des-cipher/main.cpp at master · n3oxmind/des-cipher · GitHub

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#include "des.h"

#include <cstring>
#include <iostream>
#include <string>

namespace {

void print_usage(const char* program) {
    std::cerr
        << "Usage: " << program << " <-e|-d> -k <key> -t <text> [-v]\n"
        << "\n"
        << "Options:\n"
        << "  -e          Encrypt mode\n"
        << "  -d          Decrypt mode\n"
        << "  -k <key>    16-character hex key (64 bits)\n"
        << "  -t <text>   16-character hex input (64 bits)\n"
        << "  -v          Verbose: show all 16 rounds\n"
        << "  -h          Show this help\n"
        << "\n"
        << "Examples:\n"
        << "  " << program << " -e -k AABB09182736CCDD -t 123456ABCD132536\n"
        << "  " << program << " -d -k AABB09182736CCDD -t C0B7A8D05F3A829C\n"
        << "  " << program << " -e -k AABB09182736CCDD -t 123456ABCD132536 -v\n";
}

bool is_valid_hex(const std::string& s, std::size_t expected_len) {
    if (s.size() != expected_len) return false;
    for (char c : s) {
        if (!((c >= '0' && c <= '9') ||
              (c >= 'A' && c <= 'F') ||
              (c >= 'a' && c <= 'f'))) {
            return false;
        }
    }
    return true;
}

std::string to_upper(std::string s) {
    for (char& c : s) {
        if (c >= 'a' && c <= 'f') c -= 32;
    }
    return s;
}

} // namespace

int main(int argc, char* argv[]) {
    enum class Mode { none, encrypt, decrypt };
    Mode mode = Mode::none;
    std::string key;
    std::string text;
    bool verbose = false;

    for (int i = 1; i < argc; ++i) {
        if (std::strcmp(argv[i], "-e") == 0) {
            mode = Mode::encrypt;
        } else if (std::strcmp(argv[i], "-d") == 0) {
            mode = Mode::decrypt;
        } else if (std::strcmp(argv[i], "-k") == 0 && i + 1 < argc) {
            key = argv[++i];
        } else if (std::strcmp(argv[i], "-t") == 0 && i + 1 < argc) {
            text = argv[++i];
        } else if (std::strcmp(argv[i], "-v") == 0) {
            verbose = true;
        } else if (std::strcmp(argv[i], "-h") == 0 ||
                   std::strcmp(argv[i], "--help") == 0) {
            print_usage(argv[0]);
            return 0;
        } else {
            std::cerr << "Unknown option: " << argv[i] << '\n';
            print_usage(argv[0]);
            return 1;
        }
    }

    if (mode == Mode::none || key.empty() || text.empty()) {
        print_usage(argv[0]);
        return 1;
    }

    key  = to_upper(key);
    text = to_upper(text);

    if (!is_valid_hex(key, 16)) {
        std::cerr << "Error: Key must be exactly 16 hex characters.\n";
        return 1;
    }
    if (!is_valid_hex(text, 16)) {
        std::cerr << "Error: Input text must be exactly 16 hex characters.\n";
        return 1;
    }

    try {
        des::Cipher cipher(key);
        std::string result;

        if (mode == Mode::encrypt) {
            result = cipher.encrypt(text, verbose);
            std::cout << "Plaintext : " << des::color::white << text
                      << des::color::reset << '\n';
            std::cout << "Key       : " << des::color::white << key
                      << des::color::reset << '\n';
            std::cout << "Ciphertext: " << des::color::bold_red << result
                      << des::color::reset << '\n';
        } else {
            result = cipher.decrypt(text, verbose);
            std::cout << "Ciphertext: " << des::color::white << text
                      << des::color::reset << '\n';
            std::cout << "Key       : " << des::color::white << key
                      << des::color::reset << '\n';
            std::cout << "Plaintext : " << des::color::bold_green << result
                      << des::color::reset << '\n';
        }
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << '\n';
        return 1;
    }

    return 0;
}