simple-integers-bgvrns.cpp

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/*
  Simple example for BGVrns (integer arithmetic)
 */

#include "openfhe.h"

using namespace lbcrypto;

int main() {
    // 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);

    // Sample Program: Step 2 - Key Generation

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

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

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

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

    // 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);

    // 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);

    // Sample Program: Step 4 - Evaluation

    // Homomorphic additions
    auto ciphertextAdd12     = cryptoContext->EvalAdd(ciphertext1, ciphertext2);
    auto ciphertextAddResult = cryptoContext->EvalAdd(ciphertextAdd12, ciphertext3);

    // Homomorphic multiplications
    // modulus switching is done automatically because by default the modulus
    // switching method is set to AUTO (rather than MANUAL)
    auto ciphertextMul12      = cryptoContext->EvalMult(ciphertext1, ciphertext2);
    auto ciphertextMultResult = cryptoContext->EvalMult(ciphertextMul12, ciphertext3);
    // Homomorphic rotations
    auto ciphertextRot1 = cryptoContext->EvalRotate(ciphertext1, 1);
    auto ciphertextRot2 = cryptoContext->EvalRotate(ciphertext1, 2);
    auto ciphertextRot3 = cryptoContext->EvalRotate(ciphertext1, -1);
    auto ciphertextRot4 = cryptoContext->EvalRotate(ciphertext1, -2);

    // Sample Program: Step 5 - Decryption

    // Decrypt the result of additions
    Plaintext plaintextAddResult;
    cryptoContext->Decrypt(keyPair.secretKey, ciphertextAddResult, &plaintextAddResult);

    // Decrypt the result of multiplications
    Plaintext plaintextMultResult;
    cryptoContext->Decrypt(keyPair.secretKey, ciphertextMultResult, &plaintextMultResult);

    // Decrypt the result of rotations
    Plaintext plaintextRot1;
    cryptoContext->Decrypt(keyPair.secretKey, ciphertextRot1, &plaintextRot1);
    Plaintext plaintextRot2;
    cryptoContext->Decrypt(keyPair.secretKey, ciphertextRot2, &plaintextRot2);
    Plaintext plaintextRot3;
    cryptoContext->Decrypt(keyPair.secretKey, ciphertextRot3, &plaintextRot3);
    Plaintext plaintextRot4;
    cryptoContext->Decrypt(keyPair.secretKey, ciphertextRot4, &plaintextRot4);

    plaintextRot1->SetLength(vectorOfInts1.size());
    plaintextRot2->SetLength(vectorOfInts1.size());
    plaintextRot3->SetLength(vectorOfInts1.size());
    plaintextRot4->SetLength(vectorOfInts1.size());

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

    // 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;
}