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」

In this paper, we consider user authentication (UA) for wireless sensor networks. UA is a fundamental issue in designing dependable and secure systems. Imagine that a wireless sensor network is deployed in an intelligent building, a hospital, or even a university campus, to allow legitimate users to send queries and retrieve the respective result at any of the sensor nodes. Importantly, the system needs to provide a means of user authentication to verify if the user is valid. We propose a dynamic strong-password based solution to this access control problem and adapt it into a wireless sensor network environment. The proposed strong-password authentication approach imposes very light computational load and requires simple operations, such as one-way hash function and exclusive-OR operations. We present the design of the proposed scheme and discuss how to make use of the security features on MAC sublayer (medium access control) based on the IEEE 802.15.4 specification. Analysis on security and communication costs is presented to evaluate the effectiveness of the proposed scheme.

A dynamic user authentication scheme for wireless sensor networks

Over the last few years, many researchers have paid a lot of attention to the user authentication problem. However, to date, there has been relatively little research suited for wireless sensor networks. Recently, Wong et al. proposed a dynamic user authentication scheme for WSNs that allows legitimate users to query sensor data at every sensor node of the network. We show that Wong et al.'s scheme is vulnerable to the replay and forgery attacks and propose a lightweight dynamic user authentication scheme for WSNs. The proposed scheme not only retains all the advantages in Wong et al.'s scheme but also enhances its security by withstanding the security weaknesses and allows legitimate users to change their passwords freely. In comparison with the previous scheme, our proposed scheme possesses many advantages, including resistance of the replay and forgery attacks, reduction of user's password leakage risk, capability of changeable password, and better efficiency.

An Improved Dynamic User Authentication Scheme for Wireless Sensor Networks

Two-factor mutual authentication based on smart cards and passwords

Seamless handover over multiple access points is highly desirable to mobile nodes, but ensuring security and efficiency of this process is challenging. This paper shows that prior handover authentication schemes incur high communication and computation costs, and are subject to a few security attacks. Further, a novel handover authentication protocol named PairHand is proposed. PairHand uses pairing-based cryptography to secure handover process and to achieve high efficiency. Also, an efficient batch signature verification scheme is incorporated into PairHand. Experiments using our implementation on laptop PCs show that PairHand is feasible in real applications.

Secure and Efficient Handover Authentication Based on Bilinear Pairing Functions

Enhanced authentication scheme with anonymity for roaming service in global mobility networks

User identification is an important access control mechanism for client-server networking architectures. The concept of single sign-on can allow legal users to use the unitary token to access different service providers in distributed computer networks. Recently, some user identification schemes have been proposed for distributed computer networks. Unfortunately, most existing schemes cannot preserve user anonymity when possible attacks occur. Also, the additional time-synchronized mechanisms they use may cause extensive overhead costs. To overcome these drawbacks, we propose a secure single sign-on mechanism that is efficient, secure, and suitable for mobile devices in distributed computer networks.

A Secure Single Sign-On Mechanism for Distributed Computer Networks

In 2000, Saeednia proposed a new scheme to make the Hill cipher secure. The author makes use of permutations of columns and rows of a matrix to get a different key for encrypting each message. This paper shows that the cipher key Ht can be obtained by parameter u. Besides, the Saeednia's scheme costs a lot of time in matrix computation. To overcome the drawbacks of Saeednia's scheme, a more secure cryptosystem with a one‐way hash function is proposed.

https://ir.nctu.edu.tw:443/bitstream/11536/26412/1/000223895700013.pdf

Comments on Saeednia's Improved Scheme for the Hill Cipher

In 2000, Saeednia proposed a new scheme to make the Hill cipher secure. The author makes use of permutations of columns and rows of a matrix to get a different key for encrypting each message. This paper shows that the cipher key Ht can be obtained by parameter u. Besides, the Saeednia’s scheme costs a lot of time in matrix computation. To overcome the drawbacks of Saeednia’s scheme, a more secure cryptosystem with a one-way hash function is proposed.

COMMENTS ON SAEEDNIA's IMPROVED SCHEME FOR THE

Most of existing user authentication schemes require high computation cost of exponentiation operations for the purpose of security. However, it is not suitable for mobile devices. In this article, we propose a low computation cost user authentication scheme for mobile communication. Our scheme uses only one-way hash functions and smart cards and can be implemented efficiently. The proposed scheme not only resolves the weakness appeared in existing methods but also suits for mobile communication.

Chia-Yin Lee

Papers

Enhanced authentication scheme with anonymity for roaming service in global mobility networks

A Secure Single Sign-On Mechanism for Distributed Computer Networks

Comments on Saeednia's Improved Scheme for the Hill Cipher

COMMENTS ON SAEEDNIA's IMPROVED SCHEME FOR THE

An improved low computation cost user authentication scheme for mobile communication