inline void PIRServer::multiply_power_of_X()

in pir_server.cpp [350:373]

• 15 lines of code
• 3 McCabe index (conditional complexity)

inline void PIRServer::multiply_power_of_X(const Ciphertext &encrypted, Ciphertext &destination,
                                    uint32_t index) {

    auto coeff_mod_count = params_.coeff_modulus().size();
    auto coeff_count = params_.poly_modulus_degree();
    auto encrypted_count = encrypted.size();

    //cout << "coeff mod count for power of X = " << coeff_mod_count << endl; 
    //cout << "coeff count for power of X = " << coeff_count << endl; 

    // First copy over.
    destination = encrypted;

    // Prepare for destination
    // Multiply X^index for each ciphertext polynomial
    for (int i = 0; i < encrypted_count; i++) {
        for (int j = 0; j < coeff_mod_count; j++) {
            negacyclic_shift_poly_coeffmod(encrypted.data(i) + (j * coeff_count),
                                           coeff_count, index,
                                           params_.coeff_modulus()[j],
                                           destination.data(i) + (j * coeff_count));
        }
    }
}