Create random 128 bit AES Encryption key in iOS

Question

I want to create random AES Encryption key (128 bit) in ios. I have searched in SO but I cannot find a good answer. Please give me some advice. thanks in advance.

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Answer 1

This might help

- (NSString *)getRandomKey{
    NSString *alphabet  = @"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXZY0123456789/=+";
    NSMutableString *s = [NSMutableString stringWithCapacity:20];
    for (NSUInteger i = 0; i < 20; i++) {
        u_int32_t r = arc4random() % [alphabet length];
        unichar c = [alphabet characterAtIndex:r];
        [s appendFormat:@"%C", c];
    }
    NSLog(@"%@", s);
    NSString *key = s;
    return key;
}