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#include <openssl/des.h>
#include <openssl/evp.h>
#include <cstdlib>
#include <iomanip>
#include <iostream>
void PrintCblock(const DES_cblock &b, bool end_line = true) {
std::cout << std::hex << std::right << std::setfill('0');
for (auto c : b) {
std::cout << std::setw(2) << static_cast<int>(c);
}
if (end_line) {
std::cout << std::endl;
}
}
int main() {
auto cipher = EVP_des_cfb();
std::cout << "Selected cipher: des_cfb" << std::endl;
auto key_length = EVP_CIPHER_key_length(cipher);
std::cout << "Key length: " << key_length << std::endl;
auto iv_length = EVP_CIPHER_iv_length(cipher);
std::cout << "IV length: " << iv_length << std::endl;
auto block_length = EVP_CIPHER_block_size(cipher);
std::cout << "Block length: " << block_length << std::endl;
DES_cblock key;
std::srand(std::time(nullptr));
std::cout << std::hex << std::setfill('0');
if (DES_random_key(&key) == 0) {
std::cerr << "Failed to generate key." << std::endl;
return 1;
} else {
std::cout << "Succeeded to generate key." << std::endl;
std::cout << "Key: ";
PrintCblock(key);
}
DES_key_schedule key_schedule;
{
auto result = DES_set_key_checked(&key, &key_schedule);
if (result == -1) {
std::cerr << "Parity is wrong." << std::endl;
return 1;
} else if (result == -2) {
std::cerr << "Key is too weak." << std::endl;
}
}
DES_cblock clear_text = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
std::cout << "Clear text: " << std::hex;
PrintCblock(clear_text);
DES_cblock cipher_text;
DES_ecb_encrypt(&clear_text, &cipher_text, &key_schedule, 1);
std::cout << "Cipher text after encrypted: " << std::hex;
PrintCblock(cipher_text);
DES_ecb_encrypt(&cipher_text, &clear_text, &key_schedule, 0);
std::cout << "Clear text after decrypted: " << std::hex;
PrintCblock(clear_text);
return 0;
}
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