Questions tagged [devrandom]

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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 ...
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1answer
136 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 ...
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1answer
147 views

Feeding entropy pool with my own data [duplicate]

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 ...
3
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1answer
80 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 #...
3
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1answer
225 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 ...
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1answer
3k views

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 ...
3
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1answer
388 views

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 ...
4
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1answer
167 views

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 ...
3
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1answer
384 views

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?
2
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1answer
1k views

Can I use /dev/urandom for generating cryptographic keys? [duplicate]

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 ...
3
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2answers
172 views

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 ...
2
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2answers
219 views

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 ...
2
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1answer
1k views

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 ...