creation of (real or pseudo) random numbers (or bits).

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0answers
214 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 ...
3
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1answer
601 views

Good entropy source for generating openssl keys

I need to generate a CA (4096-bit RSA) and server keys for openvpn and I want them to be "top quality". Here is my plan: gather entropy from multiple sources (saving individual files): FreeBSD ...
4
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1answer
164 views

How does a backdoor in the RNG enable an attacker to break encryption protocols?

I'm wondering how a backdoor in a random-number generator (as rumored the NSA have placed), actually compromises the security of things like VPNs or TSL/SSL. What I understand is that, if such a ...
2
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1answer
831 views

What is the difference between CSPRNG and PRNG?

Is there performance differential between them? For example: we use PRNG for key generation which is very expensive and CSPRNG for IV/nonce in block ciphers which is fast? What is the difference ...
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4answers
1k views

Is a Mersenne-twister cryptographically secure if I truncate the output? [closed]

I want to create an online roulette game. Is it OK if the PRNG is seeded only once, when the user starts the game, or is it recommended to re-seed sometimes during game? Maybe just seeded once a day ...
2
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1answer
92 views

How is a PRNG used in the PGP?

I'm currently reading up on the components of PGP and I am wondering what exactly the PRNG is used for. PGP uses ANSI X9.17 and entropy from a users keystrokes to generate a temporary key. So, is ...
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0answers
91 views

$\phi$ function in Dual_EC_DRBG

I am trying to understand the operation of the Dual_EC_DRBG. I'm reading the formal specification (SP 800-90) and can't seem to find a definition of the $\phi$ function used throughout the definition ...
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2answers
230 views

How does Google's “authenticator number generator” work?

I have two-factor authentication enabled on my Google account, and I have this app on my phone which generates a number I have to type when I'm logging in to Google-Mail. But I don't understand how ...
1
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2answers
179 views

Why can we always assume that $Gen$ algorithm choose key uniformly?

Talking about a (symmetric) encryption scheme $\Pi=(Gen,Enc,Dec)$ where $Gen$ take the security parameter $n$ as input and generates a key $k$ of length $n$. Generally speaking we say that $Gen$ ...
3
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1answer
433 views

Are there any Javascript CSPRNGs? [closed]

I'm writing some software that requires the use of a CSPRNG with javascript for use in the browser and I'm wondering what libraries are available. Crypto-js doesn't seem to have a CSPRNG I can ...
0
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2answers
209 views

In Elgamal, the generator g is always quadratic non-residue modulo p where p is a safe prime and inverse of g can be also generator?

In Elgamal, the generator $g$ is always quadratic non-residue modulo $p$, where $p$ is a safe prime and the inverse of $g$ can also be generator? Can I prove it? I can't come up with it at all.
3
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2answers
593 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 ...
2
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1answer
136 views

Good Encryption Exponent

I have placed a bet that I can create a public key such that my adversary will not be able to crack (decrypt) it for at least one week. For my primes $p$ and $q$, I chose very large numbers that are ...
2
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1answer
119 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 ...
2
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1answer
280 views

LFSR using words

If I've got an LFSR, let's say a 16-bit Fibonacci LFSR as shown in the corresponding wikipedia article, which generates maximum length sequences, could I use it to create word sequences instead of bit ...
1
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2answers
487 views

Estimating random number entropy for input into 256 bit hash

Assuming a random number generation process outputs lots of numbers between 0-9. First I gathered up a bunch of the numbers, converted them to binary and created a bitmap. Not so random as you can ...
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5answers
577 views

How to prove the security of the PRNG?

Are there any realties tests or criterias that prove the security of the PRNG? What kind of tests or criteria?
3
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1answer
296 views

Is this a good entropy collector and whitening technique?

I'm just reviewing a program someone wrote to provide high quality random data using an entropy collector and a hash based whitening technique. I'll try summarize the process: Collect entropy from ...
2
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3answers
154 views

How should I interpret this note on diffusion of the internal state of a PRNG?

This question is about Tyche, a non-cryptographic PRNG. While the PRNG is not cryptographic the analysis and this question surely is heavily involved with cryptography, so I think it's on-topic here. ...
10
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3answers
387 views

How broken is a xor of two LCGs?

Suppose we define a PRG as the xor of two LCGs modulo a 64-bit prime: something like the following Python code. ...
1
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3answers
270 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 ...
2
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3answers
539 views

Using Whirlpool hashing function to encrypt data

I've read that the Whirlpool hash function can produce footprints that could be used as a pseudorandom generator. Is it "OK" to use it to encrypt some data using something like the following? ...