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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68 views

Blinding value of particular form

I'm working with an implementation that creates a blinding value for RW signatures with the following C++ code: ...
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164 views

Testing hardware random number generators? [closed]

I would like to know how to test hardware random number generators. What techniques, tools or tricks to solve the problem ? Any practical difficulties, implementation complexities etc.
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Generate random in secure message transfer

I’m doing a school assignment about secure communications between a Server and a Client. Basically, messages are exchanged between the clients and the server and these communications must implement ...
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714 views

XOR cipher Pseudo-random key strength

When implementing a XOR cipher with a pseudo-random key equal in length to the plaintext, Is there a significant difference in potential key strength between keys drawn from a pool of either 1000 or ...
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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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Bad pseudo-random number generator — any guesses?

I'm trying to diagnose a badly-implemented pseudo-random number generator. The two key features of the bit streams produced by this PRNG are: significant correlation of consecutive bits (approximately ...
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Concatenation of PRFs is PRG

$F$ be a PRF, is the following $G(x)=F_{0…0}(x)||F_{1…1}(x)$ a PRG?
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What is the advantage of guessing PRG impossible outputs?

Lets say we have a length-tripling PRG $$ G:\{0,1\}^l \to \{0,1\}^{3l}$$ What would the advantage of an adversary to guess one of the impossible outputs of G?
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Are there any universal PRG’s or PRF’s?

Leonid Levin constructed a universal one-way function, i.e. a function $f$ such that if any one-way functions exist, then $f$ is a one-way function. My question is, what universal pseudorandom ...
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PRF and deterministic polytime function implie PRG

I'm struggling while trying to resolve this exercise. I already read all questions about PRG and PRF here and some proofs around the internet but none of them helped me. let's consider a function $C$ ...
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Lehmer random number generator cipher scheme with moving bits

Let's consider linear congruential generator: $X_{k+1} = a \cdot X_{k} \mod 2^{128}$ Such that $a$ is some number which for every 128-bit input $X_{k}$ from $0$ to $2^{128}-1$ will give us different ...
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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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Is it possible to compute permutations of a sequence of bytes by using exactly one pseudo-random number?

Suppose I have a certain sequence of bytes, for example 0102F4829hex, and I can pick from a pseudo-random number generator exactly one number. Is it possible, by using exactly one pseudo-random number ...
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PRNG with onto state update function

Consider a (hypothetical) PRNG where the state update function is onto, but it is easy to find the set of preimages (so not one-way). That is, if an attacker is given the internal state of the system,...
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Proving uniform output of CSPRNG

I have a question concerning the paper by Blum, Blum, and Shub introducing the $x^2 \mod N$ Generator. It is clear that the outputs of the generator pass statistical tests for randomness: the larger ...
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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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Any formal proof or reference that pseudorandom permutation can be used as pseudorandom function

Assume that a DRBG passes all statistical tests. We use that DRBG to shuffle(Fisher-Yates) an array that contains $\{0,1,\ldots,2^n-1\}$. Now get a pseudorandom permutation $\{0,1\}^n\rightarrow \{0,1\...
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safe concating PRP and PRG

Suppose it is necessary to build a safe PRG. You have one PRP with $\epsilon = \frac{1}{2} ^ {45}$, and one PRF with $\epsilon = \frac{1}{2} ^ {55}$. There is no mathematical relationship in the PRP ...
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How are implementations of PRF and PRG via AES-CTR different?

I heard that AES-CTR can be used for implementation of PRF and PRG. What is the difference between these implementations?
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Pseudo Random Generator (PRG) not deterministic

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 ...
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How to shuffle a number between a range in a reversible manner

I have to generate identification number plates from a database ID. These ID are composed of three letters and three numbers e.g. BAC 212, I already have a function ...
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Oracle version of the IND-PRG game with q queries

Consider the following oracle-based game: $O_0$: Init: $1^n$; Query: output $y \stackrel{u}{\in} \{0,1\}^{l(n)}$ $O_1$: Init: $1^n$; Query: output $G(x)$ with $x \stackrel{u}{\in} \{0,1\}^{n}...
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Swap $x$ and $k$ in GGM construction

I'm studying the Goldreich-Goldwasser-Micali construction from pseudo-random generators to pseudo-random functions. In this specific construction, assume $G:\{0,1\}^n\rightarrow \{0,1\}^{2n}$ is a PRG,...
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Making PRFs out of PRGs

Is it possible that we take a $PRG$ $G(k)$ of stretch $n\cdot2^n$, and read its output as the table of a $PRF$ $F(K)$ with input and output size of $n$? Intuitively it sounds possible however I read ...
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Can there be a PRG $G(x)$ where at most half the output bits are 1?

Can there exist a pseduorandom generator, $G(x)$, with input length $|x|=n$ and output length $|G(x)|=2n$, where $\leq n$ bits of $G(x)$ are equal to 1 for every possible input $x$? (I.e. no more than ...
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Shuffleless PRNG function with non-repeating values?

I need a simple PRNG function of type: Integer = PRNG(n, maxval) as I would like to count from 0 to maxval, not in a linear manner, but in a pseudorandom manner where I still use every value, but ...
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Please help with this question [closed]

Please help with this question.
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PRG Theory Design

PRG theory design is something of interest to me at the moment in the security of cryptography. I am interested in learning how to come with PRGs for random functions such as $\{0,1\}^{2n} \...
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278 views

Secure pseudo-random generator

Suppose that $G : \{0,1\}^k \rightarrow \{0,1\}^{2k}$ is a secure pseudo-random generator. Describe what is wrong with each of the following attempts to build a pseudo-random generator with $k$-bit ...
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Improving on a clocked PRNG

I recently developed a PRNG from scratch with a little inspiration from the initialization function used in the HC stream cipher. The state ($S$) of the basic version is an array of 5 bytes and uses ...
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Pseudo Random Generator with fixed Hamming Weight [closed]

I'm searching for way to generate secure pseudo random sequence with a fixed Hamming weight using a seed. I found below code but I need a seed to generate a sequence ... (and need know if is possible ...
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How to generate the binary file for nist statistical test?

I Have to test the result of my newly created hash function using NIST. I downloaded the NIST and I can run the NIST on the example files given in that NIST implementation. But I don't have any idea ...
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Random number generator in a 2p2 Network

for my thesis I am trying to develop a system where nodes from a peer to peer network agree in generate a random number every tot seconds. I am stocked in this problem since almost 1 week anyone can ...
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733 views

Are there problems with short pseudo-random mid-square-like sequences?

To improve "mid-square pseudo-random number generation" in generating one million pseudo-random 128-bit numbers from a 128-bit truly-random seed, I am taking the xor of the mid-square with the ...
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easy definition of pseudorandomness

I'm trying to make some understanding of the Wikipedia definition of a pseudorandom number generator. Can someone explain the intuition behind this definition (how is this describing "seeming ...
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Relationship between a key stream having a high entropy and whether it is cryptically secure in a stream cipher

Hi i am trying to build a key stream generator for my homemade stream cipher.The key stream output has a close to maximum entropy value and a large periodicity. What does it take for this generator to ...
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Is this scheme multi-message secure? [closed]

Let $G$ be a pseudorandom generator. Is the scheme with encryption $$\text{Enc}_k(m) = s \| \left( m\oplus G(k) \oplus s \right),\quad s\in\{0,1\}^n \text{ uniformly sampled},$$ and decryption $$\...
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The probability to get a given word in a PRG

Why is the probability to get a fixed given word ina PRG which maps $\{0,1\}^n$ to $\{0,1\}^{2n}$ equal to $$\frac{2^n}{2^{2n}}$$ While the probability to choose 2n bit uniformly is $$\frac{1}{2^{2n}}?...

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