IT Security Stack Exchange
IT Security Stack Exchange

Questions tagged [devrandom]

13 questions
9
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1 answer

Is reading from /dev/urandom on macOS Catalina a safe way to produce cryptographically secure data?

I'm reading a lot about entropy on macOS... I know it doesn't use Yarrow anymore as per this FIPS 140-02 doc a NIST compliant DRBG. I read a lot: https://github.com/briansmith/ring/pull/398 How can I measure (and increase) entropy on Mac OS…
Woodstock
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4
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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 this application, but an additional process calling…
CoryG
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4
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An alternative for /dev/urandom

I like to overwrite my harddisk with random data. Since /dev/urandom as source is too slow to overwrite a large amount of data in a reasonable time, I'm looking for a good alternative. These two options meet my speed requirements: (1) openssl with…
dev_new
4
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1 answer

Is pressing random keys a secure way to seed a key generator?

There's a couple of programs that I've been using recently that ask you to type random keys as a source of randomness to seed an RNG for key generation. Is this considered a good practice still, or is it better to rely on /dev/urandom and company as…
Stack Tracer
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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 #00000001 (and because I prefer something like #30549805…
Hashim Aziz
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Would `cat /dev/random` be a denial of service to any other users of `/dev/random`?

As in the question. Wouldn't cat /dev/random decrease the entropy estimate until it blocks, which forces the random device to block for all applications on the current system?
oink
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3
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Is it still secure if a cryptographic key generated with OpenSSL while a backdoored HWRNG used?

Assuming I plugged a HWRNG in to my Linux machine, use OpenSSL to generate a RSA key pair and encrypted some text with AES. Later then, a researcher posted the HWRNG was backdoored. Should I consider those key are safe to use since Linux kernel…
Hartman
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Can I use /dev/urandom for generating cryptographic keys?

I need to generate thousands of cryptographic keys. Can I just read the bits from /dev/urandom on a Red Hat system, or do I need to run it through a PRNG? My understanding is that /dev/urandom should be good enough, but I've had some push-back, so…
vy32
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Token generation and random numbers

I have a swift server, where currently authentication is handled through a simple email+hashed password combination. I want to replace this with an access token ( + expiration ) so I can remove the storage of email/password on the end-users device…
Antwan van Houdt
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Windows .NET equivalent to Linux /dev/random

Is there a pseudo device-based random data stream/file that can be used in Windows .NET programming in the same way as /dev/random can be read and used as a source of random values on Linux based systems? I’m not asking whether .NET can provide a…
David Scholefield
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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 insecure, or a bad idea? If so, why? Revealing…
William Martens
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Feeding entropy pool with my own data

Let's state that I have a huge bunch of truly unpredictable random data in file "random.bin". The random data has been created outside of my system and has been securely transfered into my system. Questions: How could I feed this file to the OS…
Algiz
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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 others number generators such as the glibc rand()…
Sam The Sid
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