What is the difference between a non-secure random

Question

As the title says: What is the difference between a non-secure random number generator and a secure random number generator?

Answer 1

A random number would probably mean a pseudo random number returned by an algorithm using a 'seed'.

A secure random number would be a true random number returned from a device such as a caesium based random number generator (which uses the decay rate of the caesium to return numbers). This is naturally occurring and can't be predicted.

Answer 2

It's like the difference between AES and ROT13.

To be less flippant, there is generally a tradeoff when generating random numbers between how hard it is and how predictable the next one in the sequence is once you've seen a few. A random number returned by your language's built-in rand() will usually be of the cheap, predictable variety.

Answer 3

No computationally feasible algorithm should:

• recover the seed, or
• predict the "next bit"

for a secure random number generator.

Example: a linear feedback shift register produces lots of random numbers out there, but given enough output, the seed can be discovered and all subsequent numbers predicted.

Answer 4

With just a "random number" one usually means a pseudo random number. Because it's a pseudo random number it can be (easily) predicted by an attacker.

A secure random number is a random number from a truly random data source, ie. involving an entropy pool of some sorts.

Answer 5

It probably depends on the context, but when you are comparing them like this, I'd say "random number" is a pseduo random number and a "secure random number" is truly random. The former gives you a number based on a seed and an algorithm, the other on some inherintly random function.

Answer 6

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