Is Shuffle Really Random? Understanding PRNG in Shuffle Algorithms

Explore how shuffle algorithms use pseudorandom number generators to approximate randomness and why true randomness is hard to achieve.

Published

Video transcript

Shuffle algorithms used by most devices and software aim to be random, but true randomness is difficult to achieve. Instead, they use pseudorandom number generators (PRNGs), which provide a sequence of numbers that approximates the properties of random numbers. While not perfectly random, PRNG-generated shuffles are generally random enough for most practical purposes.

Questions and answers

  1. What is a pseudorandom number generator (PRNG)?

    A pseudorandom number generator (PRNG) is a computational algorithm that generates sequences of numbers approximating the properties of random numbers, but these sequences are deterministic and not truly random.

  2. Why isn’t shuffle truly random on devices?

    Most shuffles rely on PRNGs, which are deterministic and thus can’t produce true randomness, but they are random enough for practical uses like music playlists or card games.

  3. How do shuffle algorithms work in software?

    Shuffle algorithms generate a pseudorandom sequence using PRNGs and then reorder the items accordingly to mimic randomness in the final output.