Linked Questions

86 votes
11 answers
11k views

Is modern encryption needlessly complicated?

RSA, DES, AES, etc., all use (relatively) complicated mathematics to encrypt some message with some key. For each of these methods, there have been several documented vulnerabilities found over the ...
Ozzah's user avatar
  • 977
6 votes
2 answers
2k views

How many bits can be safely extracted from the BBS generator at each step?

The Blum-Blum-Shub generator is a deterministic Pseudo-Random Bit Generator with security reducible to that of integer factorization. Setup: Secretly chose random primes $P$, $Q$, with $P\equiv Q\...
fgrieu's user avatar
  • 141k
7 votes
2 answers
447 views

Are factorization algorithms parallelizable?

I was reading about the Blum-Blum-Shub random number generator, and its security depends on the hardness of factoring very large numbers (like many things in crypto do). I'm just wondering, if I have ...
Maestro's user avatar
  • 1,069
6 votes
2 answers
2k views

Blum Blum Shub Pseudo-Random Generator Requirements

I am trying to understand the Blum Blum Shub pseudo-random generator originally described in A Simple Unpredictable Pseudo-random Number Generator As best I can tell the requirements are: For any $...
ben rudgers's user avatar
8 votes
1 answer
635 views

How did SHA-1 'feed' Blum Blum Shub

One of the most (in)famous hardware derived random number generators was Lavarand (patent). It did it with funky lava lamps. An image of the lamps was hashed and fed into Blum Blum Shub (BBS) to ...
Paul Uszak's user avatar
  • 15.4k
0 votes
2 answers
586 views

Is BBS used for generation of keys for any modern cryptosystem?

Is there any (current) cryptosystem or digital signature or cryptographic primitive that uses the BBS PRG in order to generate its secret keys?
111's user avatar
  • 796
3 votes
2 answers
335 views

How big does M need to be in Blum Blum Shub?

I've read that Blum Blum Shub is a CSPRNG, defined by $x_{n+1} = x_n^2 \bmod M$. I didn't understand that, and couldn't find any sources on how big $M$ should be. Are 32 bits enough? 64 bits? Or are ...
Command Master's user avatar
4 votes
1 answer
341 views

Blum Blum Shub Hash

Will this algorithm make a cryptographically secure hash function? Can it be used to generate passwords? Is it secure enough for use as a MAC? Divide the message into blocks. The initial state is $h=...
user43678's user avatar
1 vote
1 answer
562 views

Why is knowing M not enough to break Blum Blum Shub?

In Blum Blum Shub, the generator is $x_{n+1}={x_n}^2 \mod M$ where $M=p \cdot q$, $p \in \mathbb P$, and $q \in \mathbb P$. Supposedly, knowing $p$ and $q$ is enough to break the system. But if I know ...
Melab's user avatar
  • 3,655
1 vote
2 answers
148 views

Rigorous practical pseudorandom generators

It is known that existence of pseudorandom generators (PRGs) is equivalent to the existence of one-way functions. In turn, the latter is an open problem. I am curious if someone developed kind of &...
Rubi Shnol's user avatar
-1 votes
1 answer
219 views

Which is the longest CSPRNG?

There are some PRNGs considered cryptographically secure. Which has the longest period among them?
IPRNG's user avatar
  • 59
2 votes
2 answers
164 views

Proper method of writing pseudo random sequences into binary files?

I am working in Python and created a B.B.S. implementation that outputs a sequence of pseudo random positive integers into a Python list. I would like to write this data to a binary file and pass it ...
user918212's user avatar
2 votes
0 answers
132 views

Rating a steganographic system using Blum Blum Shub to locate hidden bits

Currently I'm building a toy steganography system based in a web browser. Besides all the obvious issues with building a system requiring extreme privacy into a browser (this is a toy!), I was curious ...
Everlag's user avatar
  • 150
1 vote
0 answers
126 views

Pseudorandom number generators based on hard problems in mathematics

I know that Dual_EC_DRBG's security is based on the ellitpic curve discrete logarithm problem, Micali-Schnorr is based on the difficulty of factorization, and MQ_DRBG is based on multivariate ...
Melab's user avatar
  • 3,655