private static void HomoExample()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.BFV);
parms.PolyModulusDegree = 2048;
parms.CoeffModulus = DefaultParams.CoeffModulus128(polyModulusDegree: 2048);
parms.PlainModulus = new SmallModulus(1 << 8);
SEALContext context = SEALContext.Create(parms);
IntegerEncoder encoder = new IntegerEncoder(context);
KeyGenerator keygen = new KeyGenerator(context);
Microsoft.Research.SEAL.PublicKey publicKey = keygen.PublicKey;
SecretKey secretKey = keygen.SecretKey;
Encryptor encryptor = new Encryptor(context, publicKey);
Evaluator evaluator = new Evaluator(context);
Decryptor decryptor = new Decryptor(context, secretKey);
int value1 = 5;
Plaintext plain1 = encoder.Encode(value1);
Console.WriteLine($"Encoded {value1} as polynomial {plain1.ToString()} (plain1)");
int value2 = -7;
Plaintext plain2 = encoder.Encode(value2);
Console.WriteLine($"Encoded {value2} as polynomial {plain2.ToString()} (plain2)");
Ciphertext encrypted1 = new Ciphertext();
Ciphertext encrypted2 = new Ciphertext();
Console.Write("Encrypting plain1: ");
encryptor.Encrypt(plain1, encrypted1);
Console.WriteLine("Done (encrypted1)");
Plaintext plainResult = new Plaintext();
decryptor.Decrypt(encrypted1, plainResult);
Console.WriteLine(encoder.DecodeInt32(plainResult));
Console.Write("Encrypting plain2: ");
encryptor.Encrypt(plain2, encrypted2);
Console.WriteLine("Done (encrypted2)");
Console.WriteLine($"Noise budget in encrypted1: {decryptor.InvariantNoiseBudget(encrypted1)} bits");
Console.WriteLine($"Noise budget in encrypted2: {decryptor.InvariantNoiseBudget(encrypted2)} bits");
evaluator.NegateInplace(encrypted1);
Console.WriteLine($"Noise budget in -encrypted1: {decryptor.InvariantNoiseBudget(encrypted1)} bits");
evaluator.AddInplace(encrypted1, encrypted2);
Console.WriteLine($"Noise budget in -encrypted1 + encrypted2: {decryptor.InvariantNoiseBudget(encrypted1)} bits");
evaluator.MultiplyInplace(encrypted1, encrypted2);
Console.WriteLine($"Noise budget in (-encrypted1 + encrypted2) * encrypted2: {decryptor.InvariantNoiseBudget(encrypted1)} bits");
plainResult = new Plaintext();
Console.Write("Decrypting result: ");
decryptor.Decrypt(encrypted1, plainResult);
Console.WriteLine("Done");
Console.WriteLine($"Plaintext polynomial: {plainResult.ToString()}");
Console.WriteLine($"Decoded integer: {encoder.DecodeInt32(plainResult)}");
}
