# Questions tagged [pseudo-random-generator]

In cryptography, a pseudo-random generator (PRG) is a deterministic procedure that maps a random seed to a longer pseudo-random string such that no statistical test can distinguish between the output of the generator and the uniform distribution. Pseudo-random generators have numerous applications in cryptography. For instance, pseudo-random generators provide an efficient analog of one-time pads.

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### How many 12 bit integers output are required to reverse the Mersenne Twister?

I am creating a web app that applies Python's random algorithm (Mersenne Twister) to generate random 12-bit integers. I am concerned as to how a user can predict ...
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### Would knowing the random seed help to break AES or similar?

Consider I knew the seed of the random number generator that Bob uses to send encrypted emails to Alice. Would I have an advantage in deciphering the message? Also, how does, for example, openssl ...
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### Stretching definition of pseudo random number generator

I am wondering if someone can say if the following qualifies as a PRNG. Input a random bit seed of length $n$ into the generator, and over $k$ steps the generator uses $k$ publicly known integers to ...
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### One-time pad with public key changes

Let $k$ by a randomly generated $n$ bit string, and $m$ a $n$ bit message. Then putting $c = m \oplus k$ is the one-time pad and is perfectly secure. Now assume the transmitter and receiver wanted ...
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### How to save an encryption key to a binary file to be used in NIST STS

I wrote a simple logistics function that i use for my pesudo random number generator.I want to test it's randomness so i downloaded a custom windows version of NIST STS. the program rqeuires you to ...
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### What PRG expansion factors are safe?

I'm trying to better understand the "cost" of randomness usage/generation in practice. I understand that generally, some (small) amount of "true" randomness is generated, and then a CSPRNG is applied ...
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### Why does mt19937 fail the universal test in NIST SP 800-22?

Update: with the help of @SqueamishOssifrage and @PaulUzdak, we discovered that my NIST SP 800-22 has a broken universal test. So this becomes a moot question. Check this report. It seems to sail ...
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### Building Key Streams from PRNGs

I am reading an intro book about cryptography and the author tries to explain why using pseudo random number generators is vulnerable. Given PRNG equation; \begin{align} S_0 &= \text{seed}\\ S_{...
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### Building Key Streams from PRNGs [duplicate]

I am reading an intro book about cryptography and the author tries to explain why using pseudo random number generators is vulnerable. Given PRNG equation; ...
Usually a Pseudo Random Generator is supposed to be IND-CPA secure. But apparently, it is not in some cases such as the following: A PseudoRandom Generator $G$ has expansion factor $n + 2$. Encrypt ...