Solver for mission 8 https://www.youtube.com/watch?v=7RotbY17tKk

mission8.cpp

#include <cstdio>
#include <ctime>
#include <iostream>

using namespace std;

const __int32 start_time = 1500465600; // guessed time
const __int32 end_time = 1500498000; // guessed time

__int8 encryptedMessage[] = 
{
    0x9a, 0x60, 0x76, 0x14, 0x8b, 0x36, 0x5a, 0x10, 0x2b, 0x91, 0xc4, 0x6c, 0xab, 0x27, 0x92, 0x99,
    0xf8, 0x6a, 0xec, 0x5d, 0x32, 0x20, 0x3d, 0x61, 0x8f, 0xc7, 0xfb, 0xdd, 0x02, 0x72, 0xbf,
};

static_assert(sizeof(encryptedMessage) == 31);

void testTime(__int64 time)
{
    srand(time);

    __int8 key[31] = { 0 };

    for (auto& byte : key)
    {
        auto v5 = rand();
        byte = v5 - ((unsigned __int64)(2139127681i64 * v5 >> 39) - (v5 >> 31));
    }

    __int8 outMsg[31] = { 0 };
    for (auto i = 0; i < 31; ++i)
        outMsg[i] = encryptedMessage[i] ^ key[i];

    bool ok = true;
    for (auto byte : outMsg)
    {
        if (byte < 32 || byte > 127)
        {
            ok = false;
            break;
        }
    }

    if (ok)
    {
        printf("%.*s\n", 31, outMsg);
        printf("%u\n", time);

        for (auto& byte : key)
        {
            union
            {
                unsigned __int32 i32;
                __int8 i8;
            } c;
            c.i32 = 0;
            c.i8 = byte;
            printf("%.2X ", c.i32);
        }
        printf("\n");
    }
}

int main()
{
    cout << "Starting" << endl;
    for (auto i = start_time; i <= end_time; ++i)
        testTime(i);

    cout << "Finished" << endl;
    cin.get();
    return 0;
}