PirQuery PIRClient::generate_query()

in pir_client.cpp [25:62]

• 31 lines of code
• 5 McCabe index (conditional complexity)

PirQuery PIRClient::generate_query(uint64_t desiredIndex) {

    indices_ = compute_indices(desiredIndex, pir_params_.nvec);

    compute_inverse_scales(); 

    vector<vector<Ciphertext> > result(pir_params_.d);
    int N = params_.poly_modulus_degree(); 

    Plaintext pt(params_.poly_modulus_degree());
    for (uint32_t i = 0; i < indices_.size(); i++) {
        uint32_t num_ptxts = ceil( (pir_params_.nvec[i] + 0.0) / N);
        // initialize result. 
        cout << "Client: index " << i + 1  <<  "/ " <<  indices_.size() << " = " << indices_[i] << endl; 
        cout << "Client: number of ctxts needed for query = " << num_ptxts << endl;
        for (uint32_t j =0; j < num_ptxts; j++){
            pt.set_zero();
            if (indices_[i] > N*(j+1) || indices_[i] < N*j){
#ifdef DEBUG
                cout << "Client: coming here: so just encrypt zero." << endl; 
#endif 
                // just encrypt zero
            } else{
#ifdef DEBUG
                cout << "Client: encrypting a real thing " << endl; 
#endif 
                uint64_t real_index = indices_[i] - N*j; 
                pt[real_index] = 1;
            }
            Ciphertext dest;
            encryptor_->encrypt(pt, dest);
            dest.parms_id() = params_.parms_id();
            result[i].push_back(dest);
        }   
    }

    return result;
}