STATISTICAL ANALYSIS OF THE UNIFORMITY OF CRYPTOGRAMS IN THE DYNAMIC CRYPTOSYSTEMS

The topic of this thesis was first introduced as a part of a research concerning the application of cryptography in special cases. The tools for the work were developed according to the main scope of the project – pseudo random number generator, encryption using one-time pad algorithm and χ^2 test analysis. The research work required knowledge on cryptology, introduction into its important tasks and requirements. The essential basics are introduced in this thesis. They allow not only to familiarize oneself with cryptology in general but also to understand the difference between various enciphering systems. The main aim was to create the software allowing byte-by-byte encryption of plaintext to be encrypted using simple XOR operation with one-time pad algorithm. For the key, pseudo random number generator was used. Each type of file passed up to 15 rounds of encryption. After each round χ^2 goodness of fit test for distribution of bytes was performed. Results of the analysis of influence and necessity of particular amount of rounds for different types of plaintext are provided as the result of the research. Keywords: One-time pad, chi2, encryption, goodness of fit, pseudo random number generator, statistical analysis