How to get high-quality random numbers on iPhone or iPad?

Question

I know that arc4random () is considered one of the best randomness options. But still, he tends to give obvious duplicates and repetitions several times.

I was thinking about using accelerometers to add some real randomness to the arc4random output. Before I spend several weeks developing a better solution: what other solutions are available?

Answer 1

In response to your real question, if you want something better than arc4random (), check out

mersenne twister

which in certain ways is "better." Hope this helps!

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Answer 2

. " " ; arc4random /dev/urandom, .

Answer 3

( arc4random ), , , . , .

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Answer 4

"-" ... arc4random(), . , .

:

if (!self.dictionaryValues) {
[self loadList];

} else {

NSMutableDictionary *unusedValueList = [[NSMutableDictionary alloc] initWithDictionary:self.dictionaryValues];

int random = arc4random()%[self.dictionaryValues count]; // note, crashes on nil;
int i=0;
for (NSString *key in self.dictionaryValues) {
        i++;
        if (i == random) {
            NSLog(@"MATCH! on key=%@", key);
            [unusedValueList removeObjectForKey:key];
        }
}
self.dictionaryValues = nil;
self.dictionaryValues = unusedValueList;

}

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Answer 5

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http://thedailywtf.com/Articles/More-Entropy,-Please.aspx