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Best approach for generating a non-predictable random ID?


By : JarrodD
Date : August 01 2020, 04:00 AM
wish helps you Use a normal INTEGER PRIMARY KEY column, but don't use AUTOINCREMENT (Which you usually don't want to use anyways). Then insert a row with a rowid of 9223372036854775807, the largest possible one. Further insertions without a rowid given will pick a random unused one. Details.
Example:
code :
CREATE TABLE ex(id INTEGER PRIMARY KEY, x);
INSERT INTO ex VALUES (9223372036854775807, null);
INSERT INTO ex(x) VALUES ('foo');  -- uses a random id
SELECT last_insert_rowid();


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Need for predictable random generator


By : Anas Kiswani
Date : March 29 2020, 07:55 AM
Does that help I agree with the earlier answers that real randomness in small runs of some games is undesirable -- it does seem too unfair for some use cases.
I wrote a simple Shuffle Bag like implementation in Ruby and did some testing. The implementation did this:
code :
def fire!
  hit = if @rolls >= @min_rolls && observed_probability > @unfair_high
    false
  elsif @rolls >= @min_rolls && observed_probability < @unfair_low
    true
  else
    rand <= @probability
  end
  @hits += 1 if hit
  @rolls += 1
  return hit
end

def observed_probability
  @hits.to_f / @rolls
end

Generating Predictable Secure Random Numbers


By : user1823038
Date : March 29 2020, 07:55 AM
around this issue What you want to do is get the an instance of secure random using the old algorithm using SecureRandom.getInstance.
Sample code below. You should think about weather or not this is the behaviour that you actually want.
code :
    public void example() throws NoSuchAlgorithmException {
    {
        SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
        secureRandom.setSeed(12345678L);
        System.out.println(secureRandom.nextLong());

    }
    {
        SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
        secureRandom.setSeed(12345678L);
        System.out.println(secureRandom.nextLong());

    }

}
3325995872096263519
3325995872096263519

Which approach is best at generating random numbers?


By : user2666650
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , Neither of those is very good. You want a less predictable seed (which srand/rand can't do), and a uniform distribution (which % 100 of just about anything won't do).
Instead, use the C++11 standard PRNG suite (adapted from cppreference example code):
code :
int main()
{
    // Seed with a real random value, if available
    std::random_device r;

    // Seed the default ending from good random
    std::default_random_engine eng(r());

    // Define a proper distribution that won't exhibit bias
    std::uniform_int_distribution<int> dist(0, 99);

    std::cout << "Random value: " << dist(eng) << std::endl;
}

Generating unique permutations in a predictable order with Python and Sympy


By : user2841240
Date : March 29 2020, 07:55 AM
I hope this helps you . The elements are ordered before the permutations are generated by multiset_permutations. Your result will not depend on the order of the input items.

Is this approach to generating a "random" number from a sha512 hash effective?


By : HumbleDonkey
Date : March 29 2020, 07:55 AM
should help you out The best way - as always in crypto - is not to roll your own security if it can be avoided. As your random number generator rand() is not cryptographically secure (see the Notes section). Applying a hash on it won't make this random number generator secure. Actually, it is as good as impossible to make a good RNG from a (set of) bad ones.
Instead it is much better to use openssl_random_pseudo_bytes. There is no need to perform any post processing on the bytes you get from that random number generator - at least not to add cryptographic strength.
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