用C++模拟C#Random()(相同数字)

Question

有没有办法在C++中实现C#Random()类？我特别需要根据给定的种子生成相同的数字序列.

场景:我正在努力通过利用他们在C#中使用Random()来"破解"几个加密恶意软件来生成密钥.显然,只有2 ^ 32个可能的密钥,~4.3B密钥,这是可能的猜测范围.我在C#中编写了强力执行器,但无论我优化多少,它们都相当慢.我想用C++实现一个bruteforcer以获得最佳效率("更接近硬件"),因为我可以通过解密部分获得更好的速度优化(例如,AES-256通常甚至可以在未来利用GPU) ,并以指数方式获得更好的产出.

显然,随机(种子)!= srand(种子),基于不同的生成器.有没有办法在C++中实现PRNG C#用途？我显然无法修改C#恶意软件,因为已经对受害者的文件进行了加密,因此我不能只是"重写两者以使用相同的常见RNG".

Answer 1

您可以在此处查看Random(在c#中)的源代码.

Answer 2

感谢大家的回答和评论。如果其他人需要它用于类似项目，我将在此处发布我移植的 C++ 代码。它非常适合复制/粘贴，只需“翻译”几行，然后将其分解为合适的原型。确认并排生成与 C# 应用程序完全相同的数字序列。:)

随机数

#include <limits>

#pragma once
class Random
{
private:
    const int MBIG = INT_MAX;
    const int MSEED = 161803398;
    const int MZ = 0;

    int inext;
    int inextp;
    int *SeedArray = new int[56]();

    double Sample();
    double GetSampleForLargeRange();
    int InternalSample();

public:
    Random(int seed);
    ~Random();
    int Next();
    int Next(int minValue, int maxValue);
    int Next(int maxValue);
    double NextDouble();
};

随机文件

#include "stdafx.h"
#include "Random.h"
#include <limits.h>
#include <math.h>
#include <stdexcept>

double Random::Sample() {
    //Including this division at the end gives us significantly improved
    //random number distribution.
    return (this->InternalSample()*(1.0 / MBIG));
}

int Random::InternalSample() {
    int retVal;
    int locINext = this->inext;
    int locINextp = this->inextp;

    if (++locINext >= 56) locINext = 1;
    if (++locINextp >= 56) locINextp = 1;

    retVal = SeedArray[locINext] - SeedArray[locINextp];

    if (retVal == MBIG) retVal--;
    if (retVal<0) retVal += MBIG;

    SeedArray[locINext] = retVal;

    inext = locINext;
    inextp = locINextp;

    return retVal;
}

Random::Random(int seed) {
    int ii;
    int mj, mk;

    //Initialize our Seed array.
    //This algorithm comes from Numerical Recipes in C (2nd Ed.)
    int subtraction = (seed == INT_MAX) ? INT_MAX : abs(seed);
    mj = MSEED - subtraction;
    SeedArray[55] = mj;
    mk = 1;
    for (int i = 1; i<55; i++) {  //Apparently the range [1..55] is special (Knuth) and so we're wasting the 0'th position.
        ii = (21 * i) % 55;
        SeedArray[ii] = mk;
        mk = mj - mk;
        if (mk<0) mk += MBIG;
        mj = SeedArray[ii];
    }
    for (int k = 1; k<5; k++) {
        for (int i = 1; i<56; i++) {
            SeedArray[i] -= SeedArray[1 + (i + 30) % 55];
            if (SeedArray[i]<0) SeedArray[i] += MBIG;
        }
    }
    inext = 0;
    inextp = 21;
    seed = 1;
}

Random::~Random()
{
    delete SeedArray;
}

int Random::Next() {
    return this->InternalSample();
}

double Random::GetSampleForLargeRange() {

    int result = this->InternalSample();
    // Note we can't use addition here. The distribution will be bad if we do that.
    bool negative = (InternalSample() % 2 == 0) ? true : false;  // decide the sign based on second sample
    if (negative) {
        result = -result;
    }
    double d = result;
    d += (INT_MAX - 1); // get a number in range [0 .. 2 * Int32MaxValue - 1)
    d /= 2 * INT_MAX - 1;
    return d;
}

int Random::Next(int minValue, int maxValue) {
    if (minValue>maxValue) {
        throw std::invalid_argument("minValue is larger than maxValue");
    }

    long range = (long)maxValue - minValue;
    if (range <= (long)INT_MAX) {
        return ((int)(this->Sample() * range) + minValue);
    }
    else {
        return (int)((long)(this->GetSampleForLargeRange() * range) + minValue);
    }
}


int Random::Next(int maxValue) {
    if (maxValue<0) {
        throw std::invalid_argument("maxValue must be positive");
    }

    return (int)(this->Sample()*maxValue);
}

double Random::NextDouble() {
    return this->Sample();
}

主程序

#include "Random.h"
#include <iostream>

int main(int argc, char* argv[]){
    // Example usage with a given seed
    Random r = Random(7898);
    std::cout << r.Next() << std::endl;
}