# Tag Info

1

If you are designing a cryptographic protocol and need to combine contributions from two different sources, the standard way is to use a cryptographic hash function to combine the two values. Basically, use $H(x,y)$, where here you use a standard way of forming a tuple of two values (if $x$ or $y$ are known to have a fixed length that's always the same, you ...

1

Given two arbitrary/random $n$-bit words, how could one best mix them to get one $n$-bit word for general crypto usages? There's no such thing as "general crypto usage". Whenever we combine two different values in crypto, we have specific properties in mind, depending on why we are combining them, and in what context. For example, if we combine them ...

3

In most PRNGs this leads to a total disaster, in particular when generator's state is bigger than the result returned as pseudo random (call to rand()). If you take Mersenne Twister with it's big period guaranteed and apply the construction you expose, as it returns 32 bit integers, eventually you will get a repeated value that was used to seed previously, ...

2

In such terms, I suppose you should to find GCD of two numbers Key1 and Key2. It seems that with big probability it will give to you one of the prime number which was generated by compromised generator. Pollard`s method is very hard, and I doubt, that you can successfully apply it in the case.

0

One thing you can do if you are not too concerned about losing some entropy is this: For the numbers 0 through 9, divide them evenly into two groups. Assign a 0 bit to any number that occurs in the first group, and a 1 bit for any number that occurs in the second group. For example: 0 = 0 1 = 0 2 = 0 3 = 0 4 = 0 5 = 1 6 = 1 7 = 1 8 = 1 9 = 1 Or you might ...

1

Proof of security: Let (x_1, ..., x_n) be the messages you caught. Let (p_1, ...) and (q_1, ...) be three streams of random messages known to both communication partners. Let these be from a true random number source generating non-autocorrelated data. Let (n_1, ...) be another stream of data from the same source. Since there is no correlation, it is ...

Top 50 recent answers are included