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 ...

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54 views

Is my implementation of a PRG at least intuitively secure?

I've devised a PRG using Bezier curves , constructed with Bernstein polynomials, and I was wondering if you guys could help me with some suggestions or constructive criticism. Basicly I take a random ...
4
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1answer
64 views

Turning PRPs in PRGs with a counter

I am following the Coursera Cryptography I course and I have the following question, I am a bit perplexed by the statement, in week 2 lecture "What are block cyphers?" that a counter-mode PRF is a ...
2
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1answer
76 views

How does Web Cryptography API produce secure PRNG?

How does Web Cryptography API (eg window.crypto.getRandomValues) produce secure PRNG? Specifications: https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html#RandomSource-interface ...
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34 views

Feasible way to check n-dimensional equidistribution of PRNGs

I am currently gathering some test methods and test suites for random number generator qualities, and am a bit stuck at finding something feasible to test for n-dimensional equidistribution. As input ...
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287 views

Fastest random number generator

I just read High performance physical random number generator by K.H. Tsoi, K.H. Leung and P.H.W. Leong. It proposes a physical RNG of speed 400 Mbps. Is this the fastest random number generator at ...
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51 views

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 ...
3
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1answer
78 views

Cryptographic pseudo-random generation of address subsets

Suppose I have devices which broadcast, on an insecure channel, 32-bit addresses. I want to make these devices untraceable - one way to do so is to allocate for each device a distinct subset of ...
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1answer
65 views

Prefix property for variable length pseudo-random generators

I'm currently working through Katz & Lindell's Introduction to Modern Cryptography. In section 3.4.2, they introduce the definition of a variable output-length pseudorandom generator $G$. The ...
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0answers
98 views

Is G is a secure PRG?

Is the following function is secure PRG? Given F is a secure PRG and k is choosen random from key space K. $G(x) = F(k,x) \oplus F(k,x \oplus 1^s)$ My solution - $x \oplus 1^s = x'$ so G(x) ...
2
votes
3answers
154 views

How do I produce a stream of secure random numbers from AES-Counter mode?

I have just made my own program to encipher, using AES in counter mode, and have validated it using NIST data. So I know I have done it properly. I have read that AES-CTR can produce a stream of ...
2
votes
1answer
137 views

Can I make a PRNG that is secure even when state can be modified by user?

I am interested in making a PRNG which, after being initially seeded, can accept and incorporate client data as the only ongoing source of "entropy". It is not directly for a cryptographic purpose, ...
5
votes
3answers
274 views

How vulnerable is the C rand() in public cryptography protocols?

I just learned about the basics of public cryptography a few weeks ago and I am curious as to why the C rand() function should not be used for crypto schemes. For example, say I want to generate a ...
5
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1answer
108 views

Is it possible to determine or estimate the period for Blum-Micali PRG?

The Blum-Micali is a cryptographically secure pseudorandom number generator. The construction (from wikipedia): Let $p$ be an odd prime, and let $g$ be a primitive root modulo $p$. Let $x_0$ be a ...
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1answer
66 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.
2
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1answer
76 views

Generating shared secret random permutation

There are three blind card game players. Each player does not trust any other, even prejudicing other two players may not be blind, or there may be others in the room, peeking at their cards. In ...
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1answer
75 views

Reseeding a PRNG with the generated PRN

Would reseeding a PRNG with the PRN from the previous generation have any effects whatsoever on the quality of the generated numbers; if so, does this depend on the PRNG used, or are the effects ...
1
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1answer
78 views

Is script execution time a decent source of pseudorandom number generation?

This is for a PHP script for password generation. Naturally there are other things being calculated before the password is generated. But I figure the time it takes for the script to initialize and ...
3
votes
1answer
207 views

Practical (and secure) PRGs

Does anyone know if there exists a PRG construction which takes as input an (RSA-sized) integer seed and outputs a fixed number of bits? There are number-theoretic PRGs such as the RSA, ...
2
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2answers
157 views

Random numbers for Rabin-Miller primality tests

I've implemented a Rabin-Miller primality test fuction following Wikipedia and the book Applied Cryptography. Now I'm using it for generating primes with a string seed. The book suggests the following ...
3
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1answer
429 views

Java's SecureRandom & plaintext attack?

Java's SecureRandom is meant to be cryptographically secure, and I know part of that means that the output should not be usable to predict further output. Though, ...
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0answers
191 views

Random Number Generation with a Entropy pool versus Seed

To give a little background I'm currently implementing a crypto library in JavaScript. I have started porting across Linux's random number generator because its both publicly scrutinized, it is ...
0
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1answer
97 views

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 ...
0
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1answer
185 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 ...
2
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0answers
130 views

How can I construct a distinguisher given an inverter?

Let $ PRG: \{ 0, 1\}^n \rightarrow \{ 0, 1\}^{n+s}$ be a pseudo random generator and let $A$ be an inverter that runs in polynomial time, specifically: $\large \mathbb P_{d \leftarrow PRG(U_n)}[ A(d) ...
3
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1answer
203 views

How can I prove/disprove that a construction yields a secure PRG?

Let $G:\{0,1\}^{*} \mapsto \{0,1\}^{*}$ be a secure PRG. Prove or disprove that the following construction also yields a secure PRG. $$G'(k) = G(k||0),$$ where $||$ denotes the concatenation of two ...
3
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2answers
514 views

Why is sharing the seed and using SecureRandom “deterministically” so bad?

I've recently been reading an article about "using cryptography to store credentials", and I would love it someone explained this in more detail… Up until Android 4.1, Android used a SecureRandom ...
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1answer
108 views

How do I prove that this PRNG is easily distinguished from a random sequence of numbers (modulo m)?

I was studying Crypto, and this question came up. Using a PRG like the multiplicative congruence generator: $b_{i+1} = a \cdot b_i \mod m$ How do I prove that the output of this PRG, or any PRG's ...
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3answers
222 views

How to attack a fixed LCG with partial output?

To show some colleague programmers exactly how broken C's rand() is (at least on Windows) I decided to break it. So everyone knows the exact parameters, MSVC's ...
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3answers
262 views

Extracting only the entropy

(I cleaned up the question a bit, It was previously titled "extracting entropy without hashing" .. thus some of the comments / answers) I'd like to extract the entropy of data without injecting ...
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2answers
156 views

Fast post-processing for broken RDRAND

Let's assume that the Intel RDRAND instruction does not return fully random numbers, e.g. because it has been engineered with a backdoor for the NSA. If the Intel RDRAND instruction is used directly ...
2
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0answers
130 views

Integer factorization based password authentication

After looking at this security issue at DjangoProject, I started to think in a password-based authentication that places the burden of PBKDF2 (or whatever is the hashing function) on the client. So I ...
2
votes
1answer
101 views

Do any (non-hardware) RNGs exist which could be used to create an OTP for crypto purposes?

I've stumbled (jobwise) over a system where small messages (512 Bytes or less) are encrypted and decrypted using a simple XOR using a OTP. That OTP is created using a seed based on the individual user ...
2
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1answer
201 views

random number generator and seed

I'm working with openssl cryptographic libraries, I'm new to all these cryptographic stuffs and slowly I'm learning all these. I have a doubt regarding random number generator, I'm using ...
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Technical feasibility of decrypting https by replacing the computer's PRNG

Intel has an on-chip RdRand function which supposedly bypasses the normally used entropy pool for /dev/urandom and directly injects output. Now rumors are going on that Intel works together with the ...
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101 views

Why is it said that if we know few bits of pseudo random sequence we can predict the whole of it?

I am new to this cryptography and in the source from which i study it is said that if we know the first few bits of a pseudo random sequence we can predict the whole of it.How is it possible? The ...
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2answers
255 views

Why is the following RSA PRNG cryptographically secure?

One requirement states that the generator has to withstand the next-bit test. Consider the following PRNG, where we calculate next output $x_i$ via the formula $x_i = x_{i-1}^ e\mod n$. I can see ...
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1answer
96 views

Pseudo Random Generator (PRG) from Rabin function

I'm trying to make a PRG using the Rabin function. The code (in Java) I wrote to implement the function is: ...
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2answers
767 views

How does the rand() function in C work? [closed]

I want to know how rand() works (even when I don't provide any seed how it produces PRNs?) thanks!
4
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1answer
140 views

Does Linear Cramer-Shoup have pseudo-random ciphertexts?

"Linear Cramer-Shoup" is defined on pages 4 and 5 of $\:$ eprint.iacr.org/2007/074.pdf . Are the ciphertexts in Linear Cramer-Shoup computationally indistinguishable from uniform under a ...
2
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3answers
1k views

LFSR for small numbers with large periods

I want to generate a few random numbers using an LFSR. However, the LFSR output depends on the number of taps, so for a large period I use large (relative) number of bits. This causes the numbers to ...
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2answers
175 views

Pseudorandom generator and AE-secure encryption

How would you answer the following question (I have to translate it from German): The existence of a pseudorandom generator implies the existence of a AE-Secure encryption scheme (AE = ...
4
votes
2answers
957 views

Are there any standards of multi-prime RSA key generation?

FIPS 186-3 specifies a method to generate DSA parameters. Is there anything similar (official standard or widely-accepted recommendation) that shows how to generate the primes for multi-prime RSA?
3
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1answer
1k views

How to prove that the concatenation of two secure PRG is secure?

Given $G:\{0,1\}^s \rightarrow \{0, 1\}^n$ a secure PRG, how can one prove that $G'(k_1, k_2) = G(k_1) \cdot G(k_2)$ is secure ($\cdot$ means concatenation)? In other words, I'd like to show that if ...
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2k views

What is difference between PRG, PRF, and PRP

Until what I have gotten is: A PRG is generator is a part of PRF that produces pseudo-random values for the function. PRF is semantically secure and has no worries of being invertible. Fine, then ...
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2answers
262 views

Can you help me with this Random Number Generator function?

By someone's suggestion, I am posting this question from math.stackexchange.com. I want to find out a suitable function or algorithm, which can provide a random sequence like this… Input: $3$ ...
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1answer
174 views

BigInteger in Java and Randomness

I'm looking for some PRNGs and – as I have been using Java for a long period of time – I thought that the BitInteger class, together with the ...