Reverse Checksum

Solve the riddle...

#include <iostream>
#include <string>
#include <stdint.h>

uint64_t checksum(std::string& s) {
    uint64_t result = 0;
    for (auto c : s) {
        result <<= 7;
        result ^= c;
    }
    return result;
}

int main() {
    std::string msg = "The answer to this question is: ";
    std::cout << checksum(msg) << std::endl;
    // Expected Output: 3559195706944969009
    return 0;
}

Note: auto is a new feature since C++11.