Questions tagged [random-number-generator]

A random number generator is a software or hardware solution which functions as a generator of (real or pseudo) random numbers (or bits).

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273 views

Difference between Non-uniformly random and Uniformly random

I am reading up on Key Deriving Functions (KDF) and in a section of the Real-World Cryptographic book by David Wong, a comparison is being made with Pseudorandom number generator (PRNG). And one of ...
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OpenSSL and PRNG [closed]

Can a PRNG be shown to public? Are there secure PRNGs that if you dispose their structure, they still remain secure? If no, how does openSSL create its random numbers for the keys etc.?
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Mersenne twister word size and degree of recurrence combination

For a 32-Bit variant of Mersenne twister, if the outputs Should be a 5-Bit integer(word size) then what is the value of recurrence according to the k-distribution?
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Program to predict a 5-bit output from mersenne Twister random module from python

Is there a program to predict the mersenne twister random module in python for a 5-bit integer output, provided the consecutive 3994 outputs are available? The random module is not seeded so i guess, ...
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How to reproduce seeds in Random Number Generator like WELL, KISS etc

I am curious about Padding the seeds of Random Number Generator. (I am sure that terminology, padding the seeds, is not correct. If someone knows the proper word, please let me know :) ) What is ...
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Can AES fail PractRand?

Mellisa O'Neil tested Xoroshiro128+ with 512 terabytes (2^49 bytes) of data. And finally it failed. Would AES fail PractRand with enough data? When we can expect that AES will fail? Maybe with $2^{64}$...
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A source of randomness that anyone can independently, conveniently and robustly access?

Does there exist a source of randomness that anyone in the world can independently, conveniently and robustly access? For example, the 10th decimal place of the temperature in Mexico City is ...
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What are the fastest algorithms that sample from the uniform distribution?

Lots of cryptography algorithms rely on pseudorandom number generators. Sometimes, given a plaintext, you need to generate a pseudorandom number from it. What are some fast algorithms that do so? I've ...
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1answer
65 views

When not to reject a random number generator?

I have constructed a true random number generator, and I applied the NIST randomness Test Suite to its results. I have generated around 200 files with my TRNG, each being $10^6$ bits in length. The ...
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1answer
43 views

Randomness extraction on correlated data in TRNG

True random number generator (TRNG) designs I read about mostly consist of two digital stages: Low-frequency sampling (of a physical noise source) Randomness extractor The noise signal is sampled at ...
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1answer
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Randomness extraction from a Santha-Vazirani (semi-random) source

In a quest to better understand randomness extractors (in the context of TRNG post-processing), I read some papers about the von Neumann Extractor and Santha-Vazirani (SV-) sources. The von Neumann ...
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How can I recover mersenne twister when only the part of the bits?

https://github.com/tna0y/Python-random-module-cracker Here, when we get 32*624 bits of outputs from Mersenne-twister we can recover Mersenne twister. My question is when we get the parts of the bits, ...
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Can we combine two true random generators to obtain a new one?

It is well known that a true random generator exploits the randomness occurs in some physical phenomena. Also, the output of a true random generators can be either biased or correlated. Therefore, de-...
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Design an algorithm to generate random session key

good day. I am asked to design the a simple algorithm to generate random session key id of block length of 8 and change continuously every time it refreshes. Is there any simple algorithm to create ...
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Security proof for PRNG

Could you help to find an example of where the next kind of proof is performed, please? "if we can distinguish the randomly generated bits of a PRNG from a random sequence, then we can ...
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CSPRNG in Javascript?

I'm trying to obtain a random, unpredictable quite long number (± 20-25 digits) using Javascript (created by user's client) as fast and light as possible. Is this solution reliable, robust and secure ...
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Is using /dev/hwrng for raw key material secure?

Is using /dev/hwrng for raw key material secure (as long as you trust the hardware)? I tested it using the rngtest tool and it has good output.
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How to compute the dataset size required by dieharder tests?

I am trying to use the dieharder random number test suite. However, this suite requires massive amount of data (this paper claims 228GB for no rewinding for every test) for most of the tests. I'd like ...
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Mismatch between NIST SP800-90A test vectors and CTR_DRBG output

I am testing my Python implementation of NIST SP800-90A CTR_DRBG https://csrc.nist.gov/publications/detail/sp/800-90a/rev-1/final (AES-256, no df) with the CAVP test vectors (https://csrc.nist.gov/...
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Rigorous practical pseudorandom generators

It is known that existence of pseudorandom generators (PRGs) is equivalent to the existence of one-way functions. In turn, the latter is an open problem. I am curious if someone developed kind of &...
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Does watching Youtube generate entrophy

Does watching videos (either online videos such as off youtube or saved locally) generate enough (if any) entropy to create secure encryption keys? I understand that some activities such as memory ...
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Benchmark for CSPRNG as stream ciphers?

My limitation in my security protocol is that I want my RNG as CSPRNG and I also want it to be super fast. If I use Salsa20 or ChaCha or AES counter mode, I don't get the desired speed. I want my PRNG ...
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Is a LFSR sufficient for post-processing a biased TRNG?

I am building a TRNG on a FPGA based on ring oscillators. I found out that Linear Feedback Shift Registers (LFSRs) are commonly used for the post-processing of TRNGs. Here is my initial design: Let's ...
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1answer
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Which test suit is better to say if PRNG is CSPRNG:TestU01 or NIST?

Actually my concern is that I am planning to apply xoshiro256+ for implementation of stream cipher https://prng.di.unimi.it/ for my cryptographic application. It passes the BigCrush tests. Will it ...
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Distributed Random Oracle with Verifiable Shares

$Setup$: Let's assume a quorum of $n$ nodes where each have a secret share $y_i$ from a know and safe leaderless DKG protocol. Define $\mathcal{L}^i(y_i) = y$ as the lagrange interpolation for $x=0$, ...
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Is multiple encryption with stream ciphers vulnerable to meet-in-the-middle attacks?

Let's suppose I encrypt something with a stream cipher (CSPRNG) two times using two 256-bit keys and different IVs. Will I get 512-bit encryption strength?
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What is novel about Seedless RNGs?

Seedless Fruit is the Sweetest: Random Number Generation, Revisited introduces a theoretical framework for "seedless" RNGs. AFAICT, this framework injects entropy directly into the ...
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Why are $\lceil 1/\operatorname{entropy-per-bit} \rceil$ number of bits not sufficient to generate an unbiased bit?

Consider a biased RNG badrand() generating 1 with probability $0.9$ and 0 with probability $...
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1answer
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What is the NIST recommended maximum bias for random number generators?

What is the maximum bias recommended by NIST for random number generators? This answer says that it is $2^{-64}$. Is it same for all applications? Does NIST have a publication with more information? I ...
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How to combine $n$ 'less random' bits to generate one 'more random' bit?

Suppose we have a random number generator badrand() generating 1 with probability $0.9$ and 0...
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1answer
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Random number generator in C++ [closed]

I've wrote a simple random number generater in C++. Simply, I thought, the random things in software. I wrote it based on below: When an object is created on the stack, its address is random. The ...
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1answer
226 views

On the initializaton of the "xorwow" PRNG

In the original paper, Marsaglia defines the xorwow() function and gives some example values for the initial state of $x$, $y$, $z$, $v$, $w$ and $d$. But it is not ...
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Soundness of Trevisan’s Extractor Against Quantum Side Information

I wonder how sound Trevisan's extractor can be against quantum side information. I checked many papers. And all of these papers were aiming to explain how sound Trevisan's Extractor is against quantum ...
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How to get ramdom number between 1 and 2048 from /dev/hwrng?

I am (perhaps naively) evaluating the security considerations of using the following code to create BIP39 seed phrases (on a read-only and offline Raspberry Pi). Apparently, using ...
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Why VDFs need to be "quickly" verifiable?

I am very new to the topic, I found it out only today afternoon, so forgive the dumbness of the question should that be the case. I have tried to grasp the rationale of Verifiable Delayed Functions (...
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Is it guaranteed that all possible random numbers can be produced?

As far as I know PRGs get an input (seed) and generate a larger output value than the input. Therefore is it possible that some outputs will never be generated? based on the fact that input is smaller ...
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How big does M need to be in Blum Blum Shub?

I've read that Blum Blum Shub is a CSPRNG, defined by x_n+1 = x_n^2 mod M. I didn't understand that, and couldn't find any sources on how big should M be. Are 32 ...
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Why do some people believe that humans are "bad at" generating random numbers/characters like this?

I'm not even sure if they are serious, but I've heard many times that some people refuse to not only trust their computer to generate a random string (which is understandable) but also don't trust ...
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1answer
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Could a good PRNG have a long period?

I'm thinking about the evaluation of a cipher or separate cipher round as a PRNG. In general, we can encrypt consecutive natural numbers and check them with some randomness test. But PRNGs don't work ...
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1answer
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Cryptography Engineering - Design Principles and Practical Applications - Chapter 9 Generating Randomness - Section 9.4 The Generator

I'm currently reading "Cryptography Engineering - Design Principles and Practical Applications" written by "Niels Ferguson, Bruce Schneier, Tadayoshi Kohno" published by Wiley in ...
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Using raw encrypted network data for randomness

I've read that encrypted data should be, theoretically, indistinguishable from random data. Using this principle of encryption, could I combine encrypted network traffic streams to generate either a ...
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Radioactive Decay, Gaussian or Uniform?

I'm trying to understand the nature of true randomness. I'm building an RNG using a radioactive source. Basically, I'm measuring the time between consecutive decays which in theory should be ...
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1answer
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Can you explain to me how permuted congruential generator XSL-RR-RR works?

I found note about XSL-RR-RR on wikipedia: https://en.wikipedia.org/wiki/Permuted_congruential_generator But I don't understand what this means: count = (int)(x >> 122) low64 = rotr64((uint64_t)...
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Min Entropy per Bit for Trevisan's Extractor/or An Extractor

We know that: trevisan's extractor based on min entropy of the relative system. For trevisan extractor, we need source, seed, min entropy value per bit and error rate for per bit I have the code for ...
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1answer
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Differences between Extractors and Privacy Amplification for Quantum Random Generators

We know that for the last step of QRNG: we need to separate quantum and classical noises from each other so we use extractors, after extractor we need privacy amplification step. At this point: if ...
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1answer
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Dieharder How can I make my input file suitable for Dieharder?

I created my random numbers and I saved them into a txt file. My input file includes just 0 and 1. Here is the link of my file And I of course read some answer before asking that question but I could ...
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1answer
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Does piping MT19937 random stream into SHA512 make the state of MT unrecoverable in practice?

It's well known that state of a Mersenne twister is quite easy to recover after you observe enough samples. But what happens if we pipe blocks comming out of MT into SHA512 and give this as output. ...
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1answer
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Is a stream cipher and a (cryptographically secure) PRNG nearly the same thing?

If I let the authentification tag aside (which is important), encrypting with AES-GCM and a fixed key and nonce: ...
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1answer
628 views

Introduction to LLL algorithm applied to linear modular inequalities

What is the Lenstra–Lenstra–Lovász lattice basis reduction algorithm about? How is it applied to solve for $x\pmod m$ a system of modular inequalities $(u_i\,x+v_i\bmod m)<w$ for $0\le i<n$? I'm ...
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How are ChaCha-based ARC4Random CSPRNGs initialized and reseeded?

I'm doing a spare-time project to collect cryptographic algorithms, implement them, and lastly benchmark them. For the CSPRNG part, I'm evaluating NIST-SP-800-90Ar1 HMAC-DRBG and CTR-DRBG (Hash-DRBG ...

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