Question

How to XOR byte vectors in C++

Answer 1

#include <iostream>
#include <cstdint>
#include <vector>
#include <bitset>

int main() {
    std::vector<uint8_t> a{'A', 'e', 'r', 'y', 'n'};
    std::vector<uint8_t> b{'A', 'l', 'b', 'u', 's'};

    std::vector<uint8_t> c(a.size());
    for (size_t i = 0; i < a.size(); ++i) {
        c[i] = a[i] ^ b[i];
    }

    std::cout << "a: ";
    for (auto ch : a)
        std::cout << std::bitset<8>(ch) << ' ';
    std::cout << "\nb: ";
    for (auto ch : b)
        std::cout << std::bitset<8>(ch) << ' ';
    std::cout << "\nc: ";
    for (auto ch : c)
        std::cout << std::bitset<8>(ch) << ' ';
    std::cout << "\nc: ";
    for (auto ch : c)
        std::cout << static_cast<int>(ch) << ' ';
}



/*
run:

a: 01000001 01100101 01110010 01111001 01101110 
b: 01000001 01101100 01100010 01110101 01110011 
c: 00000000 00001001 00010000 00001100 00011101 
c: 0 9 16 12 29 

*/

 

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Answer 2

#include <iostream>
#include <cstdint>
#include <vector>
#include <bitset>

// XOR two byte arrays of the same length
std::vector<uint8_t> xorBytes(const std::vector<uint8_t>& a, const std::vector<uint8_t>& b) {
    std::vector<uint8_t> result(a.size());
    for (size_t i = 0; i < a.size(); ++i) {
        result[i] = a[i] ^ b[i];
    }
    return result;
}

// Print byte array as bitset
void printBitsetArray(const std::string& label, const std::vector<uint8_t>& array) {
    std::cout << label << ": ";
    for (auto ch : array)
        std::cout << std::bitset<8>(ch) << ' ';
    std::cout << '\n';
}

int main() {
    std::vector<uint8_t> a{'A', 'e', 'r', 'y', 'n'};
    std::vector<uint8_t> b{'A', 'l', 'b', 'u', 's'};

    std::vector<uint8_t> c = xorBytes(a, b);

    printBitsetArray("a", a);
    printBitsetArray("b", b);
    printBitsetArray("c", c);

    std::cout << "c: ";
    for (auto ch : c)
        std::cout << static_cast<int>(ch) << ' ';
}



/*
run:

a: 01000001 01100101 01110010 01111001 01101110 
b: 01000001 01101100 01100010 01110101 01110011 
c: 00000000 00001001 00010000 00001100 00011101 
c: 0 9 16 12 29 

*/

 

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