Are computer random numbers actually random?

Most are not. They are 'Pseudo-Random' (PRNG). They use a mathematical formula starting from a 'seed' number (often the current time in milliseconds). If you knew the seed and the formula, you could predict the next number perfectly.

What is True Randomness (TRNG)?

True randomness comes from physical phenomena, like atmospheric noise, radioactive decay, or thermal noise in hardware. These cannot be predicted by math.

Is it safe for passwords?

For most people, yes. Cryptographically secure PRNGs (CSPRNG) are designed so that even if a hacker has a supercomputer, they cannot predict the next number. Standard PRNGs (like Math.random() in older browsers) should NOT be used for security.

The Ghost in the Machine: How RNG Works

Computers are logical machines. Asking them to be "random" is like asking a robot to tell a joke. It has to fake it.

Pick a Number

Generate a random number between any range.

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The "Seed" Problem

Imagine a book of 1 million numbers. If I tell you "Start at page 50, line 3", you will always find the same number. That starting instruction is the "Seed". Computers usually use the current time (e.g., 12:05:03.453) as the seed. If two computers run the same code at the EXACT same millisecond, they will produce the EXACT same "random" number sequence.

Why It Matters for Gaming

In video games, "RNG" determines loot drops or critical hits. Speedrunners sometimes manipulate RNG (called "RNG Manipulation") by performing specific actions at specific frames to force the game to generate the "random" item they want.

Why It Matters for Crypto

If a hacker can guess the seed used to generate your private key, they own your wallet. This is why secure systems use "Entropy" (mouse movements, keyboard timing, fan speed) to create truly unpredictable seeds.

The Ghost in the Machine: How RNG Works

Pick a Number

The "Seed" Problem

Why It Matters for Gaming

Why It Matters for Crypto

RNG FAQs