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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What level of security is provided when a Feistel Cipher is used as a round function of another Feistel Cipher?
Recently, I was reading: Are there any specific requirements for the function F in a Feistel cipher?, and the answer posted mentions a Feistel Cipher named Turtle, which uses a four-round Feistel ...
user17887
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Reusing same source for single-source randomness extractor
Let $ext$ be a single-source randomness extractor which takes a $d$-bit seed
and a $n$-bit source as input and produces a $m$-bit output.
Suppose we have a source $X$ with min-entropy $k$. Is it ...
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Odds of false error detection in a randomness test using the chi-squared test?
Common Criteria classifies the requirements for true Random Number Generators, and specifies how these should be tested against failures (these can occur accidentally, or following deliberate attack, ...
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ChaCha-based Sponge PRNG fails PractRand suite
TL;DR: My simple ChaCha-based sponge PRNG is getting "unusual" evaluation from PractRand test battery pretty reliably, sometimes even within the first GB; I'm trying understand why.
I was in ...
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Algorithm used to generate a BitLocker recovery key
I know exactly how a generated BitLocker recovery key works and I can write a code to brute-force it.
How is the recovery key generated though?
I could think of some answers:
it is generated using an ...
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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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Can you rely on the permutation of a ciphertext for secrecy?
Say you have a message and you run it through an all-or-nothing transform. A transform that requires every single block in the correct order in order to recover any data. Each block is ...
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Combining multiple hash functions for HKDF
I'm trying to apply the hash function combination method described in https://eprint.iacr.org/2013/210.pdf to a HKDF PRNG construction. Thing is it needs 4 uniformly random parameters/keys chosen by ...
user56697
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Why does the update algorithm of HMAC_DRBG use two rounds?
I read this paper, which said that $\operatorname{update}(K, V, adin)$ should do two rounds as follows:
$\operatorname{update}(K, V , adin)$:
$K = H(K, V || 0x00 || adin)$
$V = H(K, V )$
If $adin ...
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Fortuna PRNG: What is the effect of the block cipher key size?
The Fortuna PRNG uses AES-256 for generating output blocks by encrypting a counter value $C$ in CTR mode using a 256-bit key $K$. For the analysis, it seems the block size of 128 is the limiting ...
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Implementation specific differences between RDRAND and RDSEED
I've read Intel's The Difference Between RDRAND and RDSEED and Intel Digital Random Number Generator (DRNG) Software Implementation Guide, but I have some open questions that are specific to usage in ...
user10496
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How to map a handful of numbers in a large range to a much smaller range deterministically without collissions
I want to map a set of long integers (say around 100 different values) that can span the entire 64 bit integer range to a much smaller range such as from 0 to 25000 deterministically with almost zero ...
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Proof-of-Randomness with an EC Public Key
I will be using a tRNG to generate EC keypairs on a Secure Integrated Controller.
I need to demonstrate I, the issuer, can not know the private key without colluding with the user to obtain it, even ...
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Strong RNG for encryption/authentation algo
I saw in the market several hardware options for creating strong RNG to produce strong KEYS:
HSM
TPM internal TRNG
Intel RDSEED (TRNG)/RDRAND
My questions are;
What is the strength/entropy ...
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1st round attack on rc4
I'm trying to implement the 1st round attack on RC4 stream cipher according to Attacks on the RC4 stream cipher. For now I am interested in section 4.2 Attack on other key bytes. It works really fine ...
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Safe p-value for NIST randomness test with small sample size
In this journal paper related to physically unclonable function (PUF) [1], the authors used NIST 800-22 test to check if the bitstreams generated by their PUFs are random, which is described as ...
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Input size recomendation of sequence for each test in NIST SP 800-22
I am using the NIST SP 800-22 to evaluate the performance of the Random Number Generator.
NIST SP 800-22 has a total of 15 tests. In each test, it has a recommendation for the size of the tested ...
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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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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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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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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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Generating sets of unreadable/secure and unique random numbers
In the process of doing some research, I stumbled across the following two claims on the PokerStars website.
We do record all of the hole cards in all real money hands. This is an
important tool ...
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ZK-proof of usage in a seed of CSPRNG
Assume a Player chooses a seed $s$ and he wants to prove that he uses it as a seed to CSPRNG function, where the seed is not public.
How can he prove it?
Thanks.
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How Are Linear Congruential Generator Multipliers Chosen?
There are several numbers that keep coming up when looking at certain random number generators, for example 6364136223846793005 is used in newer pcg-family algorithms and seems to draw it from ...
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Can Verifiable Random Functions be used to pick a random node from a pool?
Let's say that I have a decentralized system and I have a list of nodes published on a public log like a blockchain. I want a node A to be able to connect to ...
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Block Cipher vs Hash Function to build a CSPRNG
It's widely accepted that both block ciphers and hash functions are great cryptographic primitives to build a CSPRNG.
I'm thinking of creating a protocol where, provided that there is a source of ...
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Get LCG from output?
Given a standard LCG output, let's say 3 consecutive numbers, I'm wondering how I could get $a$ and $c$ if I already know $m$
LCG formula:
Sn+1 = ( aSn + c ) mod m
I've seen this posted in a lot of ...
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CSPRNG output as stream cipher
Say I want to encrypt short messages via radio to a friend. Would a series of key streams based on 36 characters (alphanumerics) generated by a CSPRNG like CryptGenRand and applied to the plain text ...
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Using a Secure RNG in Probabilistic Fair Exchange
I am attempting to implement probabilistic fair exchange described in Probabilistic Non-Repudiation without Trusted Third Party.
A secures a message using AES with 512 bit keys (in my implementation)....
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Special random distribution algorithm
I am implementing ring signatures as a part of an authorization system. Since the number of users could get high enough to make computation on end-user devices infeasible, I am thinking of "...
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Post processing method for True Random Number Generator
I am finding the post-processing method to improve the randomness of the True Random Number Generator. Especially, TRNG can pass the NIST SP 800-22 after applying the post-processing.
I tried to apply ...
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Mapping between NIST test and TRNG features
Each of the NIST tests are generally explained in Random Bit Generation - Guide to the Statistical Tests. I was wondering if some one can help me understand them better. For example, which tests show ...
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Predicting compromised OpenSSL 3.0 DRBG
The OpenSSL 3.0 rand function's DRBG uses the getrandom() system call to get 48 bytes of secure entropy from the kernel. It also ...
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Communication through shared seed in RNG
Given that there are two parties, and a process has been conducted by which both parties are knowledgeable of a shared value p, how could two parties communicate with each other over a public channel ...
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Public seed expansion for uniform reference strings
Many cryptographic protocols are parameterized by a uniformly random reference string (e.g. the commitment key for Pedersen commitments).
Our goal is to publicly generate the random values of this ...
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Concatenating RNG with PRNG
Is it secure to concatenate numbers from an RNG with numbers from a PRNG? I was thinking to throw a dice and use four outcomes to use as real random numbers, one outcome to change to the next ...
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How to create a CSPRNG seed that can be used to shuffle a deck of cards
I want to generate a seed using CSPRNG. I then want to shuffle a standard pack of playing cards (52) using said seed, however, I want the shuffle to be accurate enough that it covers all the possible ...
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Cracking a LCG with tricky parameters
I'm given three values $s_0,s_1,s_2 \in \mathbb{Z}_m$ that follows the recursion formular $s_{n+1} = as_n+b \mod m$.
I know $m$ and want to calculate $a,b$. It's easy to see that $a=\frac{s_1-s_2}{s_0-...
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Show that block cipher with CTR is a good PRNG
Assume that block cipher scheme $(KeyGen, Enc, Dec)$ is CPA-secure. Show that $CTR_{Enc_k(0^n)}$ is a good PRNG.
Counter mode works as follows:
$Y_i = Enc_k(IV + f(i))$
$C_i = Y_i \bigoplus P_i = Y_i \...
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What is the security of XORing SHAKE256_XOF with itself?
After reading "Can the xor of two RNG outputs ever be less secure than one of them?" I wondered if you can increase security of SHAKE256_XOF by using ...
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How to connect an external noise source file to openssl-fips-2.0.16
[ECDSA][ECDH]
Due to Insufficient Entropy in Operating system of MCU
=> Could not generate random number by using BN_rand() function
(security strength fail, and RAND_bytes fail)
Below is my ...
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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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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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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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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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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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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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'random' function $r_{n+1} = f(r_n)$, $|\{r_i,\forall i\}|=N$, $r_N = r_1$ where a function $g(r_k)=k$ is harder than in ECC?
Is there a deterministic pseudo random function $f$ with $r_{n+1} = f(r_n)$, $|\{r_i,\forall i\}|=N$, $r_N = r_0$, (for given random initial value $r_0$) where a function which derives the index of a ...
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Help, Feedback and Solutions to a problem on a PoC CSPRNG
Background
I do not recommend trying to roll your own crypto. This is just a for-fun PoC, which won't be used in any public or private scenario.
I am creating a PoC nearly-true random number ...
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