The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

PCA filtering and probabilistic SOM for network intrusion detection

Network security is an important aspect of information sharing. Attempts have been made to remove various insecurities over internet. For this, many technological implementations and security policies have been developed. The amount of data, transferred, is not a factor. The basic factor is, how much security, the channel provides while transmitting data. Cryptography is one such technique, which allows secure data transmission without losing its confidentiality and integrity. Based on the key distribution, cryptography is further classified into two major types-Symmetric Key Cryptography and Asymmetric Key Cryptography. In this paper, we have surveyed the traditional algorithms, along with the proposed algorithms based on their pros and cons, related to Symmetric and Asymmetric Key Cryptography. We have also compared the importance of both these cryptographic techniques. The proposed algorithms proved to be highly efficient in their respective grounds but there are certain areas that remained open, related to these algorithms, and have not yet been thoroughly discussed. This paper also presents an appropriate future scope related to these open fields.

A comparative survey of Symmetric and Asymmetric Key Cryptography

The Hill cipher algorithm is one of the symmetric key algorithms that have several advantages in data encryption. But, the inverse of the key matrix used for encrypting the plaintext does not always exist. Then if the key matrix is not invertible, then encrypted text cannot be decrypted. In the Involutory matrix generation method the key matrix used for the encryption is itself invertible. So, at the time of decryption we need not to find the inverse of the key matrix. The objective of this paper is to encrypt an image using a technique different from the conventional Hill Cipher. In this paper a novel advanced Hill (AdvHill) encryption technique has been proposed which uses an involutory key matrix. The scheme is a fast encryption scheme which overcomes problems of encrypting the images with homogeneous background. A comparative study of the proposed encryption scheme and the existing scheme is made. The output encrypted images reveal that the proposed technique is quite reliable and robust.

Image Encryption Using Advanced Hill Cipher Algorithm

The importance of image security in the field of medical imaging is challenging. Several research works have been conducted to secure medical healthcare images. Encryption, not risking loss of data, is the right solution for image confidentiality. Due to data size limitations, redundancy, and capacity, traditional encryption techniques cannot be applied directly to e-health data, especially when patient data are transferred over the open channels. Therefore, patients may lose the privacy of data contents since images are different from the text because of their two particular factors of loss of data and confidentiality. Researchers have identified such security threats and have proposed several image encryption techniques to mitigate the security problem. However, the study has found that the existing proposed techniques still face application-specific several security problems. Therefore, this paper presents an efficient, lightweight encryption algorithm to develop a secure image encryption technique for the healthcare industry. The proposed lightweight encryption technique employs two permutation techniques to secure medical images. The proposed technique is analyzed, evaluated, and then compared to conventionally encrypted ones in security and execution time. Numerous test images have been used to determine the performance of the proposed algorithm. Several experiments show that the proposed algorithm for image cryptosystems provides better efficiency than conventional techniques.

/pdf/lightweight-encryption-technique-to-enhance-medical-image-4x3tigevhd.pdf

Lightweight Encryption Technique to Enhance Medical Image Security on Internet of Medical Things Applications

In this paper, methods of generating self-invertible matrix for Hill Cipher algorithm have been proposed. The inverse of the matrix used for encrypting the plaintext does not always exist. So, if the matrix is not invertible, the encrypted text cannot be decrypted. In the self-invertible matrix generation method, the matrix used for the encryption is itself self-invertible. So, at the time of decryption, we need not to find inverse of the matrix. Moreover, this method eliminates the computational complexity involved in finding inverse of the matrix while decryption.

/pdf/novel-methods-of-generating-self-invertible-matrix-for-hill-31qsq7z700.pdf

Novel Methods of Generating Self-Invertible Matrix for Hill Cipher Algorithm

Hill cipher algorithm is one of the symmetric key algorithms that have several advantages in data encryption. But, the inverse of the key matrix used for encrypting the plaintext does not always exist. Then if the key matrix is not invertible, then encrypted text cannot be decrypted. In the Self-invertible matrix generation method the key matrix used for the encryption is self- invertible. So, at the time of decryption we need not to find the inverse of the key matrix. This paper presents image encryption technique using the Hill cipher. Here we presented a proposed method of generating self-invertible matrix for Hill Cipher algorithm. Moreover this method eliminates the computational complexity involved in finding inverse of the matrix while decryption. However, a main drawback of this algorithm is that it encrypts identical plaintext blocks to identical ciphertext blocks and cannot encrypt images that contain large areas of a single color. Thus, it does not hide all features of the image which reveals patterns in the plaintext. But it works well for all other types of gray scale images as well as colour images.

/pdf/image-encryption-using-self-invertible-key-matrix-of-hill-1dtlcm1xk2.pdf

Image Encryption Using Self-Invertible Key Matrix of Hill Cipher Algorithm

In this paper a novel offline signature verification scheme has been proposed. The scheme is based on selecting 60 feature points from the geometric centre of the signature and compares them with the already trained feature points. The classification of the feature points utilizes statistical parameters like mean and variance. The suggested scheme discriminates between two types of originals and forged signatures. The method takes care of skill, simple and random forgeries. The objective of the work is to reduce the two vital parameters False Acceptance Rate (FAR) and False Rejection Rate (FRR) normally used in any signature verification scheme. In the end comparative analysis has been made with standard existing schemes.

/pdf/improved-offline-signature-verification-scheme-using-feature-2ea44vez75.pdf

Improved offline signature verification scheme using feature point extraction method

In this paper, a secure and efficient protocol for vehicular ad hoc networks has been proposed that ensures both message authentication and privacy preservation. As safety related message may contain life critical information, it is a necessity that the sender as well as the message are authentic. The proposed scheme is based on a secure elliptic curve digital signature algorithm approach. The proposed scheme supports conditional privacy, where the user's location can be revealed at the willingness of the user. Apart from this, the scheme is secure against attacks like DoS, Sybil and Grey/Black Hole attacks. From the comparison with previously proposed schemes, it is found that the proposed scheme as based on elliptic curve discrete logarithmic problem, outperforms existing algorithms based on integer factoring and discrete logarithmic problem.

Saroj Kumar Panigrahy

Papers

Image Encryption Using Advanced Hill Cipher Algorithm

Novel Methods of Generating Self-Invertible Matrix for Hill Cipher Algorithm

Image Encryption Using Self-Invertible Key Matrix of Hill Cipher Algorithm

Improved offline signature verification scheme using feature point extraction method

A secure and efficient message authentication protocol for VANETs with privacy preservation