Keybundle assessment tools

In order to be able to assess the quality of the generated key bundles, some analysis functions have been added to the Encrypter-X. They allow an examination of key structures in terms of uniformity of distribution (uniform occurrence of byte values), goodness of randomness, and dissimilarity between different key bundles.

Uniformity: The frequencies of occurrence of the individual bytes between 1 and 255 are determined and then normalized to the maximum frequency. Then the mean value of all frequencies gives a good value for the evaluation of the uniformity. This is the better the closer the value is to "1". To exclude the possibility that there are nevertheless some bytes that occur much less frequently than others, the difference between the maximum and minimum relative frequencies is formed and this value should be as close as possible to "0".

Goodness of randomness: To be able to assess the randomness, an instrument known from acoustics is applied. White noise is randomly strung together amplitude values and results in an equally random frequency spectrum that can be calculated with a Fast Fourier Transform (FFT). The FFT analysis function of the Encrypter-X visualizes key bundle skips (1024 bytes) and the resulting spectrum from which the quality of the randomness can be recognized.

Pattern comparisons: How well key bundles differ from each other can be seen by examining how often the individual byte sequences (patterns) of one key bundle occur in the other. These frequencies are determined starting with 3 byte patterns for all possible byte sequences and then ascending for 4 byte patterns etc. until none of the patterns occur in the other key bundle. For the true random key bundles generated by Encrypter-X, ≈ 0.5% for 3-byte patterns and ≈ 0.001% for 4-byte patterns and 5-byte patterns or larger occur almost not at all, even for very large key bundles.