在iOS上使用C ++获取加密安全随机数 [英] Getting cryptographically secure random numbers in C++ on iOS

问题描述

我正在开发一个用Objective-C和C ++编写的iOS应用程序。在C ++部分，我需要加密安全随机数。

I'm working on an iOS app that is written in Objective-C and C++. In the C++ part, I need cryptographically secure random numbers.

1. 据我了解iOS安全模型，没有办法直接访问 / dev / random 。这是正确的吗？

获取安全随机数的官方方法是 SecRandomCopyBytes 。遗憾的是，这是一个Objective-C接口。有没有办法从C ++使用这个接口，理想情况下不使用Objective-C ++？

The official way to get secure random numbers is SecRandomCopyBytes. Sadly, this is an Objective-C interface. Is there a way to use this interface from C++, ideally without resorting to Objective-C++?

还有 arc4random ，但我不情愿现在使用任何基于RC4的东西...

There's also arc4random, but I'm reluctant to use anything that's based on RC4 nowadays...

推荐答案

获得安全随机的官方方法数字是SecRandomCopyBytes。遗憾的是，这是一个Objective-C接口。有没有办法从C ++使用这个接口，理想情况下不使用Objective-C ++？

The official way to get secure random numbers is SecRandomCopyBytes. Sadly, this is an Objective-C interface. Is there a way to use this interface from C++, ideally without resorting to Objective-C++?

SecRandomCopyBytes 是一个C API。从C ++中使用它没有问题。

SecRandomCopyBytes is a C API. There is no problem using it from C++.

这是一个完整的例子。不需要ObjC ++，即使使用花哨的 vector ，还有什么可以展示它的全部C ++。显然你可以使用 malloc 。

Here's a full example. No ObjC++ required, even using fancy vector and whatnot to show it's all C++. Obviously you could just use malloc.

#include <iostream>
#include <Security/Security.h>
#include <vector>

int main(int argc, const char * argv[]) {
    const int length = 20;
    std::vector<uint8_t> randomBytes(length, 0);

    int rc = SecRandomCopyBytes(kSecRandomDefault, randomBytes.size(), &(randomBytes[0]));
    if (rc != 0) {
        std::cout << "Failed: " << rc << std::endl;
        return 1;
    }

    for (int i = 0; i < randomBytes.size(); ++i) {
        std::cout << std::hex << +randomBytes[i] << " ";
    }
    std::cout << std::endl;

    return 0;
}

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