A Method to Generate Random Number for Cryptographic Application

Random number is widely used in cryptographic applications, which is mainly used as key. Because the security of key totally depends on the amount and randomness of itself, it´s very important to produce random numbers for cryptographic applications. This paper presents a method to generate random numbers for cryptographic applications. NIST Statistical Test Suite which provides 15 statistical methods is used to test the randomness of the random number generated by this method. Because the tests focus on a variety of different types of non-randomness, not all tests are needed. The chosen statistical tests are Frequency (Monobit) Test, Frequency Test within a Block, The Cumulative Sums (Cusums) Test, The Runs Test, Test for the Longest Run of Ones in a Block, Discrete Fourier Transform (Specral) Test, Approximate Entropy Test and Serial Test. The result of tests shows that the random number generated by the random number generator is random. Therefore the conclusion is the random number generated is random enough for cryptographic applications.