在c++中模拟c# Random()(相同的数字)

本文关键字：数字 Random c++ 模拟 | 更新日期: 2023-09-27 18:05:48

是否有办法在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。

的场景:我正在努力通过利用c#中Random()的使用来"破解"几个加密恶意软件来生成密钥。显然，这是弱的，只有2^32个可能的密钥，约4.3B个密钥，这是在猜测的可能性范围内。我曾经用c#写过brute - forcers，但是无论我如何优化，它们都相当慢。我想在c++中实现一个brute - forcer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，将来甚至可以利用GPU)，并以指数方式获得更好的输出。

显然，Random(seed) != srand(seed)，基于不同的生成器。有没有一种方法可以在c++中实现c#使用的PRNG ?我显然不能修改c#恶意软件，因为加密已经对受害者的文件进行了加密，所以我不能只是"重写两者以使用相同的通用RNG"。

在c++中模拟c# Random()(相同的数字)

你可以在这里看到Random (c#)的源代码

感谢大家的回答和评论。我在这里发布了我移植的c++代码，如果有人需要它用于类似的项目。这是复制/粘贴，只需要"翻译"几行，并将其分解成合适的原型。确认并排产生与c#应用程序完全相同的数字序列。:)

Random.h 

#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();
};

Random.cpp 

#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();
}

Main.cpp 

#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;
}
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