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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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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26 views
Understanding the Inner State of a RNG
Based on the BSI evaluation criteria for quality of deterministic random number generators:
K4 – It should be impossible, for all practical purposes, for an attacker to calculate, or guess from an ...
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1answer
119 views
Reverse Java seed using outputs generated from nextInt(6)+1
Given a set of numbers within the range of 1-6:
[3,4,3,4,5,6,2,3,1,5,2,3,6,2,2,3,3,6,6,4,5,2,5,3,5,2,4,4,2,6,3,6,1,5,1,3,6,1,1,2,2,4,5,3,1,2,3,4,4,6]
generated using Java's nextInt(6)+1, is it ...
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Fisher Yates on “faulted” random number generator cryptanalysis
For the sake of curiosity and fun, i have implemented a C# program that operate as deck dealer on 40 cards deck (following the Fisher Yates shuffeling algorithm https://en.wikipedia.org/wiki/Fisher%E2%...
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192 views
Why is breaking the Blum Blum Shub PRNG not an undecidable problem?
The Blum Blum Schub (BBS) pseudo random number generator (PRNG) is defined inductively by
$$
x_{i+1} = x_i^2 \mod N
$$
to generate the bit sequence $b_0b_1b_2...$ where the bits are taken to be the ...
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1answer
58 views
Is it secure to repeatedly rehash a digest to extend the digest length?
Upon reading through the source code of Rainbow, a post-quantum signature algorithm, I found a hashing function that, using SHA-512, produced a variable length digest.
This was achieved was by ...
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What issues are there while using Linux's /dev/urandom for generating cryptographic keys?
As of Linux 5.1 the /dev/random no longer uses the blocking pool. There is a talk about the change on the page Removing the Linux /dev/random blocking pool
I ...
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46 views
Lehmer random number generator cipher - looking for differentials
I'm looking for differentials in my kind of toy encryption scheme. I can't find any.
Let's consider linear congruential generator:
$X_{k+1} = a \cdot X_{k} \mod 2^{128}$
Such that $a$ is some number ...
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1answer
67 views
The Rationale behind NIST's counter/LFSR recommendation on deterministic IV constructions on SP 800-38D
The NIST has a "SP 800-38D: Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC". This guideline is a base for AES-GCM from definition to security ...
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What is the advantage of adversary if the random number repeats?
In proof of CPA-security of encryption scheme $(r, F_k(r)\oplus m )$
where:
$F_k$ is a keyed function
$r\in_R\{0,1\}^n$ is a random number,
on page 85 of Introduction to modern cryptography we have
...
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1answer
60 views
Getting a random number on an STM32L0x1 device for SRP6a
I'm trying to get a random number for a STM32L0x1 MCU to use it in protocol SRP6a.
(I know that there are MCUs with an embedded hardware random number generator. But it would cost twice as much as the ...
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1answer
42 views
Why does l'Ecuyer reject p-values close to 1?
When applying several tests to a given generator, p-values smaller
than 0.01 or larger than 0.99 are often obtained by chance even if the
RNG behaves correctly with respect to these tests (such values ...
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56 views
On the Acceptability of a Naive Pseudo Random Number Generator
My question is probably both philosophical and technical.
Background
I was developing a CSPRNG, and I needed to shuffle the bits in one step in the middle of the algorithm - any naive shuffle would ...
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Why is the output of a True Random Number Generator (TRNG) insecure after it has been compressed?
I came across the following statement regarding true random number generators (TRNG):
A “P1 medium” [AIS31] true random number generator (TRNG) may not be directly used due to cryptographic reasons. ...
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(RNG) For the Middle Square Method, is there a table of periods for various seeds?
I'm interested in the properties of the original middle square method as articulated by John von Neumann and in particular in the relation between seed value and its period length (in cases where the ...
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On The Next Bit Test
I would like to know what $O(v(n))$ really means in detailed and simple words please.
I found it everywhere in the literature I am reviewing but I cannot find what the intuition of it (especially if ...
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1answer
79 views
Using AES-CTR as a PRNG
AES-CTR is not considered as a CSPRNG, why ?
Is it unsecure to use it when a password is hashed with Argon2id to produce the seed to generate all random data needed for an end-to-end encyption system ...
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RNG and Mersenne twister learning resources for the amateur
I am a complete amateur in the area of random number generators. I would appreciate resources to begin learning.
Also I would also like to learn about Mersenne twister. Resources that are easy on the ...
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1answer
82 views
What quality of randomness is needed for randomized side channel countermeasures?
Using per-operation randomness is a popular and effective way to protect cryptographic implementations against side-channel attacks, e.g. using Shuffling (randomizing the processing order eg for AES ...
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146 views
Is random.org truly reliable?
Can someone help me in gaining an understanding of the reliability of random.org being used by a University to select student applicants to extend invitations to?
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1answer
147 views
Is it possible to create a 128-bit UUID from a weak entropy source?
I am looking at a seemingly popular piece of JavaScript code to generate a UUID which is supposed to be a 128-bit number:
...
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2answers
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What's the name of this random number generation algorithm?
I'm looking for the name of an RNG method or algorithm, described below. Combining multiple results of a non-uniform random number generator can produce a more uniform result. It seems like this would ...
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81 views
RNG to hide some bits
Suppose I have a sequence of bits of length M. I need to hide N out of M bits (hiding means forcing them to be 0) using RNG with a key. How I can relate the output of RNG to the number and positions ...
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1answer
128 views
Breaking a Mersenne-twister RNG with unsequential outputs
Pardon me for this newbie-ish question. I'm still a novice in cryptography . I have an application that outputs random numbers from 0 - 12 (endpoints inclusive) unsequentially (some outputs are thrown ...
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CSPRNG for Contract Bridge (RAND_MAX = 0xAD55E315634DDA658BF49200)
Some background information:
In contract bridge, there are 0xAD55E315634DDA658BF49200 (just under 2^96) possible bridge deals. Since the 1990s, bridge deals for major tournaments were generated on ...
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42 views
Understanding a claim made by NIST SP 800-22 on the possibility of calculating $\beta$, the probability of error type 2 in a hypothesis test
NIST SP 800-22 on page 1-4 (that's page 16 of the PDF) states the following. Pay attention to the bold passages. (Emphasis are mine.) Are they true?! Can you advise?
One of the primary goals of ...
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7answers
6k views
Can I encrypt a message by swapping bits in the text?
I have tried out an encryption method, in which I swap bits in the text.
The text length is N bit, then I generate several random number pairs in the range 0..N-1, as [n,k] pairs. After that, I swap ...
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1answer
625 views
Practical sources of entropy on an Android device?
What Android API's can be used a practical sources of entropy ?
Given the requirement of sourcing entropy on the phone for purposes of seeding a PRNG, what are good options ?
Edit:
I have a hard ...
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1answer
86 views
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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1answer
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Allowing third party to verify and/or replay a draw
I’m not an expert in crypto, and I would like to design draw system (like a lottery, but choosing one of the participants), the most open possible, allowing a third party to verify the data/draws, and ...
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34 views
When will the random bit sequence start to repeat in pseudo random number generator
Let's say we have the Blum-Micali pseudorandom number generator.
from wikipedia:
Let $p$ be an odd prime, and let $g$ be a primitive root modulo $p$.
Let $x_0$ be a seed, and let $x_{i+1} = g^{x_i}\ ...
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2answers
69 views
Extracting Randomness from a Poisson Distribution
I'm working on a quantum random number generator based on the shot noise of CMOS camera sensor. Shot noise in an image is caused by the variance of the number of photons hitting the sensor per unit of ...
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519 views
Is it possible to construct a PRNG where the output numbers have a certain distribution of hamming weights?
I am in need of a non-uniform random number generator where each n-bit output has a hamming weight with a certain binomial distribution.
For example, I would like a non-uniform PRNG which generates ...
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1answer
99 views
Is it possible to predict a randomly generated BigInteger that uses Java's default Random library?
I've seen it posted on different forms here and here that explain how java.util.Random library uses a linear congruential pseudorandom number generator which can be ...
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1answer
87 views
Randomness extractors from Bourgain’s breakthrough- applications?
Some exciting progress to pure mathematics is due to Bourgain
Springer - Multilinear Exponential Sums in Prime Fields Under Optimal Entropy Condition on the Sources
with applications to randomness ...
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Linear approximattion of $(x+y) \bmod 2^n$ in FSM of SNOW 2.0 where $x,y$ in $F_{2}^n$
I would like to understand the linear approximation of $(x+y) \bmod 2^n$ by linear masking method in the paper refereed ""Improved Linear Distinguis'hers for SNOW 2.0" by Kaisa Nyberg and Johan Wall´...
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1answer
90 views
Pseudorandom number generation predictability
Can you expect with certainty that any pseudo-random number generator will produce the same stream with a shared seed?
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1answer
111 views
Construct a specific length-doubling pseudorandom generator from a length-doubling pseudorandom
Let $G$ be a length-doubling pseudorandom generator (i.e., for any $n\in \mathbb{N}$ and for
any $s\in\{0, 1\}^n$ it holds that $G(s)\in\{0, 1\}^{2n}$). Can you construct a length-doubling ...
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3answers
130 views
Why can a symmetric encryption algorithm be considered a pseudo-random number generation algorithm?
I have a question from my teacher: "Why can a symmetric encryption algorithm be considered a pseudo-random number generation algorithm?
Can anyone explain it to me?
And sorry if my english is not ...
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A website that identifies an RNG from its output
This happened during a discussion of RNG entropy, and the difficulty of verifying the level of entropy in a long sequence of bits (e.g. a private key.)
A colleague of mine told me about a website ...
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1answer
81 views
If ChaCha20 is being used just as a CSPRNG, is nonce needed?
I'm planning to use ChaCha20 just as a CSPRNG. Key is random (taken from strong initial entropy source) and will be constantly replaced via DJB's fast key-erasure scheme. What should I use as the ...
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Why is Math.floor(Math.random()*9000) not secure in JavaScript?
I heard that one can predict the output from Math.Random() of JavaScript, but another day I had an idea to combine Math.random() ...
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1answer
276 views
How to get the original list back given a shuffled list and seed?
Say I have a shuffled list that was shuffled in Python using random.shuffle(). The shuffling was performed using a seeded random number generator. Is there a way I ...
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1answer
769 views
RFC6979: error in reference implementation?
If I correctly understand RFC 6979, there is an error in the ref implementation section 3.2.
In the step H2, RFC specification says
...
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2answers
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How to analyze the off-by-one error's impact on the entropy of the result?
I'm reading Jean-Philippe Aumasson's book Serious Cryptography to learn more about cryptography. On page 37, the author gives an example of Cryptocat's off-by-one error in its PRNG implementation in ...
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1answer
88 views
Mathematical proof or any reference of “Deterministic random bit generator cannot produce more randomness than the randomness of seed”
The heading tells everything. Any proof or any kind of reference is welcome regarding this:
Can we get more randomness from a deterministic random bit generator than the entropy that we feed to the ...
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1answer
124 views
Murder Mystery Party
For a "Murder Mystery Party", one person is chosen anonymously to be the murderer
(i.e., only the murderer knows who the murderer is) by shuffling cards with
everyone randomly taking a private card (...
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1answer
214 views
Dieharder input file with a sequence of only binary numbers
I have a RNG producing sequences of binary numbers, ad I would like to run Dieharder test using them as an ascii txt input file. However I haven't been able to do it properly. Should I use a header ...
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Mathematical definition of deterministic and non-deterministic random bit generators
Can anyone give the mathematical definition of deterministic and non-deterministic random bit generator?
Providing a reference will also be very helpful.
