Questions tagged [random]

The generation of random or pseudorandom data, and the use of randomness in security protocols

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Is encoding random with module insecure? [closed]

The ID library Nano ID claims that modulo based encoding (e.g. Base64) would lead to uneven distribution in the output: Uniformity. random % alphabet is a popular mistake to make when coding an ID ...
deamon's user avatar
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Can UUID v7 be treated as a unguessable, opaque identifier?

RFC4122bis specifies UUID v7, a version which contains 74 bits of randomness. Assuming I use a CSPRNG to generate the random bits: Are these UUIDs considered to be unguessable and are enough to ...
Jonas's user avatar
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Any idea on how this 36 character long string generated? [duplicate]

I have a personal id "U1KFhYtMqZhCYya6sy31PVLM8DlM5HLCkwy3", I have checked some hash functions but cannot make sure how this generated? Is this just random string generated with [a-zA-z0-9]?...
Slybot's user avatar
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Which algorithm does CryptGenRandom use on my laptop?

I have an Ideapad Gaming laptop by Lenovo, with an Intel(R) Core(TM) i5-10300H processor. On this laptop I have Windows 10 installed. To generate random numbers, I use the CryptGenRandom function. ...
Riemann's user avatar
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SecureRandom safety?

I need to randomly pick 10 numbers from 1 to 2000. It is very important that this rng cannot be predicted/hacked in any way. Would this be a safe/proper way to do it: int randomInt; SecureRandom ...
Cannon 190's user avatar
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Is using weak random numbers for the initialization vector of AES just a theoretical issue?

I'm the maintainer of pypdf, a Python library for reading/manipulating PDF documents. I recently discovered that pypdf used random instead of secrets for ... Generating the initialization vector (IV) ...
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Randomness of seeded cryptographically secure random number generator

If I generate a large true random number and I seed a CSPRNG with it, then can the output of this CSPRNG be used anywhere where there is a need for a true random number? For example, if Alice and Bob ...
rid's user avatar
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Randomly generated secrets: encoding the random bytes in base64 vs keeping them

Today this came to my attention. When generating random secrets for e.g. JWT (in node.js the most common way is using the crypto.randomBytes() method), I have noticed a lot of people save these tokens ...
Sam's user avatar
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exploiting the scenario and how to generate a secure reset password token

I am using the following line of code to create a reset password code sent to the user in her/his email. when scanned with brakeman to my ruby code, this line of code is catched and describes it as it ...
hanan's user avatar
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Is it possible to retrieve seed from a few random numbers?

Let's say I have generated 16 integers (between 0 and 128) using Python from random import seed, randint seed(1234) randoms = [randint(0, 128) for _ in range(0, 16)] If we have a rough knowledge of ...
leogarithm's user avatar
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Pre-generate random numbers or generate it on the spot

We are developing a lottery platform, and we are discussing what the best way to implement it would be. As we have it right now, the system pre-generates, using a TRNG device, all the winning numbers ...
Greg's user avatar
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Is there any encryption method that uses TRNGs?

Can we create a true random generator whose entropy source is the loss of electrical signals that a binary architecture cannot detect? If we have a system that let's say could do this, could we be ...
Furqan Tariq's user avatar
1 vote
2 answers
125 views

Random identifier vs identifier plus HMAC

Suppose I have a resource that I want to be accessible only using a specific link. I could generate a link using a 256 bit random identifier, e.g. https://example.com/aMXtSQufIxntoMSnTQGdgMfs84VzM-...
Gordon Leigh's user avatar
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2 answers
202 views

How does /dev/random not leak future bytes from old ones

I want to generate 6 random words using Wiktionary and random numbers from /dev/random. I'll get a random number with /dev/random and then use the word from that index. I know /dev/random should be ...
Xephobia's user avatar
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221 views

How do in-memory unrandomizers (like in Cheat Engine) work?

Cheat Engine is a rather known memory editing and manipulation tool for Windows. It has this feature to screw up your randomness generation, how does it achieve it? My guess would be that it makes the ...
Sir Muffington's user avatar
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Why GNU libc's salt alphabet for `crypt` is limited to ./0-9A-Za-z?

According to docs: To hash a new passphrase for storage, set salt to a string consisting of [a prefix plus] a sequence of randomly chosen characters ... and In all cases, the random characters ...
Anthony's user avatar
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Comparing HAVEGE and Jitter Entropy algorithms

How does the HAVEGE method (or rather, the specific adaption of it as used in haveged) for generating randomness from timing differ from that of the Jitter Entropy method? Is there any research ...
forest's user avatar
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Pseudorandom vs. True Random

Proper security algorithms demand true random numbers. For instance, secret keys & initialization vectors should never not be true random. However, generating numbers using Java's Random library ...
mindoverflow's user avatar
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Is it necessary to use cryptographically-secure randomness in order to create URLs for user activation?

Usually once you register in a website you need to visit a url like: https://example.com/user_activate/^random_string^ Does the ^random_string^ necessarily need to be cryptographically pseudorandom ...
Dimitrios Desyllas's user avatar
1 vote
1 answer
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Should a user refill their 2FA when they login into a different account and back?

Some of our users on our website have two or more accounts they use to log in. With each device they log in a specific device ID is generated. This device ID is stored on the device itself and on the ...
Efekan's user avatar
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Can I evaluate the quality of my OS random numbers? [duplicate]

Is there a software or website that implements tests of randomness to check if my random numbers are of cryptography quality ?
boredaf's user avatar
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2 answers
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Is "Math.random" the same as "crypto.getRandomValues" (JavaScript security)

This question may be a little off-topic, but is Math.random the same as crypto.getRandomValues? (JavaScript) Here's an example: Math.random(); // 0.11918419514323941 self.crypto.getRandomValues(new ...
Parking Master's user avatar
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How many random characters must an unguessable string contain?

I want to add a suffix to my URLs that makes them distinctive and therefore only findable by a person who knows that suffix. I considered using a UUID or hash, but these are usually very long. However,...
F.M.F.'s user avatar
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Does combining a non-cryptographically secure string with a cryptographically secure string result in a cryptographically secure string?

I'm using php, but the general question applies to any confirmed cryptographically secure pseudo-random string concatenated with a non-cryptographically secure string. I know random_bytes generates a ...
TCooper's user avatar
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10 votes
6 answers
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Can iterated hashes be used to create cryptographically secure random data from strong random seed?

I was wondering if generation of sequential hashes from random seed can be considered "random enough" to be used in cryptographic operations? By sequential hashes I mean the following: First ...
The amateur programmer's user avatar
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1 answer
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Verifying public key visually

Verifying a string of long numbers is hard (think of cert public key). I remember there is a tool to visualize this randomness into a "randomness graph" but I cannot recall what is the graph ...
tkokasih's user avatar
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3 answers
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Is a simple random+hmac session cookie breakable?

I make session cookies of form session_id+'|'+hmac_sha256(session_id, static_secret) where session_id = random_string(16 bytes) made with a PRNG (not a CSPRNG!) seeded on the server's timestamp at ...
capr's user avatar
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1 vote
1 answer
367 views

Randomness of hash of (password + suffix)

Suppose I have a password, say "thisIsThePassword". Then I have MD5 hashes of that password followed by an increasing numeric suffix: MD5("thisIsThePassword1") = ...
reed's user avatar
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How many bytes for password reset token? Should one take steps to hash or conceal raw CSPRNG bytes?

I'm trying to follow the OWASP 'Forgot Password Cheat Sheet' recommendations for password reset functionality via email. This requires my server to generate a token. OWASP says that PHP's random_bytes(...
S. Imp's user avatar
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2 answers
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Is it bad to reveal random bytes from a system?

Let's say you cat /dev/random or /dev/urandom all day from boot to system shutdown, either redirecting the output to a file, or just catting it (in a terminal, or whatever) doesn't matter. Is this ...
William Martens's user avatar
3 votes
1 answer
1k views

Is Python's `secrets` module using the same code as the `random` module?

The secrets module is marketed as a safe alternative to random for things that are meant to be secret. But what's the actual difference? Looking at their code, in some cases these libraries actually ...
random's user avatar
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1 answer
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Are weak entropy sources worth it?

I maintain an operating system that can be deployed to embedded devices with highly diverse capabilities. One of the aspects of porting the OS to a device is declaring the available entropy sources (...
Gilles 'SO- stop being evil''s user avatar
2 votes
5 answers
962 views

Attacks Relying on Poor Entropy

I'm creating a quantum random number generator as part of my thesis. As part of the research phase, I'm trying to substantiate my aspertion that encryption is significantly weakened if a computer ...
ScottishTapWater's user avatar
5 votes
1 answer
253 views

Security Implications of Caching Randomness

Is it a bad idea to cache randomness in the general case? My feeling is yes, but I'm having a hard time articulating why. Scenario: A programming language of your choice (e.g. node) uses a native call ...
vincent's user avatar
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-1 votes
1 answer
341 views

What is "environmental noise"?

I'm looking at way to generate random numbers for cryptographic purposes. More specifically, I looked at the Linux /dev/urandom function, which is considered a real random number generator. There are ...
Sam The Sid's user avatar
0 votes
1 answer
585 views

So I just got a voicemail from a random person, where it says 3 random numbers (for example 354) and then "goodbye" [closed]

So basically, i was just playing games as always, and I get a voicemail. It reads-"396 (random numbers just incase the numbers are sensitive information), goodbye" It sounds automated but i'...
Kevin Phelan's user avatar
1 vote
2 answers
264 views

How to select a random node when nodes are untrusted in a distributed network?

Assume in a distributed network, where the nodes are not trusted and are identified by their public keys, we intend to select one of them in a random process. In such a situation, all of the nodes ...
Questioner's user avatar
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Weird GET request on internet facing Nginx [duplicate]

I spun up an internet facing nginx server in AWS and the logs started showing weird get requests with a search engine's spider as user agent. 172.31.43.193 - - [19/Aug/2020:20:09:19 +0000] "GET /...
Shabin Muhammed's user avatar
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1 answer
647 views

Security of PHP's str_shuffle()

I'm doing some research on PHP's str_shuffle function, I already asked this question multiply times on StackOverflow but got no answer https://stackoverflow.com/questions/61968859/is-it-possible-to-...
user239146's user avatar
8 votes
2 answers
322 views

Randomly selected words converted into sentence. Did I lose passphrase strength or gain it?

I got 5 dice and opened EFF's wordlist, and generated a random five-word passphrase (all letters small with spaces, no punctuation) for my PC. The words were making up a meaningful scene in my mind, ...
user's user avatar
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5 votes
2 answers
3k views

Is it cryptographically safe to use veracrypt in a virtualbox virtual machine?

Does virtualbox provide enough entropy (random numbers) for the veracrypt program on the virtual machine? Is it cryptographically safe to use veracrypt inside a virtualbox in a windows 10 guest?
chanaccll's user avatar
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0 answers
415 views

Random URLs to hide assets [duplicate]

Say I own a domain name www.example.com and I'd like to host some resources on it, but being reasonably hidden from the public. Since a 256 bits has a sufficiently large entropy to prevent an ...
Arthur Attout's user avatar
3 votes
1 answer
210 views

Randomly generating invoice IDs

I'm in the process of setting up a local (i.e. offline and very limited) business, and I'm thinking of generating invoice IDs randomly to avoid the clients knowing that they're customer number #...
Hashim Aziz's user avatar
2 votes
1 answer
417 views

Did PHP's rand() get better?

I know that PHP used the system implementation for its rand() function, which is usually a weak LCG or LFSR implementation. Did this change? In case it still does, I am using Fedora 32. PHP states in ...
dmuensterer's user avatar
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0 votes
3 answers
219 views

Is a random number secure (enough) for card numbers and pins?

I've been given the task of generating some gift tokens which comprise a serial number and a pin number, analagous to a pre-paid credit card. The serial and pin will be printed on a card, with the pin ...
Greg B's user avatar
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0 answers
260 views

Generating trusted random numbers for a group?

Alice and Bob need to share some cryptographically-secure random numbers. Alice does not trust Bob, and Bob does not trust Alice. Clearly, if Alice generates some numbers, and hands them to Bob, Bob ...
Him's user avatar
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1 answer
193 views

What vulnerabilities would this type of "password manager" have?

When I was searching for a password manager to use I stumbled upon the concept of Master Password which instead of encrypting and saving your passwords, generates them by using your master password ...
user avatar
0 votes
1 answer
461 views

Does OAuth2 state parameter need to be cryptographically secure?

In OAuth2, as part of the authorization request, we generate a random string and pass it with the state parameter, so that when we get the response, we can ascertain that the response is a result of ...
Gigi's user avatar
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4 votes
1 answer
595 views

Does rngd -r /path/to/file inject into /dev/urandom in addition to /dev/random?

I'm new to the /dev/random and /dev/urandom pipes in general and have an application calling from /dev/urandom which I'm attempting to inject entropy into. I'd prefer not to change the source for ...
CoryG's user avatar
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1 vote
0 answers
110 views

Anonymous (privacy-preserving) random walk

Quoting this paper - SmartWalk (https://dl.acm.org/doi/pdf/10.1145/2976749.2978319): For graph privacy, strong link privacy relies on deep perturbation to the original graph, indicating a large ...
rshah's user avatar
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