| Summary: | 碩士 === 國防大學 === 資訊管理學系 === 102 === With information technology rapidly developing, lots of applications are available over the Internet. Recently, the Chinese mainland hackers keep improving their information security attack skills to eavesdrop confidential documents from opponents.For assuring confidentiality of classified documentations, data encryption is the best solution. Nowadays, two categories of encryption mechanisms, symmetric and asymmetric, are proposed;and,symmetric block encryption mechanisms are widely adopted to encrypt huge volume of documentations.
This study bases on a pseudo random number generator (PRNG) to propose a symmetric block encryption scheme. Usually, security strength of a PRNG-based encryption scheme depends on the randomness of its random number sequence.The linear congruential generator (LCG) is most widely applied in many applications since it is simple and process quickly. However, there exists a fatal drawback in the LCG;attackers can derive a random number seed from collected a serial of random numbers. This would let an attacker can compromise a ciphered confidential document easily.Therefore, this study proposes an enhanced LCG to strengthen the proposed PRNG-based encryption scheme.In this study, we use the chi-square test mode in statistics to randomness of random numbers generated by our proposed enhanced LCG. Moreover, we base on our proposed enhanced LCG to design a symmetric block encryption scheme with different sizes of substitution boxes/ inverse substitution boxes. A prototype of the proposed symmetric block encryption scheme is implemented with C. With the implemented prototype, we understand the feasibility and performance of our proposed symmetric block encryption scheme.
|
|---|
