simple-integers-serial-bgvrns.cpp

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/*
  Simple example for BGVrns (integer arithmetic) with serialization. Refer to
  simple-real-numbers-serial file for an example of how to use this in a "client-server" setup
 */

#include "openfhe.h"

// header files needed for serialization
#include "ciphertext-ser.h"
#include "cryptocontext-ser.h"
#include "key/key-ser.h"
#include "scheme/bgvrns/bgvrns-ser.h"

using namespace lbcrypto;

const std::string DATAFOLDER = "demoData";

int main() {
    std::cout << "This program requres the subdirectory `" << DATAFOLDER << "' to exist, otherwise you will get "
              << "an error writing serializations." << std::endl;

    // Sample Program: Step 1 - Set CryptoContext
    CCParams<CryptoContextBGVRNS> parameters;
    parameters.SetMultiplicativeDepth(2);
    parameters.SetPlaintextModulus(65537);

    CryptoContext<DCRTPoly> cryptoContext = GenCryptoContext(parameters);
    // Enable features that you wish to use
    cryptoContext->Enable(PKE);
    cryptoContext->Enable(KEYSWITCH);
    cryptoContext->Enable(LEVELEDSHE);

    std::cout << "\nThe cryptocontext has been generated." << std::endl;

    // Serialize cryptocontext
    if (!Serial::SerializeToFile(DATAFOLDER + "/cryptocontext.txt", cryptoContext, SerType::BINARY)) {
        std::cerr << "Error writing serialization of the crypto context to "
                     "cryptocontext.txt"
                  << std::endl;
        return 1;
    }
    std::cout << "The cryptocontext has been serialized." << std::endl;

    // Sample Program: Step 2 - Key Generation

    // Initialize Public Key Containers
    KeyPair<DCRTPoly> keyPair;

    // Generate a public/private key pair
    keyPair = cryptoContext->KeyGen();

    std::cout << "The key pair has been generated." << std::endl;

    // Serialize the public key
    if (!Serial::SerializeToFile(DATAFOLDER + "/key-public.txt", keyPair.publicKey, SerType::BINARY)) {
        std::cerr << "Error writing serialization of public key to key-public.txt" << std::endl;
        return 1;
    }
    std::cout << "The public key has been serialized." << std::endl;

    // Serialize the secret key
    if (!Serial::SerializeToFile(DATAFOLDER + "/key-private.txt", keyPair.secretKey, SerType::BINARY)) {
        std::cerr << "Error writing serialization of private key to key-private.txt" << std::endl;
        return 1;
    }
    std::cout << "The secret key has been serialized." << std::endl;

    // Generate the relinearization key
    cryptoContext->EvalMultKeyGen(keyPair.secretKey);

    std::cout << "The eval mult keys have been generated." << std::endl;

    // Serialize the relinearization (evaluation) key for homomorphic
    // multiplication
    std::ofstream emkeyfile(DATAFOLDER + "/" + "key-eval-mult.txt", std::ios::out | std::ios::binary);
    if (emkeyfile.is_open()) {
        if (cryptoContext->SerializeEvalMultKey(emkeyfile, SerType::BINARY) == false) {
            std::cerr << "Error writing serialization of the eval mult keys to "
                         "key-eval-mult.txt"
                      << std::endl;
            return 1;
        }
        std::cout << "The eval mult keys have been serialized." << std::endl;

        emkeyfile.close();
    }
    else {
        std::cerr << "Error serializing eval mult keys" << std::endl;
        return 1;
    }

    // Generate the rotation evaluation keys
    cryptoContext->EvalRotateKeyGen(keyPair.secretKey, {1, 2, -1, -2});

    std::cout << "The rotation keys have been generated." << std::endl;

    // Serialize the rotation keyhs
    std::ofstream erkeyfile(DATAFOLDER + "/" + "key-eval-rot.txt", std::ios::out | std::ios::binary);
    if (erkeyfile.is_open()) {
        if (cryptoContext->SerializeEvalAutomorphismKey(erkeyfile, SerType::BINARY) == false) {
            std::cerr << "Error writing serialization of the eval rotation keys to "
                         "key-eval-rot.txt"
                      << std::endl;
            return 1;
        }
        std::cout << "The eval rotation keys have been serialized." << std::endl;

        erkeyfile.close();
    }
    else {
        std::cerr << "Error serializing eval rotation keys" << std::endl;
        return 1;
    }

    // Sample Program: Step 3: Encryption

    // First plaintext vector is encoded
    std::vector<int64_t> vectorOfInts1 = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
    Plaintext plaintext1               = cryptoContext->MakePackedPlaintext(vectorOfInts1);
    // Second plaintext vector is encoded
    std::vector<int64_t> vectorOfInts2 = {3, 2, 1, 4, 5, 6, 7, 8, 9, 10, 11, 12};
    Plaintext plaintext2               = cryptoContext->MakePackedPlaintext(vectorOfInts2);
    // Third plaintext vector is encoded
    std::vector<int64_t> vectorOfInts3 = {1, 2, 5, 2, 5, 6, 7, 8, 9, 10, 11, 12};
    Plaintext plaintext3               = cryptoContext->MakePackedPlaintext(vectorOfInts3);

    std::cout << "Plaintext #1: " << plaintext1 << std::endl;
    std::cout << "Plaintext #2: " << plaintext2 << std::endl;
    std::cout << "Plaintext #3: " << plaintext3 << std::endl;

    // The encoded vectors are encrypted
    auto ciphertext1 = cryptoContext->Encrypt(keyPair.publicKey, plaintext1);
    auto ciphertext2 = cryptoContext->Encrypt(keyPair.publicKey, plaintext2);
    auto ciphertext3 = cryptoContext->Encrypt(keyPair.publicKey, plaintext3);

    std::cout << "The plaintexts have been encrypted." << std::endl;

    if (!Serial::SerializeToFile(DATAFOLDER + "/" + "ciphertext1.txt", ciphertext1, SerType::BINARY)) {
        std::cerr << "Error writing serialization of ciphertext 1 to ciphertext1.txt" << std::endl;
        return 1;
    }
    std::cout << "The first ciphertext has been serialized." << std::endl;

    if (!Serial::SerializeToFile(DATAFOLDER + "/" + "ciphertext2.txt", ciphertext2, SerType::BINARY)) {
        std::cerr << "Error writing serialization of ciphertext 2 to ciphertext2.txt" << std::endl;
        return 1;
    }
    std::cout << "The second ciphertext has been serialized." << std::endl;

    if (!Serial::SerializeToFile(DATAFOLDER + "/" + "ciphertext3.txt", ciphertext3, SerType::BINARY)) {
        std::cerr << "Error writing serialization of ciphertext 3 to ciphertext3.txt" << std::endl;
        return 1;
    }
    std::cout << "The third ciphertext has been serialized." << std::endl;

    // Sample Program: Step 4 - Evaluation

    // OpenFHE maintains an internal map of CryptoContext objects which are
    // indexed by a tag and the tag is applied to both the CryptoContext and some
    // of the keys. When deserializing a context, OpenFHE checks for the tag and
    // if it finds it in the CryptoContext map, it will return the stored version.
    // Hence, we need to clear the context and clear the keys.
    cryptoContext->ClearEvalMultKeys();
    cryptoContext->ClearEvalAutomorphismKeys();
    lbcrypto::CryptoContextFactory<lbcrypto::DCRTPoly>::ReleaseAllContexts();

    // Deserialize the crypto context
    CryptoContext<DCRTPoly> cc;
    if (!Serial::DeserializeFromFile(DATAFOLDER + "/cryptocontext.txt", cc, SerType::BINARY)) {
        std::cerr << "I cannot read serialization from " << DATAFOLDER + "/cryptocontext.txt" << std::endl;
        return 1;
    }
    std::cout << "The cryptocontext has been deserialized." << std::endl;

    PublicKey<DCRTPoly> pk;
    if (Serial::DeserializeFromFile(DATAFOLDER + "/key-public.txt", pk, SerType::BINARY) == false) {
        std::cerr << "Could not read public key" << std::endl;
        return 1;
    }
    std::cout << "The public key has been deserialized." << std::endl;

    std::ifstream emkeys(DATAFOLDER + "/key-eval-mult.txt", std::ios::in | std::ios::binary);
    if (!emkeys.is_open()) {
        std::cerr << "I cannot read serialization from " << DATAFOLDER + "/key-eval-mult.txt" << std::endl;
        return 1;
    }
    if (cc->DeserializeEvalMultKey(emkeys, SerType::BINARY) == false) {
        std::cerr << "Could not deserialize the eval mult key file" << std::endl;
        return 1;
    }
    std::cout << "Deserialized the eval mult keys." << std::endl;

    std::ifstream erkeys(DATAFOLDER + "/key-eval-rot.txt", std::ios::in | std::ios::binary);
    if (!erkeys.is_open()) {
        std::cerr << "I cannot read serialization from " << DATAFOLDER + "/key-eval-rot.txt" << std::endl;
        return 1;
    }
    if (cc->DeserializeEvalAutomorphismKey(erkeys, SerType::BINARY) == false) {
        std::cerr << "Could not deserialize the eval rotation key file" << std::endl;
        return 1;
    }
    std::cout << "Deserialized the eval rotation keys." << std::endl;

    // deserializing ciphertexts
    Ciphertext<DCRTPoly> ct1;
    if (Serial::DeserializeFromFile(DATAFOLDER + "/ciphertext1.txt", ct1, SerType::BINARY) == false) {
        std::cerr << "Could not read the ciphertext" << std::endl;
        return 1;
    }
    std::cout << "The first ciphertext has been deserialized." << std::endl;

    Ciphertext<DCRTPoly> ct2;
    if (Serial::DeserializeFromFile(DATAFOLDER + "/ciphertext2.txt", ct2, SerType::BINARY) == false) {
        std::cerr << "Could not read the ciphertext" << std::endl;
        return 1;
    }
    std::cout << "The second ciphertext has been deserialized." << std::endl;

    Ciphertext<DCRTPoly> ct3;
    if (Serial::DeserializeFromFile(DATAFOLDER + "/ciphertext3.txt", ct3, SerType::BINARY) == false) {
        std::cerr << "Could not read the ciphertext" << std::endl;
        return 1;
    }
    std::cout << "The third ciphertext has been deserialized." << std::endl;

    // Homomorphic additions
    auto ciphertextAdd12     = cc->EvalAdd(ct1, ct2);              // iphertext2);
    auto ciphertextAddResult = cc->EvalAdd(ciphertextAdd12, ct3);  // iphertext3);

    // Homomorphic multiplications
    auto ciphertextMul12      = cc->EvalMult(ct1, ct2);              // iphertext2);
    auto ciphertextMultResult = cc->EvalMult(ciphertextMul12, ct3);  // iphertext3);

    // Homomorphic rotations
    auto ciphertextRot1 = cc->EvalRotate(ct1, 1);
    auto ciphertextRot2 = cc->EvalRotate(ct1, 2);
    auto ciphertextRot3 = cc->EvalRotate(ct1, -1);
    auto ciphertextRot4 = cc->EvalRotate(ct1, -2);

    // Sample Program: Step 5 - Decryption

    PrivateKey<DCRTPoly> sk;
    if (Serial::DeserializeFromFile(DATAFOLDER + "/key-private.txt", sk, SerType::BINARY) == false) {
        std::cerr << "Could not read secret key" << std::endl;
        return 1;
    }
    std::cout << "The secret key has been deserialized." << std::endl;

    // Decrypt the result of additions
    Plaintext plaintextAddResult;
    cc->Decrypt(sk, ciphertextAddResult, &plaintextAddResult);

    // Decrypt the result of multiplications
    Plaintext plaintextMultResult;
    cc->Decrypt(sk, ciphertextMultResult, &plaintextMultResult);

    // Decrypt the result of rotations
    Plaintext plaintextRot1;
    cc->Decrypt(sk, ciphertextRot1, &plaintextRot1);
    Plaintext plaintextRot2;
    cc->Decrypt(sk, ciphertextRot2, &plaintextRot2);
    Plaintext plaintextRot3;
    cc->Decrypt(sk, ciphertextRot3, &plaintextRot3);
    Plaintext plaintextRot4;
    cc->Decrypt(sk, ciphertextRot4, &plaintextRot4);

    // Shows only the same number of elements as in the original plaintext vector
    // By default it will show all coefficients in the BFV-encoded polynomial
    plaintextRot1->SetLength(vectorOfInts1.size());
    plaintextRot2->SetLength(vectorOfInts1.size());
    plaintextRot3->SetLength(vectorOfInts1.size());
    plaintextRot4->SetLength(vectorOfInts1.size());

    // Output results
    std::cout << "\nResults of homomorphic computations" << std::endl;
    std::cout << "#1 + #2 + #3: " << plaintextAddResult << std::endl;
    std::cout << "#1 * #2 * #3: " << plaintextMultResult << std::endl;
    std::cout << "Left rotation of #1 by 1: " << plaintextRot1 << std::endl;
    std::cout << "Left rotation of #1 by 2: " << plaintextRot2 << std::endl;
    std::cout << "Right rotation of #1 by 1: " << plaintextRot3 << std::endl;
    std::cout << "Right rotation of #1 by 2: " << plaintextRot4 << std::endl;

    return 0;
}