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Pseudorandomness facts for kids

Kids Encyclopedia Facts

Pseudorandomness is a way of creating something that looks random, but actually isn't. Imagine flipping a coin, but you know exactly how it will land every time. That's a bit like pseudorandomness! Even though the results seem unpredictable, they are made by a process that can be figured out.

This "almost random" process is super important for things like online security. Since the results can be predicted, it's really important to keep the starting point (called a "seed") and the process itself a secret. If someone knows the seed and the process, they could guess the "random" numbers.

Why We Need Random Numbers

Creating random numbers has many uses, especially in statistics and computer simulations. Before computers, people who needed random numbers would use things like dice, cards, or roulette wheels. They even used special random number tables that were already made.

Early Attempts to Make Random Numbers

One of the first big efforts to create many random numbers was in 1927. Cambridge University Press published a list of 41,600 numbers made by a person named L.H.C. Tippett. Later, in 1947, the RAND Corporation used a computer to simulate a roulette wheel to make random numbers. They published their results in 1955 in a book called "A Million Random Digits with 100,000 Normal Deviates".

How "Almost Random" Numbers Are Made

Truly random numbers are hard to get. You could use things like radioactive decay (from radioactive stuff) or even the static noise between radio stations. These methods can create numbers that are truly random, but they are very slow.

Because they are so slow, people found a clever trick. Instead of using these slow methods to make all the numbers, they used them to create just one starting number, or "seed." Then, a computer program uses this seed to quickly make many more numbers that look random. The fewer numbers created by the slow, truly random process, the more "random" the final result seems. Another way to get a good seed is to combine the exact timings of many people pressing keys on a keyboard.

Sometimes, even these "almost random" numbers can be predicted. However, it becomes much harder to predict them when you only have a small amount of the numbers.

Pseudorandomness in Computer Science

In theoretical computer science, a group of numbers is called pseudorandom if it looks very similar to a truly random group of numbers. This idea is very important in cryptography, which is the science of secure communication. It helps make sure that secret codes and online messages stay safe.

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Pseudorandomness Facts for Kids. Kiddle Encyclopedia.