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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Error running dieharder input file for rng output [closed]

I am trying to run a ascii input file but I keep getting the following error: # file_input(): Error. File type is not recognized. I'm not able to find out what ...
3 votes
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Deriving a cryptographic PRNG from a publicly random sequence

Consider a model of computation where we have a public oracle that provides access to a random sequence $R$. Given an index $i$ the oracle returns either 0 or 1, with the responses being deterministic,...
3 votes
1 answer
857 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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Proof for embedded composition of PRG's

I have two secure pseudorandom generators, $G_1 : S\rightarrow R, G_2 : R\rightarrow T$. Now I need to prove that the PRG $G_3(s) = G_2(G_1(s))$ is secure. I figured that I would construct two ...
2 votes
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Inefficient double-lengthening PRG

I'm trying to prove that an inefficient double-lengthening PRG exists, i.e. construct a PRG $G: \{0,1\}^n \rightarrow \{0,1\}^{2n}$ My current approach is to bound the number of poly-time non-uniform ...
17 votes
5 answers
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Is a PRG more costly than AES or any other encryption standard?

I know that there are many encryption standards that take a key and sometimes an IV to produce a cipher-text (the most prominent one is AES). These standards usually involve many rounds of addition ...
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Reversing a Floored Xorshift128+

We suppose that we have N consecutive numbers generated by JavaScript using: math.floor(math.random()*multiple), knowing that ...
1 vote
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Let $l' > l > 0$. Construct a PRG that would transform any PRG of stretch $l$ into one of stretch $l'$

The way I understand this question is that we have a secure PRG G: $\{0,1\}^\lambda \rightarrow \{0,1\}^{\lambda + l}$, and we want to use it to make a secure PRG G' : $\{0,1\}^\lambda \rightarrow \{0,...
1 vote
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Relation between seed entropy of a CSPRNG and the output entropy

Since Linux 5.18, the internal state of the ChaCha-based CSPRNG is a 256 bits (32 bytes) BLAKE2s hash. There is also a fast key erasure mechanism which reseeds the CSPRNG every minute (source). I know ...
2 votes
1 answer
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Interpretation of the Result of Dieharder Battrery of Tests: Very High p-value Result in rgb_lagged_sum Test in Dieharder Results in "WEAK" Assesment

I'm currently testing the randomness of using SHA-256 in Hash_DRBG mechanism based on this research. The parameters used in the testing are the default parameters, except for when the PRNG fails a ...
2 votes
1 answer
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How many encrypted messages can we know, so that scheme is secure?

Let $G$ be a secure PRG and let $s$ be a private key. We can define $\mathrm{Enc}(s,m) = G(s)\oplus m$. As long as we know only one encrypted message this scheme is secure, since $G(s)\oplus m \sim r\...
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Custom linear random number generator

I've made an implementation of a linear RNG. It has two constants: b and p. Every time new value of ...
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Possible MAC design

The problem Let the following be a family of PRF functions with key length $2\lambda$ $$\mathbb{F} = \{F_k:\{0,1\}^n\rightarrow\{0,1\}^n\}_{k\in\{0,1\}^{2\lambda}}$$ Assuming one way functions exists, ...
3 votes
3 answers
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Where are TRNGs an absolute need?

Are there situations currently where a PRNG just will not do? Are there current situations where only a TRNG will be useful? What about if someone uses a cryptographically secure PRNG? What is the ...
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Is the following hash function construction collision resistant?

The problem Let the following function be a collision reisistant hash function $$H=\{H_s:\{0,1\}^{2n} \rightarrow \{0,1\}^{n} \}$$ Let the following function be a PRG $$G:\{0,1\}^{n+1} \rightarrow \{0,...
2 votes
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Randomized functions cannot increase statistical distance

In these lecture notes instructor Chris Peikert states the following lemma without a proof Let $f$ be a (randomized) function on the domain of $X$, $Y$. We have $\triangle (f(X), f(Y)) \leq \...
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1 answer
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My new PRNG (PaulssonSponge) with dieharder tests

I run an open source project implementing some RipeMD and SHA hashes, one day I got nerdy and threw together my own Sponge function. I have now tested it with the dieharder 3.31.1 test suite. Is it ...
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1 answer
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Discrete Fourier transform (Spectral) test

I am designing a pseudo random bit generator (PRBG) and I am using the NIST SP 800-22 suite to analyze the random characteristics of my PRBG. It turns out that my PRBG passes 14 out of 15 tests, and ...
9 votes
4 answers
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Fast cryptographic hash function for short inputs

I am looking for a cryptographic hash function optimized for speed on short inputs, in order to implement a pseudorandom generator with expansion factor 2 (e.g. takes 16 bytes of input and outputs 32 ...
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1 answer
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How do bad actors manipulate game results in real time within 'provably fair' gaming systems?

Ive been assigned research involving online gaming companies and their use of cryptographic algorithms to produce 'provably fair' results. The largest player in the industry uses a method involving a ...
3 votes
1 answer
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RSA/ ECC keygen HW vs SW

i have a pretty straightforward question but i can’t seem to find an answer : Regardless of the physical protection provided by an HSM or TPM or any hardware cryptographic key storage system, are keys ...
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Article explaining Fortuna algorithm

Does anyone know an article that explains Fortuna algorithm for people without cryptographical background? If not, I would like to have an explanation because I don't manage to understand it.
4 votes
4 answers
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Given PRNG $G(s)$, why is $G(s) || G(s+1)$ not a PRNG?

I have given a pseudorandom Generator $G(s)$, $|s|=n$ whose expansion $l(n)$ is $>2n$. I also know that $G^\prime(s) := G(s_1,\ldots,s_{\lfloor\frac{n}{2}\rfloor})$ is a pseudorandom generator. Now ...
1 vote
2 answers
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Should I Test A PRNG Using A Fixed Entropy Source For Its Seed?

I want to test a C implementation of Hash_DRBG—which test_demo.c file I will modify to produce random binaries indefinitely to STDOUT as to be used by piping its output—using DIEHARDER for a research. ...
2 votes
1 answer
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Consecutive ones in a PRG

I'm trying to solve this problem. I tried this. Consider distinguisher $D$ such that $D(c) = \begin{cases} 1 & \text{If there is at least $2\log_2n$ consecutive 1's} \\ 0 & \text{o.w.} \end{...
1 vote
2 answers
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Suppose $F_s$ is a PRF. Is $F'_s(x)=F_x(s)$ also a PRF?

Suppose $F_s$ be a family of keyed pseudorandom functions. Define $F'_s(x)=F_x(s)$. Is $F'_s$ a family of pseudorandom functions? It seems false but I am able to give a proof assuming $F$ is ...
1 vote
3 answers
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Is it possible to compress a random sequence with high entropy?

I have an algorithm that generates a pseudorandom sequence with a length of 100k and high entropy. I would like to check the quality of its randomness. So, I used a popular software program to ...
0 votes
1 answer
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KangarooTwelve based Random-Access PRNG

Can the KangarooTwelve Keccak-p[1600,12] be used to create a CSPRNG in which there is random access to an element (or a small group of outputs) of the generated list (instead of sequential generation)?...
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Security of the trivium stream cipher

So I've been trying to implement a Non-Deterministic RBG based on randomness polling from non-hardware sources (nothing novel, just a side-project). Since collecting entropy and further conditioning ...
4 votes
3 answers
659 views

Can we convert a pseudorandom function (PRF) to an Oblivious PRF (OPRF) through an Oblivious Transfer (OT) protocol?

I'm a software engineer, so I generally think in building blocks. And I'm not so familiar with the Math notation in Crytography, so I'll stick with function calls and function blueprints (which I ...
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Proving that a PRG is insecure

I'm trying to show that the PRG $G$ defined as below is insecure for any binary matrix $A$. \begin{align} A&: m\times n& (n < m)\\ s&: n\times 1\\ G&: \{0, 1\}^n\rightarrow\{0, 1\}^{...
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If G is a PRG, is G' necessarily a PRG?

Given: A function $$G: \{0,1\}^{3n} \to \{0,1\}^{6n}$$ which is known to be a secure Pseudorandom Generator (PRG). A derived function $$G'(x_1 \| x_2) = G_b(x_1\|0^n\|x_2), \text{ where } x_1, x_2 \...
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1 answer
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Does ISAAC really guarantee a cycle length of at least 2**40?

I just noticed that the FSE 1996 conference paper which defines ISAAC mentions a counter variable cc. This variable is said to be the reason why ISAAC has a ...
1 vote
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Pseudo random generator notation

So I'm reading this article where they talk shortly about pseudo random generators where I'm not quite familiar with some of the notation. They call $\lambda$ the security parameter. "...
2 votes
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Is ISAAC+ actually an improvement over ISAAC?

I just tried to implement ISAAC from scratch, using the Jean-Philippe Aumasson paper from 2007 as a reference. This paper gives a definition of the original ISAAC algorithm as well as the improved ...
4 votes
1 answer
1k views

Why do Mersenne Twister use Mersenne prime but not regular prime numbers

I'm trying to figure out why Mersenne Twister use exactly Mersenne prime numbers but not regular primes. What makes Mersenne prime numbers more appropriate for this role than regular primes?
1 vote
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Trouble interpreting CTR_DRBG test vector results

I've implemented a CTR_DRBG random number generator according to NIST SP 800-90A Rev. 1 and I am now testing it with test vectors provided in NIST CAVS 14.3 (drbgvectors_no_reseed\CTR_DRBG.txt). ...
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Distinct sequences in a Fibonacci LFSR

How many distinct sequences can a $128$-bit Fibonacci LFSR (considering $4$ taps set for the maximum period) generate? Will all $2^{128} - 1$ distinct seeds produce distinct sequences? Also, let's say ...
1 vote
1 answer
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Can this algorithm be called a RNG?

So I developed this algorithm as RNG, although it looks random to me, I wanted to know the opinion of more experienced persons in the topic. ...
0 votes
2 answers
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From Entropy's perspective how Encryption affects a Message?

How Ciphers, specifically, Substitution Ciphers and Transposition Ciphers manipulate the Entropy of Plaintext w/wo the aid of Entropy Source? Reversely, how Decryption manipulates the entropy of ...
5 votes
1 answer
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Cryptanalysis of the GOC

The GOC (Générateur d'Octets Chiffrants, Ciphering Byte Generator) is a PseudoRandom Generator that was used during the late 20th century for content encryption in pre-internet Videotex terminals, ...
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1 answer
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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, ...
2 votes
2 answers
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How to generate n unique numbers from the output of a hash function?

What would be an easy way to use the hexadecimal output of a hash function (like md5) to generate n unique numbers from, say 0 to 15. Of course I could generate n ...
27 votes
10 answers
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Can an AI really generate random numbers?

I asked an AI the following question: Can you provide me with random numbers of 30 digits in length? And then the AI has generated these numbers for me. ...
2 votes
2 answers
530 views

What is the difference between a seeded RNG and an XOF hash?

Suppose I have some ZK proofs that were turned non-interactive using Fiat-Shamir heuristic. So I need to generate the challenge value deterministically using some data shared between the prover and ...
0 votes
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Output a pad (un-keyed, variable length) from an input seed (fixed value for same seed)

I want a function $y = f(x, len)$: $x$ is the seed. $y$ is the output. $len \in \mathbb{Z^+}$ is the length (bytes) of $y$ Select a seed string $x$ to generate a string $y$. For each same pair of $x$ ...
2 votes
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Deterministically secure PRG from deterministically secure OWF

Consider the construction of "A Pseudorandom Generator from any One-way Function" [HILL99] in Hastad et al. One way to proof pseudorandomness of this construction is by contradiction. That ...
4 votes
2 answers
144 views

Is there a standard for LFSRs to test against for use in a stream cipher?

I am trying to implement a stream cipher that uses an LFSR PRNG. I have found resources online that give good primitive polynomials, but I am struggling to find resources with the initial states as ...
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Can I skip ahead with a quadratic congruential generator?

I have a congruential generator where $$ r_{n+1} = r_n^2 - c\;(mod\;p) $$ known $r_0$, $c$ and $p$ can i get $r_n$ without having to compute all the previous values?
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1 answer
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RFC: Approach to CSPRNG

I've been experimenting in python with different approaches to cryptographically secure pseudo random number generators, comparing them using the NIST testsuite implemented by https://github.com/...

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