Random numbers generator

A number is drawn from a set of numbers with no recognizable pattern. These numbers are usually independent of each other but at times they follow some certain distribution. For example, the heights of all the students in a school follow the normal distribution around the median height. Thus, the number drawn in selecting a random student’s height would more likely be near the median height rather than one that is very tall or very short. All of the random number generators described above are based upon the assumption that the numbers produced are truly random and uniformly distributed over the range of the values taken by the random variable.

A random number generator is a device that generates one or more random numbers, all being within a defined range. These generators may be hardware generators or pseudo-random number generators. Examples of hardware-based random number generators may include objects such as dice or coins, which would have to be physically flipped.

On the other hand, a pseudo-random number generator is an algorithm that generates a sequence of numbers supposedly randomly drawn but not truly random. Most computer-based random number generators are pseudo-random number generators. However, the numbers the computer generates are somewhat random. The above-mentioned generators also belong to the same group, termed pseudo-random number generators. While the random numbers that they produce are good enough for most uses, they are unacceptable for any cryptographic uses. On the other hand, the real random numbers are generated from physical phenomena—such as atmospheric noise, thermal noise, and other quantum effects. This notion of bias extends to the schemes that are used in the generation of true random numbers.