute-force attack with 93! Combinations of keys, for Caesar
encryption

The encryption standards such as DES (Data Encryption Standard), AES (Advanced Encryption Standard) and EES (Escrowed Encryption Standard) are widely used to solve the problem of communication over an insecure channel. With advanced technologies in computer hardware and software, these standards seem not to be as secure and fast as one would like. In this paper we propose a fast and secure encryption algorithm using substitution mapping, translation and transposing operations. The proposed symmetric encryption technique has two advantages over traditional schemes. First, the encryption and decryption procedures are much simpler, and consequently, much faster. Second, the security level is higher due to the inherent poly-alphabetic nature of the substitution mapping method used here, together with the translation and transposition operations performed in the algorithm. In this paper, the encryption and decryption procedures are explained and the performance is compared with popular e...

In this paper a detailed analysis of Data Encryption Standard (DES), Triple DES (3DES) and Advanced Encryption Standard (AES) symmetric encryption algorithms in MANET was done using the Network Simulator 2 (NS-2) in terms of energy consumption, data transfer time, End-to-End delay time and throughput with varying data sizes. Two simulation models were adopted: the first simulates the network performance assuming the availability of the common key, and the second simulates the network performance including the use of the Diffie-Hellman Key Exchange (DHKE) protocol in the key management phase. The obtained simulation results showed the superiority of AES over DES by 65%, 70% and 83% in term of the energy consumption, data transfer time, and network throughput respectively. On the other hand, the results showed that AES is better than 3DES by approximately 90% for all of the performance metrics. Based on these results the AES was the recommended encryption scheme.

Information security is an important issue. Hill Cipher is one of the most famous symmetric cryptosystem that can be used to protect information from unauthorized access.Hill cipher is a polygraph substitution cipher based on linear algebra. Invented by Lester S. Hill in 1929, it was the first polygraph cipher which was practical to operate on more than three symbols at once, Hill Cipher has many advantages in data encryption. First, it is resistant to the frequency letter analysis. It's also very simple since it uses matrix multiplication. Finally, it has high speed and high throughput [1,13,14], However, noninvertible key matrix over is the main disadvantage of Hill Cipher, because few of the matrices have inverses over. This means that the encrypted text can't be decrypted [2]. This paper suggests a new technique in Hill Cipher algorithm to overcome its major problem-noninvertible key matrix. also our paper suggest enhancement the security of Hill Cipher against known p...

The security concerns would be still there in cloud systems. Cryptography consists of the encryption-decryption techniques. There are many schemes, algorithms those can be used for security purposes. DNA is now mostly a theoretical concept but if implemented in future would be providing most strong and secure system. In this paper it has been proposed that DNA cryptographic algorithms are adopted for the optimization of data security in cloud security. So that cloud system would be most

In this work we show the weakness of Asymmetric Cryptosystem based on Phase-Truncated Fourier Transforms (PTFTs). The weakness that we are trying to show is the possibility of retrieving the “plaintext” image without using its corresponding “ciphertext”, the proposed procedure is based on the use of any image (binary image, random image ...) to recover the primary image after decryption. A series of computer simulations have shown the weakness of Asymmetric Cryptosystem based on Phase-Truncated Fourier Transforms.