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

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375 views

Fastest random number generator

I just read High performance physical random number generator by K.H. Tsoi, K.H. Leung and P.H.W. Leong. It proposes a physical RNG of speed 400 Mbps. Is this the fastest random number generator at ...
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116 views

Standard or guidance for entropy collection

I need to write some high-level security requirements which include a random number generator suitable for use in cryptography. I don't need something very formal, this isn't a security certification ...
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238 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 ...
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514 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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230 views

Generate random number which should depend on key

i want to generate random number for example from [1..100]. The algorithm which would generates random number should work similarly like a "Linear congruential generator", like this: $X_{n+1}≡(aX_n ...
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2answers
106 views

Are LFSRs enough for this?

Consider the following experiment: Let there be a machine which runs (ie. continually clocks) an LFSR of size (ie. number of bits) $b$, having a button that, when pressed, extracts the next $t$ ...
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103 views

Trustless, Multiparty Random Number Generation

I've been having trouble with coming up with a random number generator that produces a random number between two parties. My current scheme is this: User 1 gives user 2 the hash of their randomly ...
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2answers
184 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 $Gen$ ...
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1k views

How to find generator $g$ in a cyclic group?

As generator $g$ is use in DH how to find combination of prime $p$ and $g$? eg: if we choose $p=23$ its generator is $7$ (given in book) how to find it?
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254 views

Are there Cryptography certifications variants of CISSP?

Are there Cryptography certifications variants of CISSP ( Certified Information Systems Security Professional)? Like a CISSP exams, but only for cryptography?
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75 views

Whitening and randomness extraction

The Von Neumann randomness extractor is explicitly mentioned in the randomness extractor page of Wikipedia, but strangely enough that page does not contain any reference to whitening the results of an ...
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56 views

How exactly are PRNG's used to encrypt material, and what makes one any more secure than the other?

I hope my question isn't as lazy as the title indicates. What I want to ask is how people literally integrate a PRNG with encrypting material. I wrote a silly little script in Python a while back ...
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119 views

Does it necessarily mean that an RSA moduli generated with poor randomness is not random?

In 2012 a group of researchers collected a large amount of RSA moduli and calculated their greatest common divisor in order to find common factors between them. By finding a common factor they could ...
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756 views

How can i predict the next number of a long sequence of seemingly random numbers? [closed]

How can I accurately predict the next random number between 1 and 999, given past results. I have no knowledge of the PRNG or algorithm used. How can I predict the next number of a long sequence of ...
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0answers
50 views

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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0answers
44 views

Determine the iteration times using Pollard's rho Method for factoring

Let's say, we have a large number $n=181937053$ and $f(x)=x^2+1$. And also we know that $n=12391 \times 14683$. The problem is that ,using Pollard rho method, can we find the algorithm iteration ...
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228 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 ...
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92 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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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 ...
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3answers
124 views

Security of very simple XOR with random? [duplicate]

I am currently trying to implement a very fast and simple encryption algorithm in Lua for the purpose of using it with ComputerCraft. The main problem is that bitwise operations in Lua (5.2 at least) ...
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1answer
357 views

Random Number Generator based on AES CTR

I've just about done tinkering with an open source DRBG, and I sure would appreciate a bit of advice from this community. Here's the link to the project, hosted at codeproject.com. It is written in ...
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2answers
270 views

Can you help me with this Random Number Generator function?

By someone's suggestion, I am posting this question from math.stackexchange.com. I want to find out a suitable function or algorithm, which can provide a random sequence like this… Input: $3$ ...
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2answers
159 views

Why are Fortuna entropy pools reset after a reseed?

I've implemented LibTomCrypt's version of fortuna and am wondering about the pool resetting after a reseed. In fortuna.c in libtomcrypt we have the following (which is that part that adds the entropy ...
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1answer
327 views

Is this scheme a provably fair random number generation?

I have thought up a method for generating random numbers between a client and a server which I hope is fair: The client and server decide on a range in advance, $0$ trough $n-1$. The server ...
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2answers
745 views

Are mouse movement coordinates useful as a seed for a RNG?

Is it good to use a mouse movement as a 64-bit random seed for a Pseudorandom Generator like AES in Counter Mode? Should I only need to get the X and Y coordinates of the mouse movement?
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100 views

Is it possible to calculate the 'skeleton key' for DUAL_EC_DRBG? What would it take?

According to Bruce Schneier the constants used in the spec of DUAL_EC_DRBG may be related to a secret set of numbers, that could function as a master key for ...
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1answer
66 views

If $G'(s)=G(s0^{|s|})$ and $G$ is a PRNG, is $G'$ necessarily a PRNG? [closed]

I argue it is because there should be no more correlation between the outputs $G(s0^{|s|})$ than between the outputs $G(s)$. Thus we can say the $G'(s)$ is a PRNG that satisfies $|G'(s)| \geq 4|s|$. ...
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156 views

Pseudo-random Number generation for Passwords

I am looking for a good pseudo-random number generation algorithm for passwords. My scenario is that I have to generate 5K pseudo-random bits from a user-supplied password (6 characters). What are ...
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1answer
195 views

Is there a problem with constructing a CSPRNG using MD5 or SHA1?

Is there any security concerns with building a CSPRNG using a broken hash function like MD5 or SHA1? The design is such that a CRC-like function is used for mixing entropy and MD5 is used as the ...
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1answer
34 views

HMAC_DRBG Generate Process: requesting N bytes at once different from requesting N bytes in total?

Am I correct in assuming that HMAC_DRBG would return different results if I, e.g. first request 4 bytes followed by a request of another 4 bytes instead of asking for 8 bytes at once? It seems that ...
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2answers
213 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.
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93 views

How can I generate a brief (100) stream of random numbers, not using the computer or throwing dice? [closed]

I am looking for a method of making random numbers that is off-line and is also independent of specialist equipment like a Geiger counter.
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103 views

Oracle DBMS_RANDOM algorithm?

Oracle DBMS offer builtin random number generator (pseudo to be accurate). DBMS_RANDOM is one of the available packages, it is however considered as insecure for cryptography. Do we happen to know the ...
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54 views

What's wrong with this “order-preserving MAC” function?

Please note: this is purely a thought experiment and not intended for any real-world usage! I came up with a simple function $\mathrm{OPF}$ to map the integers $[0,C)$ (where $C$ is the "ChunkSize") ...
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1answer
133 views

Cryptographic Primitive Method

Is there any cryptographic primitive bijective (one-to-one and onto) function for creating cryptographic tools like symmetric encryption/decryption, Hash code generator, MAC, HMAC and Random number ...
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597 views

128-bit Pseudorandom number Generator

Is there any 128-bit pseudorandom number generator available? I tried the Blum Blum Shub Generator, but I can't produce a 128-bit pseudo-random number. Maybe before I produce a 128-bit pseudorandom ...