Scatter plot of the p-value results for 188 tests performed on binary sequences that were generated by various methods, the red line denotes the threshold for which the p-value indicates that the sequence has not passed a given test. (a) The sequence generated using LED light passing through a polarizing beamsplitter. (b) Same sequence after applying the von Neumann’s algorithm for bias removal. (c) Pseudo-random numbers generated with the rand( ) method in the C programming language. (d) Random numbers taken from the true random number generator implemented by Hotbits [11]. We can see how von Neumann’s algorithm greatly improves the performance of our random number generator.