#include int modExp(int base, int exponent, int modulus) {

951_20- guruh Atabayev Hojiakbar


13-amaliy mashg’ulot
Mavzu: Gomomorfik shifr algoritmlari bilan ishlash . Ochiq kalitli kriptotizimlar uchun gamomorflik xususiyatlarini dasturiy tomondan tekshirish.


#include
#include
int modExp(int base, int exponent, int modulus) {
if (exponent == 0)
return 1;
long long result = 1;
long long value = base;
while (exponent > 0) {
if (exponent % 2 == 1)
result = (result * value) % modulus;
value = (value * value) % modulus;
exponent /= 2;
}
return static_cast(result);
}
int homomorphicAddition(int ciphertext1, int ciphertext2, int publicKey, int modulus) {
int product = (ciphertext1 * ciphertext2) % modulus;
int result = modExp(product, publicKey, modulus);
return result;
}
int homomorphicMultiplication(int ciphertext, int scalar, int publicKey, int modulus) {
int exponentiatedScalar = modExp(scalar, publicKey, modulus);
int result = modExp(ciphertext, exponentiatedScalar, modulus);
return result;
}
int rsaEncrypt(int plaintext, int publicKey, int modulus) {
return modExp(plaintext, publicKey, modulus);
}
int rsaDecrypt(int ciphertext, int privateKey, int modulus) {
return modExp(ciphertext, privateKey, modulus);
}
int main() {
int p = 17; // Prime number
int q = 11; // Prime number
int n = p * q; // Modulus
int phi = (p - 1) * (q - 1); // Euler's totient function
int e = 7; // Public key
// while (e < phi) {
// if (isPrime(e) && std::gcd(e, phi) == 1)
// break;
// else
// ++e;
// }
int d = 1; // Private key
while ((d * e) % phi != 1) {
++d;
}
int plaintext = 42;
int ciphertext = rsaEncrypt(plaintext, e, n);
std::cout << "Ciphertext: " << ciphertext << std::endl;
int decrypted = rsaDecrypt(ciphertext, d, n);
std::cout << "Decrypted: " << decrypted << std::endl;
int plaintext1 = 10;
int plaintext2 = 7;
int publicKey = e;
int privateKey = d;
int ciphertext1 = modExp(plaintext1, publicKey, n);
int ciphertext2 = modExp(plaintext2, publicKey, n);
int additionResult = homomorphicAddition(ciphertext1, ciphertext2, publicKey, n);
int scalar = 5;
int multiplicationResult = homomorphicMultiplication(ciphertext1, scalar, publicKey, n);
int decryptedAdditionResult = modExp(additionResult, privateKey, n);
int decryptedMultiplicationResult = modExp(multiplicationResult, privateKey, n);
std::cout << "Homomorphic Addition Result: " << decryptedAdditionResult << std::endl;
std::cout << "Homomorphic Multiplication Result: " << decryptedMultiplicationResult << std::endl;
return 0;
}