public void ScaleTest()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS)
{
PolyModulusDegree = 8,
CoeffModulus = CoeffModulus.Create(8, new int[] { 40, 40, 40, 40 })
};
SEALContext context = new SEALContext(parms,
expandModChain: true,
secLevel: SecLevelType.None);
KeyGenerator keygen = new KeyGenerator(context);
keygen.CreatePublicKey(out PublicKey publicKey);
keygen.CreateGaloisKeys(out GaloisKeys galoisKeys);
Encryptor encryptor = new Encryptor(context, publicKey);
Evaluator evaluator = new Evaluator(context);
CKKSEncoder encoder = new CKKSEncoder(context);
MemoryPoolHandle pool = MemoryManager.GetPool(MMProfOpt.ForceNew);
Assert.AreEqual(0ul, pool.AllocByteCount);
Ciphertext encrypted = new Ciphertext(pool);
Plaintext plain = new Plaintext();
MemoryPoolHandle cipherPool = encrypted.Pool;
Assert.IsNotNull(cipherPool);
Assert.AreEqual(0ul, cipherPool.AllocByteCount);
List <Complex> input = new List <Complex>()
{
new Complex(1, 1),
new Complex(2, 2),
new Complex(3, 3),
new Complex(4, 4)
};
double delta = Math.Pow(2, 70);
encoder.Encode(input, context.FirstParmsId, delta, plain);
encryptor.Encrypt(plain, encrypted);
Assert.AreEqual(delta, encrypted.Scale, delta: Math.Pow(2, 60));
Ciphertext encrypted2 = new Ciphertext();
encrypted2.Set(encrypted);
Assert.AreEqual(delta, encrypted2.Scale, delta: Math.Pow(2, 60));
evaluator.RescaleToNextInplace(encrypted);
Assert.AreEqual(Math.Pow(2, 30), encrypted.Scale, delta: 10000);
Assert.AreNotEqual(0ul, cipherPool.AllocByteCount);
double newScale = Math.Pow(2, 10);
encrypted.Scale = newScale;
Assert.AreEqual(newScale, encrypted.Scale, delta: 100);
}
public void EncodeDecodeComplexTest()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS)
{
PolyModulusDegree = 64,
CoeffModulus = new List <SmallModulus>()
{
DefaultParams.SmallMods40Bit(0),
DefaultParams.SmallMods40Bit(1),
DefaultParams.SmallMods40Bit(2),
DefaultParams.SmallMods40Bit(3)
}
};
SEALContext context = SEALContext.Create(parms);
CKKSEncoder encoder = new CKKSEncoder(context);
Plaintext plain = new Plaintext();
Complex value = new Complex(3.1415, 2.71828);
encoder.Encode(value, scale: Math.Pow(2, 20), destination: plain);
List <Complex> result = new List <Complex>();
encoder.Decode(plain, result);
Assert.IsTrue(result.Count > 0);
Assert.AreEqual(3.1415, result[0].Real, delta: 0.0001);
Assert.AreEqual(2.71828, result[0].Imaginary, delta: 0.0001);
}
public void EncodeDecodeComplexTest()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS)
{
PolyModulusDegree = 64,
CoeffModulus = CoeffModulus.Create(64, new int[] { 40, 40, 40, 40 })
};
SEALContext context = new SEALContext(parms,
expandModChain: false,
secLevel: SecLevelType.None);
CKKSEncoder encoder = new CKKSEncoder(context);
Plaintext plain = new Plaintext();
Complex value = new Complex(3.1415, 2.71828);
encoder.Encode(value, scale: Math.Pow(2, 20), destination: plain);
List <Complex> result = new List <Complex>();
encoder.Decode(plain, result);
Assert.IsTrue(result.Count > 0);
Assert.AreEqual(3.1415, result[0].Real, delta: 0.0001);
Assert.AreEqual(2.71828, result[0].Imaginary, delta: 0.0001);
}
public void EncodeDecodeUlongTest()
{
int slots = 32;
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = (ulong)slots * 2;
parms.CoeffModulus = CoeffModulus.Create(64, new int[] { 40, 40, 40, 40 });
SEALContext context = new SEALContext(parms,
expandModChain: false,
secLevel: SecLevelType.None);
CKKSEncoder encoder = new CKKSEncoder(context);
Plaintext plain = new Plaintext();
List <Complex> result = new List <Complex>();
long value = 15;
encoder.Encode(value, plain);
encoder.Decode(plain, result);
for (int i = 0; i < slots; i++)
{
double tmp = Math.Abs(value - result[i].Real);
Assert.IsTrue(tmp < 0.5);
}
}
public void EncodeDecodeDoubleTest()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = 64;
parms.CoeffModulus = CoeffModulus.Create(64, new int[] { 40, 40, 40, 40 });
SEALContext context = new SEALContext(parms,
expandModChain: false,
secLevel: SecLevelType.None);
int slots = 16;
Plaintext plain = new Plaintext();
double delta = 1 << 16;
List <Complex> result = new List <Complex>();
CKKSEncoder encoder = new CKKSEncoder(context);
Assert.AreEqual(32ul, encoder.SlotCount);
double value = 10d;
encoder.Encode(value, delta, plain);
encoder.Decode(plain, result);
for (int i = 0; i < slots; i++)
{
double tmp = Math.Abs(value - result[i].Real);
Assert.IsTrue(tmp < 0.5);
}
}
public void EncodeDecodeVectorDoubleTest()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS)
{
PolyModulusDegree = 64,
CoeffModulus = CoeffModulus.Create(64, new int[] { 30, 30 })
};
SEALContext context = new SEALContext(parms,
expandModChain: false,
secLevel: SecLevelType.None);
CKKSEncoder encoder = new CKKSEncoder(context);
Plaintext plain = new Plaintext();
double[] values = new double[] { 0.1, 2.3, 34.4 };
encoder.Encode(values, scale: Math.Pow(2, 20), destination: plain);
List <double> result = new List <double>();
encoder.Decode(plain, result);
Assert.IsNotNull(result);
Assert.AreEqual(0.1, result[0], delta: 0.001);
Assert.AreEqual(2.3, result[1], delta: 0.001);
Assert.AreEqual(34.4, result[2], delta: 0.001);
}
public void EncodeDecodeUlongTest()
{
int slots = 32;
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = (ulong)slots * 2;
List <SmallModulus> coeffModulus = new List <SmallModulus>(4);
coeffModulus.Add(DefaultParams.SmallMods40Bit(0));
coeffModulus.Add(DefaultParams.SmallMods40Bit(1));
coeffModulus.Add(DefaultParams.SmallMods40Bit(2));
coeffModulus.Add(DefaultParams.SmallMods40Bit(3));
parms.CoeffModulus = coeffModulus;
SEALContext context = SEALContext.Create(parms);
CKKSEncoder encoder = new CKKSEncoder(context);
Plaintext plain = new Plaintext();
List <Complex> result = new List <Complex>();
long value = 15;
encoder.Encode(value, plain);
encoder.Decode(plain, result);
for (int i = 0; i < slots; i++)
{
double tmp = Math.Abs(value - result[i].Real);
Assert.IsTrue(tmp < 0.5);
}
}
//
private static void SinglePredict(Svc secureSvc, double[] feature, int i, CKKSEncoder encoder, Encryptor encryptor, Decryptor decryptor,
Stopwatch innerProductStopwatch, Stopwatch degreeStopwatch, Stopwatch negateStopwatch, Stopwatch serverDecisionStopWatch, double scale, Result[] results)
{
double finalResult = 0;
Console.WriteLine($"start {i} \n");
var plaintexts = new Plaintext();
var featuresCiphertexts = new Ciphertext();
encoder.Encode(feature, scale, plaintexts);
encryptor.Encrypt(plaintexts, featuresCiphertexts);
// Server side start
var cyphetResult = secureSvc.Predict(featuresCiphertexts, true, true, innerProductStopwatch, degreeStopwatch, negateStopwatch, serverDecisionStopWatch);
// Server side end
//timePredictSum.Stop();
Plaintext plainResult = new Plaintext();
decryptor.Decrypt(cyphetResult, plainResult);
List <double> result = new List <double>();
encoder.Decode(plainResult, result);
finalResult = result[0];
int estimation = finalResult > 0 ? 0 : 1;
Console.WriteLine($"\n ************************************************");
Console.WriteLine($"SVC estimation{i} is : {estimation} , result : {finalResult}");
//file.WriteLine($"{i} , {estimation} , {finalResult} ");
Console.WriteLine($"************************************************ \n");
results[i] = new Result(finalResult, estimation);
//Console.WriteLine($"SecureSVC estimation{i} is : {estimation} , finalResult = {finalResult} , Time = {timePredictSum.ElapsedMilliseconds}");
}
public static List <Ciphertext> Encrypt(
this byte[] data,
CKKSEncoder encoder,
Encryptor encryptor,
double scale,
int slots)
{
return(ComputeInBatches(
data,
slots,
bytes =>
{
using var pt = new Plaintext();
encoder.Encode(
bytes.Select(d => Convert.ToDouble(d)),
scale,
pt);
var ct = new Ciphertext();
encryptor.Encrypt(pt, ct);
return ct;
}));
}
public void EncodeDecodeVectorDoubleTest()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS)
{
PolyModulusDegree = 64,
CoeffModulus = new List <SmallModulus>()
{
DefaultParams.SmallMods30Bit(0),
DefaultParams.SmallMods30Bit(1)
}
};
SEALContext context = SEALContext.Create(parms);
CKKSEncoder encoder = new CKKSEncoder(context);
Plaintext plain = new Plaintext();
double[] values = new double[] { 0.1, 2.3, 34.4 };
encoder.Encode(values, scale: Math.Pow(2, 20), destination: plain);
List <double> result = new List <double>();
encoder.Decode(plain, result);
Assert.IsNotNull(result);
Assert.AreEqual(0.1, result[0], delta: 0.001);
Assert.AreEqual(2.3, result[1], delta: 0.001);
Assert.AreEqual(34.4, result[2], delta: 0.001);
}
public void EncodeDecodeDoubleTest()
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = 64;
List <SmallModulus> coeffModulus = new List <SmallModulus>(4);
coeffModulus.Add(DefaultParams.SmallMods40Bit(0));
coeffModulus.Add(DefaultParams.SmallMods40Bit(1));
coeffModulus.Add(DefaultParams.SmallMods40Bit(2));
coeffModulus.Add(DefaultParams.SmallMods40Bit(3));
parms.CoeffModulus = coeffModulus;
SEALContext context = SEALContext.Create(parms);
int slots = 16;
Plaintext plain = new Plaintext();
double delta = 1 << 16;
List <Complex> result = new List <Complex>();
CKKSEncoder encoder = new CKKSEncoder(context);
Assert.AreEqual(32ul, encoder.SlotCount);
double value = 10d;
encoder.Encode(value, delta, plain);
encoder.Decode(plain, result);
for (int i = 0; i < slots; i++)
{
double tmp = Math.Abs(value - result[i].Real);
Assert.IsTrue(tmp < 0.5);
}
}
public Bitmap DecryptFromVector(
Decryptor decryptor,
CKKSEncoder encoder)
{
var bmp = new Bitmap(_width, _height);
var rVals = _rValueVector.DecryptData(decryptor, encoder);
var gVals = _gValueVector.DecryptData(decryptor, encoder);
var bVals = _bValueVector.DecryptData(decryptor, encoder);
var data = new List <int>();
var ind = 0;
for (var i = 0; i < bmp.Width; i++)
{
for (var j = 0; j < bmp.Height; j++)
{
var color = Color.FromArgb(
_aValues[ind],
rVals[ind],
gVals[ind],
bVals[ind]);
data.Add(rVals[ind]);
bmp.SetPixel(i, j, color);
ind++;
}
}
return(bmp);
}
public CKKSDecryptor(SEALContext Context, SecretKey privateKey)
{
//Takes in a context and private key and creates instance of decoder and Context.
context = Context;
scale = Math.Pow(2.0, 40);
decryptor = new Decryptor(Context, privateKey);
encoder = new CKKSEncoder(Context);
}
public ImageProcessorServer(
Evaluator evaluator,
CKKSEncoder encoder,
double scale)
{
_evaluator = evaluator ?? throw new ArgumentNullException(nameof(evaluator));
encoder.Encode(0.3, scale, RMultiplePtx);
encoder.Encode(0.59, scale, GMultiplePtx);
encoder.Encode(0.11, scale, BMultiplePtx);
}
public static EncryptedImage FromBmp(
Bitmap bmp,
Encryptor encryptor,
CKKSEncoder encoder,
double scale,
int slots)
{
var count = bmp.Height * bmp.Width;
var aVals = new int[count];
var rVals = new Ciphertext[count];
var gVals = new Ciphertext[count];
var bVals = new Ciphertext[count];
var rValPlain = new byte[count];
var gValPlain = new byte[count];
var bValPlain = new byte[count];
var ind = 0;
for (var i = 0; i < bmp.Width; i++)
{
for (var j = 0; j < bmp.Height; j++)
{
var pixel = bmp.GetPixel(i, j);
aVals[ind] = pixel.A;
rValPlain[ind] = pixel.R;
gValPlain[ind] = pixel.G;
bValPlain[ind] = pixel.B;
// Add when implementing edge detector.
// rVals[ind] = pixel.R.Encrypt(encoder, encryptor, scale);
// gVals[ind] = pixel.G.Encrypt(encoder, encryptor, scale);
// bVals[ind] = pixel.B.Encrypt(encoder, encryptor, scale);
ind++;
}
}
return(new EncryptedImage(
bmp.Width,
bmp.Height,
aVals,
rVals,
gVals,
bVals,
rValPlain.Encrypt(encoder, encryptor, scale, slots),
gValPlain.Encrypt(encoder, encryptor, scale, slots),
bValPlain.Encrypt(encoder, encryptor, scale, slots)));
}
public SalaryComputation()
{
//Constructor.
parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = polyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create(
polyModulusDegree, new int[] { 60, 40, 40, 60 });
//parms.PlainModulus = PlainModulus.Batching(polyModulusDegree, 20);
context = new SEALContext(parms);
evaluator = new Evaluator(context);
encoder = new CKKSEncoder(context);
SetConstants();
}
//private static bool _firstTime = true;
//private static Decryptor _decryptor;
public SecureSvc(int nRows, double[][] vectors, double[][] coefficients, double[] intercepts,
String kernel, double gamma, double coef0, ulong degree , int power)
{
//this._nRows = nRows;
this._vectors = vectors;
this._coefficients = coefficients;
this._intercepts = intercepts;
this._kernel = Enum.Parse<Kernel>(kernel, true);
this._gamma = gamma;
this._coef0 = coef0;
this._degree = degree;
this._power = power;
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
ulong polyModulusDegree = 16384;
if (power >= 20 && power < 40 )
{
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree,
new int[] { 60, 20, 21, 22, 23, 24, 25, 26, 27, 60 });
}
else if (power >= 40 && power < 60)
{
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree,
new int[] { 60, 40, 40, 40, 40, 40, 40, 40 , 60 });
}
else if (power == 60)
{
polyModulusDegree = 32768;
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree,
new int[] { 60, 60, 60, 60, 60, 60, 60, 60, 60 });
}
parms.PolyModulusDegree = polyModulusDegree;
_context = new SEALContext(parms);
KeyGenerator keygen = new KeyGenerator(_context);
_publicKey = keygen.PublicKey;
_secretKey = keygen.SecretKey;
_relinKeys = keygen.RelinKeys();
_galoisKeys = keygen.GaloisKeys();
_encryptor = new Encryptor(_context, _publicKey);
_evaluator = new Evaluator(_context);
_decryptor = new Decryptor(_context, _secretKey);
_encoder = new CKKSEncoder(_context);
}
public BMIComputation(RelinKeys Keys)
{
parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = polyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create(
polyModulusDegree, new int[] { 60, 40, 40, 60 });
//parms.PlainModulus = PlainModulus.Batching(polyModulusDegree, 20);
context = new SEALContext(parms);
evaluator = new Evaluator(context);
encoder = new CKKSEncoder(context);
scale = Math.Pow(2.0, 40);
SetConstants();
KeysRelin = Keys;
}
public static Ciphertext Encrypt(
this byte data,
CKKSEncoder encoder,
Encryptor encryptor,
double scale)
{
using var pt = new Plaintext();
encoder.Encode(Convert.ToDouble(data), scale, pt);
var ct = new Ciphertext();
encryptor.Encrypt(pt, ct);
return(ct);
}
public CKKSEncryptor()
{
//Set scheme Primes and encryption parameters.
parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = polyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create(
polyModulusDegree, new int[] { 60, 40, 40, 60 });
scale = Math.Pow(2.0, 40);
context = new SEALContext(parms);
keygen = new KeyGenerator(context);
//Generate private and public key.
publicKey = keygen.PublicKey;
secretKey = keygen.SecretKey;
encryptor = new Encryptor(context, publicKey);
encoder = new CKKSEncoder(context);
KeysRelin = keygen.RelinKeys();
}
public static Plaintext[][][] GetWeightsPlaintext(CKKSEncoder encoder, double scale, double[][][] weights)
{
Plaintext[][][] toReturn = new Plaintext[weights.Length][][];
for (int i = 0; i < weights.Length; i++)
{
Plaintext[][] layerWeightsPlaintext = new Plaintext[weights[i].Length][];
for (int j = 0; j < weights[i].Length; j++)
{
Plaintext[] layerNodeWeightsPlaintext = new Plaintext[weights[i][j].Length];
for (int k = 0; k < weights[i][j].Length; k++)
{
Plaintext weightPT = new Plaintext();
encoder.Encode(weights[i][j][k], scale, weightPT);
layerNodeWeightsPlaintext[k] = weightPT;
}
layerWeightsPlaintext[j] = layerNodeWeightsPlaintext;
}
toReturn[i] = layerWeightsPlaintext;
}
return(toReturn);
}
public void EncodeDecodeVectorTest()
{
int slots = 32;
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = (ulong)slots * 2;
List <SmallModulus> coeffModulus = new List <SmallModulus>(4);
coeffModulus.Add(DefaultParams.SmallMods60Bit(0));
coeffModulus.Add(DefaultParams.SmallMods60Bit(1));
coeffModulus.Add(DefaultParams.SmallMods60Bit(2));
coeffModulus.Add(DefaultParams.SmallMods60Bit(3));
parms.CoeffModulus = coeffModulus;
SEALContext context = SEALContext.Create(parms);
CKKSEncoder encoder = new CKKSEncoder(context);
List <Complex> values = new List <Complex>(slots);
Random rnd = new Random();
int dataBound = 1 << 30;
double delta = 1ul << 40;
for (int i = 0; i < slots; i++)
{
values.Add(new Complex(rnd.Next() % dataBound, 0));
}
Plaintext plain = new Plaintext();
encoder.Encode(values, delta, plain);
List <Complex> result = new List <Complex>();
encoder.Decode(plain, result);
for (int i = 0; i < slots; i++)
{
double tmp = Math.Abs(values[i].Real - result[i].Real);
Assert.IsTrue(tmp < 0.5);
}
}
public static List <int> DecryptData(
this List <Ciphertext> ctxs,
Decryptor decryptor,
CKKSEncoder encoder)
{
var result = new List <int>();
foreach (var ctx in ctxs)
{
using var ptx = new Plaintext();
decryptor.Decrypt(ctx, ptx);
var data = new List <double>();
encoder.Decode(ptx, data);
var integers = data.Select(d => (int)d);
result.AddRange(integers);
}
return(result);
}
public ImageProcessorClient()
{
parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = (ulong)PolyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create((ulong)PolyModulusDegree, new int[] { 60, 40, 40, 60 });
double scale = Math.Pow(2.0, 40);
context = new SEALContext(parms);
keygen = new KeyGenerator(context);
secretKey = keygen.SecretKey;
keygen.CreatePublicKey(out PublicKey publicKey);
// keygen.CreateRelinKeys(out RelinKeys relinKeys);
encryptor = new Encryptor(context, publicKey);
evaluator = new Evaluator(context);
decryptor = new Decryptor(context, secretKey);
encoder = new CKKSEncoder(context);
var v1 = Enumerable.Range(0, 2000).Select(e => (double)200);
var v2 = Enumerable.Range(0, 4000).Select(e => (double)200);
var v3 = Enumerable.Range(0, 4096).Select(e => (double)200);
var pd1 = new Plaintext();
var pd2 = new Plaintext();
var pd3 = new Plaintext();
//encoder.Encode(v1, scale, pd1);
//encoder.Encode(v1, scale, pd2);
//encoder.Encode(v1, scale, pd3);
// Pass in encode and evaluator to server.
_imageProcessorServer = new ImageProcessorServer(evaluator, encoder, scale);
}
public void EncodeDecodeVectorTest()
{
int slots = 32;
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
parms.PolyModulusDegree = (ulong)slots * 2;
parms.CoeffModulus = CoeffModulus.Create((ulong)slots * 2, new int[] { 60, 60, 60, 60 });
SEALContext context = new SEALContext(parms,
expandModChain: false,
secLevel: SecLevelType.None);
CKKSEncoder encoder = new CKKSEncoder(context);
List <Complex> values = new List <Complex>(slots);
Random rnd = new Random();
int dataBound = 1 << 30;
double delta = 1ul << 40;
for (int i = 0; i < slots; i++)
{
values.Add(new Complex(rnd.Next() % dataBound, 0));
}
Plaintext plain = new Plaintext();
encoder.Encode(values, delta, plain);
List <Complex> result = new List <Complex>();
encoder.Decode(plain, result);
for (int i = 0; i < slots; i++)
{
double tmp = Math.Abs(values[i].Real - result[i].Real);
Assert.IsTrue(tmp < 0.5);
}
}
static private void ExampleCKKSEncoder()
{
Utilities.PrintExampleBanner("Example: Encoders / CKKS Encoder");
/*
* [CKKSEncoder] (For CKKS scheme only)
*
* In this example we demonstrate the Cheon-Kim-Kim-Song (CKKS) scheme for
* computing on encrypted real or complex numbers. We start by creating
* encryption parameters for the CKKS scheme. There are two important
* differences compared to the BFV scheme:
*
* (1) CKKS does not use the PlainModulus encryption parameter;
* (2) Selecting the CoeffModulus in a specific way can be very important
* when using the CKKS scheme. We will explain this further in the file
* `CKKS_Basics.cs'. In this example we use CoeffModulus.Create to
* generate 5 40-bit prime numbers.
*/
using EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
ulong polyModulusDegree = 8192;
parms.PolyModulusDegree = polyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create(
polyModulusDegree, new int[] { 40, 40, 40, 40, 40 });
/*
* We create the SEALContext as usual and print the parameters.
*/
using SEALContext context = new SEALContext(parms);
Utilities.PrintParameters(context);
Console.WriteLine();
/*
* Keys are created the same way as for the BFV scheme.
*/
using KeyGenerator keygen = new KeyGenerator(context);
using SecretKey secretKey = keygen.SecretKey;
keygen.CreatePublicKey(out PublicKey publicKey);
keygen.CreateRelinKeys(out RelinKeys relinKeys);
/*
* We also set up an Encryptor, Evaluator, and Decryptor as usual.
*/
using Encryptor encryptor = new Encryptor(context, publicKey);
using Evaluator evaluator = new Evaluator(context);
using Decryptor decryptor = new Decryptor(context, secretKey);
/*
* To create CKKS plaintexts we need a special encoder: there is no other way
* to create them. The BatchEncoder cannot be used with the
* CKKS scheme. The CKKSEncoder encodes vectors of real or complex numbers into
* Plaintext objects, which can subsequently be encrypted. At a high level this
* looks a lot like what BatchEncoder does for the BFV scheme, but the theory
* behind it is completely different.
*/
using CKKSEncoder encoder = new CKKSEncoder(context);
/*
* In CKKS the number of slots is PolyModulusDegree / 2 and each slot encodes
* one real or complex number. This should be contrasted with BatchEncoder in
* the BFV scheme, where the number of slots is equal to PolyModulusDegree
* and they are arranged into a matrix with two rows.
*/
ulong slotCount = encoder.SlotCount;
Console.WriteLine($"Number of slots: {slotCount}");
/*
* We create a small vector to encode; the CKKSEncoder will implicitly pad it
* with zeros to full size (PolyModulusDegree / 2) when encoding.
*/
double[] input = new double[] { 0.0, 1.1, 2.2, 3.3 };
Console.WriteLine("Input vector: ");
Utilities.PrintVector(input);
/*
* Now we encode it with CKKSEncoder. The floating-point coefficients of `input'
* will be scaled up by the parameter `scale'. This is necessary since even in
* the CKKS scheme the plaintext elements are fundamentally polynomials with
* integer coefficients. It is instructive to think of the scale as determining
* the bit-precision of the encoding; naturally it will affect the precision of
* the result.
*
* In CKKS the message is stored modulo CoeffModulus (in BFV it is stored modulo
* PlainModulus), so the scaled message must not get too close to the total size
* of CoeffModulus. In this case our CoeffModulus is quite large (200 bits) so
* we have little to worry about in this regard. For this simple example a 30-bit
* scale is more than enough.
*/
using Plaintext plain = new Plaintext();
double scale = Math.Pow(2.0, 30);
Utilities.PrintLine();
Console.WriteLine("Encode input vector.");
encoder.Encode(input, scale, plain);
/*
* We can instantly decode to check the correctness of encoding.
*/
List <double> output = new List <double>();
Console.WriteLine(" + Decode input vector ...... Correct.");
encoder.Decode(plain, output);
Utilities.PrintVector(output);
/*
* The vector is encrypted the same was as in BFV.
*/
using Ciphertext encrypted = new Ciphertext();
Utilities.PrintLine();
Console.WriteLine("Encrypt input vector, square, and relinearize.");
encryptor.Encrypt(plain, encrypted);
/*
* Basic operations on the ciphertexts are still easy to do. Here we square
* the ciphertext, decrypt, decode, and print the result. We note also that
* decoding returns a vector of full size (PolyModulusDegree / 2); this is
* because of the implicit zero-padding mentioned above.
*/
evaluator.SquareInplace(encrypted);
evaluator.RelinearizeInplace(encrypted, relinKeys);
/*
* We notice that the scale in the result has increased. In fact, it is now
* the square of the original scale: 2^60.
*/
Console.WriteLine(" + Scale in squared input: {0} ({1} bits)",
encrypted.Scale,
(int)Math.Ceiling(Math.Log(encrypted.Scale, newBase: 2)));
Utilities.PrintLine();
Console.WriteLine("Decrypt and decode.");
decryptor.Decrypt(encrypted, plain);
encoder.Decode(plain, output);
Console.WriteLine(" + Result vector ...... Correct.");
Utilities.PrintVector(output);
/*
* The CKKS scheme allows the scale to be reduced between encrypted computations.
* This is a fundamental and critical feature that makes CKKS very powerful and
* flexible. We will discuss it in great detail in `3_Levels.cs' and later in
* `4_CKKS_Basics.cs'.
*/
}
private static void CKKSPerformanceTest(SEALContext context)
{
Stopwatch timer;
Utilities.PrintParameters(context);
Console.WriteLine();
bool hasZLIB = Serialization.IsSupportedComprMode(ComprModeType.ZLIB);
bool hasZSTD = Serialization.IsSupportedComprMode(ComprModeType.ZSTD);
using EncryptionParameters parms = context.FirstContextData.Parms;
ulong polyModulusDegree = parms.PolyModulusDegree;
Console.Write("Generating secret/public keys: ");
using KeyGenerator keygen = new KeyGenerator(context);
Console.WriteLine("Done");
using SecretKey secretKey = keygen.SecretKey;
keygen.CreatePublicKey(out PublicKey publicKey);
Func <RelinKeys> GetRelinKeys = () => {
if (context.UsingKeyswitching)
{
/*
* Generate relinearization keys.
*/
Console.Write("Generating relinearization keys: ");
timer = Stopwatch.StartNew();
keygen.CreateRelinKeys(out RelinKeys relinKeys);
int micros = (int)(timer.Elapsed.TotalMilliseconds * 1000);
Console.WriteLine($"Done [{micros} microseconds]");
return(relinKeys);
}
else
{
return(null);
}
};
Func <GaloisKeys> GetGaloisKeys = () => {
if (context.UsingKeyswitching)
{
if (!context.KeyContextData.Qualifiers.UsingBatching)
{
Console.WriteLine("Given encryption parameters do not support batching.");
return(null);
}
/*
* Generate Galois keys. In larger examples the Galois keys can use a lot of
* memory, which can be a problem in constrained systems. The user should
* try some of the larger runs of the test and observe their effect on the
* memory pool allocation size. The key generation can also take a long time,
* as can be observed from the print-out.
*/
Console.Write($"Generating Galois keys: ");
timer = Stopwatch.StartNew();
keygen.CreateGaloisKeys(out GaloisKeys galoisKeys);
int micros = (int)(timer.Elapsed.TotalMilliseconds * 1000);
Console.WriteLine($"Done [{micros} microseconds]");
return(galoisKeys);
}
else
{
return(null);
}
};
using RelinKeys relinKeys = GetRelinKeys();
using GaloisKeys galKeys = GetGaloisKeys();
using Encryptor encryptor = new Encryptor(context, publicKey);
using Decryptor decryptor = new Decryptor(context, secretKey);
using Evaluator evaluator = new Evaluator(context);
using CKKSEncoder ckksEncoder = new CKKSEncoder(context);
Stopwatch timeEncodeSum = new Stopwatch();
Stopwatch timeDecodeSum = new Stopwatch();
Stopwatch timeEncryptSum = new Stopwatch();
Stopwatch timeDecryptSum = new Stopwatch();
Stopwatch timeAddSum = new Stopwatch();
Stopwatch timeMultiplySum = new Stopwatch();
Stopwatch timeMultiplyPlainSum = new Stopwatch();
Stopwatch timeSquareSum = new Stopwatch();
Stopwatch timeRelinearizeSum = new Stopwatch();
Stopwatch timeRescaleSum = new Stopwatch();
Stopwatch timeRotateOneStepSum = new Stopwatch();
Stopwatch timeRotateRandomSum = new Stopwatch();
Stopwatch timeConjugateSum = new Stopwatch();
Stopwatch timeSerializeSum = new Stopwatch();
Stopwatch timeSerializeZLIBSum = new Stopwatch();
Stopwatch timeSerializeZSTDSum = new Stopwatch();
Random rnd = new Random();
/*
* How many times to run the test?
*/
int count = 10;
/*
* Populate a vector of floating-point values to batch.
*/
ulong slotCount = ckksEncoder.SlotCount;
double[] podValues = new double[slotCount];
for (ulong i = 0; i < slotCount; i++)
{
podValues[i] = 1.001 * i;
}
Console.Write("Running tests ");
for (int i = 0; i < count; i++)
{
/*
* [Encoding]
* For scale we use the square root of the last CoeffModulus prime
* from parms.
*/
double scale = Math.Sqrt(parms.CoeffModulus.Last().Value);
using Plaintext plain = new Plaintext(parms.PolyModulusDegree *
(ulong)parms.CoeffModulus.Count(), 0);
timeEncodeSum.Start();
ckksEncoder.Encode(podValues, scale, plain);
timeEncodeSum.Stop();
/*
* [Decoding]
*/
List <double> podList = new List <double>((int)slotCount);
timeDecodeSum.Start();
ckksEncoder.Decode(plain, podList);
timeDecodeSum.Stop();
/*
* [Encryption]
*/
using Ciphertext encrypted = new Ciphertext(context);
timeEncryptSum.Start();
encryptor.Encrypt(plain, encrypted);
timeEncryptSum.Stop();
/*
* [Decryption]
*/
using Plaintext plain2 = new Plaintext(polyModulusDegree, 0);
timeDecryptSum.Start();
decryptor.Decrypt(encrypted, plain2);
timeDecryptSum.Stop();
/*
* [Add]
*/
using Ciphertext encrypted1 = new Ciphertext(context);
ckksEncoder.Encode(i + 1, plain);
encryptor.Encrypt(plain, encrypted1);
using Ciphertext encrypted2 = new Ciphertext(context);
ckksEncoder.Encode(i + 1, plain2);
encryptor.Encrypt(plain2, encrypted2);
timeAddSum.Start();
evaluator.AddInplace(encrypted1, encrypted2);
evaluator.AddInplace(encrypted2, encrypted2);
evaluator.AddInplace(encrypted1, encrypted2);
timeAddSum.Stop();
/*
* [Multiply]
*/
encrypted1.Reserve(3);
timeMultiplySum.Start();
evaluator.MultiplyInplace(encrypted1, encrypted2);
timeMultiplySum.Stop();
/*
* [Multiply Plain]
*/
timeMultiplyPlainSum.Start();
evaluator.MultiplyPlainInplace(encrypted2, plain);
timeMultiplyPlainSum.Stop();
/*
* [Square]
*/
timeSquareSum.Start();
evaluator.SquareInplace(encrypted2);
timeSquareSum.Stop();
if (context.UsingKeyswitching)
{
/*
* [Relinearize]
*/
timeRelinearizeSum.Start();
evaluator.RelinearizeInplace(encrypted1, relinKeys);
timeRelinearizeSum.Stop();
/*
* [Rescale]
*/
timeRescaleSum.Start();
evaluator.RescaleToNextInplace(encrypted1);
timeRescaleSum.Stop();
/*
* [Rotate Vector]
*/
timeRotateOneStepSum.Start();
evaluator.RotateVectorInplace(encrypted, 1, galKeys);
evaluator.RotateVectorInplace(encrypted, -1, galKeys);
timeRotateOneStepSum.Stop();
/*
* [Rotate Vector Random]
*/
// ckksEncoder.SlotCount is always a power of 2.
int randomRotation = rnd.Next() & ((int)ckksEncoder.SlotCount - 1);
timeRotateRandomSum.Start();
evaluator.RotateVectorInplace(encrypted, randomRotation, galKeys);
timeRotateRandomSum.Stop();
/*
* [Complex Conjugate]
*/
timeConjugateSum.Start();
evaluator.ComplexConjugateInplace(encrypted, galKeys);
timeConjugateSum.Stop();
}
/*
* [Serialize Ciphertext]
*/
using MemoryStream stream = new MemoryStream();
timeSerializeSum.Start();
encrypted.Save(stream, ComprModeType.None);
timeSerializeSum.Stop();
if (hasZLIB)
{
/*
* [Serialize Ciphertext (ZLIB)]
*/
timeSerializeZLIBSum.Start();
encrypted.Save(stream, ComprModeType.ZLIB);
timeSerializeZLIBSum.Stop();
}
if (hasZSTD)
{
/*
* [Serialize Ciphertext (Zstandard)]
*/
timeSerializeZSTDSum.Start();
encrypted.Save(stream, ComprModeType.ZSTD);
timeSerializeZSTDSum.Stop();
}
/*
* Print a dot to indicate progress.
*/
Console.Write(".");
Console.Out.Flush();
}
Console.WriteLine(" Done");
Console.WriteLine();
Console.Out.Flush();
int avgEncode = (int)(timeEncodeSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgDecode = (int)(timeDecodeSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgEncrypt = (int)(timeEncryptSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgDecrypt = (int)(timeDecryptSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgAdd = (int)(timeAddSum.Elapsed.TotalMilliseconds * 1000 / (3 * count));
int avgMultiply = (int)(timeMultiplySum.Elapsed.TotalMilliseconds * 1000 / count);
int avgMultiplyPlain = (int)(timeMultiplyPlainSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgSquare = (int)(timeSquareSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgRelinearize = (int)(timeRelinearizeSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgRescale = (int)(timeRescaleSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgRotateOneStep = (int)(timeRotateOneStepSum.Elapsed.TotalMilliseconds * 1000 / (2 * count));
int avgRotateRandom = (int)(timeRotateRandomSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgConjugate = (int)(timeConjugateSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgSerializeSum = (int)(timeSerializeSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgSerializeZLIBSum = (int)(timeSerializeZLIBSum.Elapsed.TotalMilliseconds * 1000 / count);
int avgSerializeZSTDSum = (int)(timeSerializeZSTDSum.Elapsed.TotalMilliseconds * 1000 / count);
Console.WriteLine($"Average encode: {avgEncode} microseconds");
Console.WriteLine($"Average decode: {avgDecode} microseconds");
Console.WriteLine($"Average encrypt: {avgEncrypt} microseconds");
Console.WriteLine($"Average decrypt: {avgDecrypt} microseconds");
Console.WriteLine($"Average add: {avgAdd} microseconds");
Console.WriteLine($"Average multiply: {avgMultiply} microseconds");
Console.WriteLine($"Average multiply plain: {avgMultiplyPlain} microseconds");
Console.WriteLine($"Average square: {avgSquare} microseconds");
if (context.UsingKeyswitching)
{
Console.WriteLine($"Average relinearize: {avgRelinearize} microseconds");
Console.WriteLine($"Average rescale: {avgRescale} microseconds");
Console.WriteLine($"Average rotate vector one step: {avgRotateOneStep} microseconds");
Console.WriteLine($"Average rotate vector random: {avgRotateRandom} microseconds");
Console.WriteLine($"Average complex conjugate: {avgConjugate} microseconds");
}
Console.WriteLine($"Average serialize ciphertext: {avgSerializeSum} microseconds");
if (hasZLIB)
{
Console.WriteLine(
$"Average compressed (ZLIB) serialize ciphertext: {avgSerializeZLIBSum} microseconds");
}
if (hasZSTD)
{
Console.WriteLine(
$"Average compressed (Zstandard) serialize ciphertext: {avgSerializeZSTDSum} microseconds");
}
Console.Out.Flush();
}
private static void ExampleCKKSBasics()
{
Utilities.PrintExampleBanner("Example: CKKS Basics");
/*
* In this example we demonstrate evaluating a polynomial function
*
* PI*x^3 + 0.4*x + 1
*
* on encrypted floating-point input data x for a set of 4096 equidistant points
* in the interval [0, 1]. This example demonstrates many of the main features
* of the CKKS scheme, but also the challenges in using it.
*
* We start by setting up the CKKS scheme.
*/
using EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
/*
* We saw in `2_Encoders.cs' that multiplication in CKKS causes scales in
* ciphertexts to grow. The scale of any ciphertext must not get too close to
* the total size of CoeffModulus, or else the ciphertext simply runs out of
* room to store the scaled-up plaintext. The CKKS scheme provides a `rescale'
* functionality that can reduce the scale, and stabilize the scale expansion.
*
* Rescaling is a kind of modulus switch operation (recall `3_Levels.cs').
* As modulus switching, it removes the last of the primes from CoeffModulus,
* but as a side-effect it scales down the ciphertext by the removed prime.
* Usually we want to have perfect control over how the scales are changed,
* which is why for the CKKS scheme it is more common to use carefully selected
* primes for the CoeffModulus.
*
* More precisely, suppose that the scale in a CKKS ciphertext is S, and the
* last prime in the current CoeffModulus (for the ciphertext) is P. Rescaling
* to the next level changes the scale to S/P, and removes the prime P from the
* CoeffModulus, as usual in modulus switching. The number of primes limits
* how many rescalings can be done, and thus limits the multiplicative depth of
* the computation.
*
* It is possible to choose the initial scale freely. One good strategy can be
* to is to set the initial scale S and primes P_i in the CoeffModulus to be
* very close to each other. If ciphertexts have scale S before multiplication,
* they have scale S^2 after multiplication, and S^2/P_i after rescaling. If all
* P_i are close to S, then S^2/P_i is close to S again. This way we stabilize the
* scales to be close to S throughout the computation. Generally, for a circuit
* of depth D, we need to rescale D times, i.e., we need to be able to remove D
* primes from the coefficient modulus. Once we have only one prime left in the
* coeff_modulus, the remaining prime must be larger than S by a few bits to
* preserve the pre-decimal-point value of the plaintext.
*
* Therefore, a generally good strategy is to choose parameters for the CKKS
* scheme as follows:
*
* (1) Choose a 60-bit prime as the first prime in CoeffModulus. This will
* give the highest precision when decrypting;
* (2) Choose another 60-bit prime as the last element of CoeffModulus, as
* this will be used as the special prime and should be as large as the
* largest of the other primes;
* (3) Choose the intermediate primes to be close to each other.
*
* We use CoeffModulus.Create to generate primes of the appropriate size. Note
* that our CoeffModulus is 200 bits total, which is below the bound for our
* PolyModulusDegree: CoeffModulus.MaxBitCount(8192) returns 218.
*/
ulong polyModulusDegree = 8192;
parms.PolyModulusDegree = polyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create(
polyModulusDegree, new int[] { 60, 40, 40, 60 });
/*
* We choose the initial scale to be 2^40. At the last level, this leaves us
* 60-40=20 bits of precision before the decimal point, and enough (roughly
* 10-20 bits) of precision after the decimal point. Since our intermediate
* primes are 40 bits (in fact, they are very close to 2^40), we can achieve
* scale stabilization as described above.
*/
double scale = Math.Pow(2.0, 40);
using SEALContext context = new SEALContext(parms);
Utilities.PrintParameters(context);
Console.WriteLine();
using KeyGenerator keygen = new KeyGenerator(context);
using PublicKey publicKey = keygen.PublicKey;
using SecretKey secretKey = keygen.SecretKey;
using RelinKeys relinKeys = keygen.RelinKeysLocal();
using Encryptor encryptor = new Encryptor(context, publicKey);
using Evaluator evaluator = new Evaluator(context);
using Decryptor decryptor = new Decryptor(context, secretKey);
using CKKSEncoder encoder = new CKKSEncoder(context);
ulong slotCount = encoder.SlotCount;
Console.WriteLine($"Number of slots: {slotCount}");
List <double> input = new List <double>((int)slotCount);
double currPoint = 0, stepSize = 1.0 / (slotCount - 1);
for (ulong i = 0; i < slotCount; i++, currPoint += stepSize)
{
input.Add(currPoint);
}
Console.WriteLine("Input vector:");
Utilities.PrintVector(input, 3, 7);
Console.WriteLine("Evaluating polynomial PI*x^3 + 0.4x + 1 ...");
/*
* We create plaintexts for PI, 0.4, and 1 using an overload of CKKSEncoder.Encode
* that encodes the given floating-point value to every slot in the vector.
*/
using Plaintext plainCoeff3 = new Plaintext(),
plainCoeff1 = new Plaintext(),
plainCoeff0 = new Plaintext();
encoder.Encode(3.14159265, scale, plainCoeff3);
encoder.Encode(0.4, scale, plainCoeff1);
encoder.Encode(1.0, scale, plainCoeff0);
using Plaintext xPlain = new Plaintext();
Utilities.PrintLine();
Console.WriteLine("Encode input vectors.");
encoder.Encode(input, scale, xPlain);
using Ciphertext x1Encrypted = new Ciphertext();
encryptor.Encrypt(xPlain, x1Encrypted);
/*
* To compute x^3 we first compute x^2 and relinearize. However, the scale has
* now grown to 2^80.
*/
using Ciphertext x3Encrypted = new Ciphertext();
Utilities.PrintLine();
Console.WriteLine("Compute x^2 and relinearize:");
evaluator.Square(x1Encrypted, x3Encrypted);
evaluator.RelinearizeInplace(x3Encrypted, relinKeys);
Console.WriteLine(" + Scale of x^2 before rescale: {0} bits",
Math.Log(x3Encrypted.Scale, newBase: 2));
/*
* Now rescale; in addition to a modulus switch, the scale is reduced down by
* a factor equal to the prime that was switched away (40-bit prime). Hence, the
* new scale should be close to 2^40. Note, however, that the scale is not equal
* to 2^40: this is because the 40-bit prime is only close to 2^40.
*/
Utilities.PrintLine();
Console.WriteLine("Rescale x^2.");
evaluator.RescaleToNextInplace(x3Encrypted);
Console.WriteLine(" + Scale of x^2 after rescale: {0} bits",
Math.Log(x3Encrypted.Scale, newBase: 2));
/*
* Now x3Encrypted is at a different level than x1Encrypted, which prevents us
* from multiplying them to compute x^3. We could simply switch x1Encrypted to
* the next parameters in the modulus switching chain. However, since we still
* need to multiply the x^3 term with PI (plainCoeff3), we instead compute PI*x
* first and multiply that with x^2 to obtain PI*x^3. To this end, we compute
* PI*x and rescale it back from scale 2^80 to something close to 2^40.
*/
Utilities.PrintLine();
Console.WriteLine("Compute and rescale PI*x.");
using Ciphertext x1EncryptedCoeff3 = new Ciphertext();
evaluator.MultiplyPlain(x1Encrypted, plainCoeff3, x1EncryptedCoeff3);
Console.WriteLine(" + Scale of PI*x before rescale: {0} bits",
Math.Log(x1EncryptedCoeff3.Scale, newBase: 2));
evaluator.RescaleToNextInplace(x1EncryptedCoeff3);
Console.WriteLine(" + Scale of PI*x after rescale: {0} bits",
Math.Log(x1EncryptedCoeff3.Scale, newBase: 2));
/*
* Since x3Encrypted and x1EncryptedCoeff3 have the same exact scale and use
* the same encryption parameters, we can multiply them together. We write the
* result to x3Encrypted, relinearize, and rescale. Note that again the scale
* is something close to 2^40, but not exactly 2^40 due to yet another scaling
* by a prime. We are down to the last level in the modulus switching chain.
*/
Utilities.PrintLine();
Console.WriteLine("Compute, relinearize, and rescale (PI*x)*x^2.");
evaluator.MultiplyInplace(x3Encrypted, x1EncryptedCoeff3);
evaluator.RelinearizeInplace(x3Encrypted, relinKeys);
Console.WriteLine(" + Scale of PI*x^3 before rescale: {0} bits",
Math.Log(x3Encrypted.Scale, newBase: 2));
evaluator.RescaleToNextInplace(x3Encrypted);
Console.WriteLine(" + Scale of PI*x^3 after rescale: {0} bits",
Math.Log(x3Encrypted.Scale, newBase: 2));
/*
* Next we compute the degree one term. All this requires is one MultiplyPlain
* with plainCoeff1. We overwrite x1Encrypted with the result.
*/
Utilities.PrintLine();
Console.WriteLine("Compute and rescale 0.4*x.");
evaluator.MultiplyPlainInplace(x1Encrypted, plainCoeff1);
Console.WriteLine(" + Scale of 0.4*x before rescale: {0} bits",
Math.Log(x1Encrypted.Scale, newBase: 2));
evaluator.RescaleToNextInplace(x1Encrypted);
Console.WriteLine(" + Scale of 0.4*x after rescale: {0} bits",
Math.Log(x1Encrypted.Scale, newBase: 2));
/*
* Now we would hope to compute the sum of all three terms. However, there is
* a serious problem: the encryption parameters used by all three terms are
* different due to modulus switching from rescaling.
*
* Encrypted addition and subtraction require that the scales of the inputs are
* the same, and also that the encryption parameters (ParmsId) match. If there
* is a mismatch, Evaluator will throw an exception.
*/
Console.WriteLine();
Utilities.PrintLine();
Console.WriteLine("Parameters used by all three terms are different:");
Console.WriteLine(" + Modulus chain index for x3Encrypted: {0}",
context.GetContextData(x3Encrypted.ParmsId).ChainIndex);
Console.WriteLine(" + Modulus chain index for x1Encrypted: {0}",
context.GetContextData(x1Encrypted.ParmsId).ChainIndex);
Console.WriteLine(" + Modulus chain index for plainCoeff0: {0}",
context.GetContextData(plainCoeff0.ParmsId).ChainIndex);
Console.WriteLine();
/*
* Let us carefully consider what the scales are at this point. We denote the
* primes in coeff_modulus as P_0, P_1, P_2, P_3, in this order. P_3 is used as
* the special modulus and is not involved in rescalings. After the computations
* above the scales in ciphertexts are:
*
* - Product x^2 has scale 2^80 and is at level 2;
* - Product PI*x has scale 2^80 and is at level 2;
* - We rescaled both down to scale 2^80/P2 and level 1;
* - Product PI*x^3 has scale (2^80/P_2)^2;
* - We rescaled it down to scale (2^80/P_2)^2/P_1 and level 0;
* - Product 0.4*x has scale 2^80;
* - We rescaled it down to scale 2^80/P_2 and level 1;
* - The contant term 1 has scale 2^40 and is at level 2.
*
* Although the scales of all three terms are approximately 2^40, their exact
* values are different, hence they cannot be added together.
*/
Utilities.PrintLine();
Console.WriteLine("The exact scales of all three terms are different:");
Console.WriteLine(" + Exact scale in PI*x^3: {0:0.0000000000}", x3Encrypted.Scale);
Console.WriteLine(" + Exact scale in 0.4*x: {0:0.0000000000}", x1Encrypted.Scale);
Console.WriteLine(" + Exact scale in 1: {0:0.0000000000}", plainCoeff0.Scale);
Console.WriteLine();
/*
* There are many ways to fix this problem. Since P_2 and P_1 are really close
* to 2^40, we can simply "lie" to Microsoft SEAL and set the scales to be the
* same. For example, changing the scale of PI*x^3 to 2^40 simply means that we
* scale the value of PI*x^3 by 2^120/(P_2^2*P_1), which is very close to 1.
* This should not result in any noticeable error.
*
* Another option would be to encode 1 with scale 2^80/P_2, do a MultiplyPlain
* with 0.4*x, and finally rescale. In this case we would need to additionally
* make sure to encode 1 with appropriate encryption parameters (ParmsId).
*
* In this example we will use the first (simplest) approach and simply change
* the scale of PI*x^3 and 0.4*x to 2^40.
*/
Utilities.PrintLine();
Console.WriteLine("Normalize scales to 2^40.");
x3Encrypted.Scale = Math.Pow(2.0, 40);
x1Encrypted.Scale = Math.Pow(2.0, 40);
/*
* We still have a problem with mismatching encryption parameters. This is easy
* to fix by using traditional modulus switching (no rescaling). CKKS supports
* modulus switching just like the BFV scheme, allowing us to switch away parts
* of the coefficient modulus when it is simply not needed.
*/
Utilities.PrintLine();
Console.WriteLine("Normalize encryption parameters to the lowest level.");
ParmsId lastParmsId = x3Encrypted.ParmsId;
evaluator.ModSwitchToInplace(x1Encrypted, lastParmsId);
evaluator.ModSwitchToInplace(plainCoeff0, lastParmsId);
/*
* All three ciphertexts are now compatible and can be added.
*/
Utilities.PrintLine();
Console.WriteLine("Compute PI*x^3 + 0.4*x + 1.");
using Ciphertext encryptedResult = new Ciphertext();
evaluator.Add(x3Encrypted, x1Encrypted, encryptedResult);
evaluator.AddPlainInplace(encryptedResult, plainCoeff0);
/*
* First print the true result.
*/
using Plaintext plainResult = new Plaintext();
Utilities.PrintLine();
Console.WriteLine("Decrypt and decode PI * x ^ 3 + 0.4x + 1.");
Console.WriteLine(" + Expected result:");
List <double> trueResult = new List <double>(input.Count);
foreach (double x in input)
{
trueResult.Add((3.14159265 * x * x + 0.4) * x + 1);
}
Utilities.PrintVector(trueResult, 3, 7);
/*
* We decrypt, decode, and print the result.
*/
decryptor.Decrypt(encryptedResult, plainResult);
List <double> result = new List <double>();
encoder.Decode(plainResult, result);
Console.WriteLine(" + Computed result ...... Correct.");
Utilities.PrintVector(result, 3, 7);
/*
* While we did not show any computations on complex numbers in these examples,
* the CKKSEncoder would allow us to have done that just as easily. Additions
* and multiplications of complex numbers behave just as one would expect.
*/
}
public int Predict(double[] features, int power, bool useRelinearizeInplace, bool useReScale, Stopwatch timePredictSum)
{
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
if (power < 60)
{
ulong polyModulusDegree = 8192;
parms.PolyModulusDegree = polyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree, new int[] { 60, 40, 40, 60 });
}
else
{
ulong polyModulusDegree = 16384;
parms.PolyModulusDegree = polyModulusDegree;
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree, new int[] { 60, 60, 60, 60, 60, 60 });
}
//
double scale = Math.Pow(2.0, power);
SEALContext context = new SEALContext(parms);
Console.WriteLine();
KeyGenerator keygen = new KeyGenerator(context);
PublicKey publicKey = keygen.PublicKey;
SecretKey secretKey = keygen.SecretKey;
RelinKeys relinKeys = keygen.RelinKeys();
Encryptor encryptor = new Encryptor(context, publicKey);
Evaluator evaluator = new Evaluator(context);
Decryptor decryptor = new Decryptor(context, secretKey);
CKKSEncoder encoder = new CKKSEncoder(context);
ulong slotCount = encoder.SlotCount;
Console.WriteLine($"Number of slots: {slotCount}");
timePredictSum.Start();
var featuresLength = features.Length;
var plaintexts = new Plaintext[featuresLength];
var featuresCiphertexts = new Ciphertext[featuresLength];
//Encode and encrypt features
for (int i = 0; i < featuresLength; i++)
{
plaintexts[i] = new Plaintext();
encoder.Encode(features[i], scale, plaintexts[i]);
SvcUtilities.PrintScale(plaintexts[i], "featurePlaintext" + i);
featuresCiphertexts[i] = new Ciphertext();
encryptor.Encrypt(plaintexts[i], featuresCiphertexts[i]);
SvcUtilities.PrintScale(featuresCiphertexts[i], "featurefEncrypted" + i);
}
// Handle SV
var numOfrows = _vectors.Length;
var numOfcolumns = _vectors[0].Length;
var svPlaintexts = new Plaintext[numOfrows, numOfcolumns];
//Encode SV
for (int i = 0; i < numOfrows; i++)
{
for (int j = 0; j < numOfcolumns; j++)
{
svPlaintexts[i, j] = new Plaintext();
encoder.Encode(_vectors[i][j], scale, svPlaintexts[i, j]);
SvcUtilities.PrintScale(svPlaintexts[i, j], "supportVectorsPlaintext" + i + j);
}
}
// Prepare sum of inner product
var sums = new Ciphertext[numOfcolumns];
for (int i = 0; i < numOfcolumns; i++)
{
sums[i] = new Ciphertext();
}
var kernels = new Ciphertext[numOfrows];
var decisionsArr = new Ciphertext[numOfrows];
var coefArr = new Plaintext [numOfrows];
for (int i = 0; i < numOfrows; i++)
{
kernels[i] = new Ciphertext();
decisionsArr[i] = new Ciphertext();
coefArr[i] = new Plaintext();
}
// Level 1
for (int i = 0; i < numOfrows; i++)
{
var ciphertexts = new List <Ciphertext>();
//inner product
for (int j = 0; j < numOfcolumns; j++)
{
evaluator.MultiplyPlain(featuresCiphertexts[j], svPlaintexts[i, j], sums[j]);
if (useRelinearizeInplace)
{
evaluator.RelinearizeInplace(sums[j], relinKeys);
}
if (useReScale)
{
evaluator.RescaleToNextInplace(sums[j]);
}
SvcUtilities.PrintScale(sums[j], "tSum" + j);
}
evaluator.AddMany(sums, kernels[i]);
evaluator.NegateInplace(kernels[i]);
SvcUtilities.PrintScale(kernels[i], "kernel" + i);
SvcUtilities.PrintCyprherText(decryptor, kernels[i], encoder, "kernel" + i);
}
// Encode coefficients : ParmsId! , scale!
double scale2 = Math.Pow(2.0, power);
if (useReScale)
{
scale2 = kernels[0].Scale;
}
for (int i = 0; i < numOfrows; i++)
{
encoder.Encode(_coefficients[0][i], scale2, coefArr[i]);
SvcUtilities.PrintScale(coefArr[i], "coefPlainText+i");
}
if (useReScale)
{
for (int i = 0; i < numOfrows; i++)
{
ParmsId lastParmsId = kernels[i].ParmsId;
evaluator.ModSwitchToInplace(coefArr[i], lastParmsId);
}
}
// Level 2
// Calculate decisionArr
for (int i = 0; i < numOfrows; i++)
{
evaluator.MultiplyPlain(kernels[i], coefArr[i], decisionsArr[i]);
if (useRelinearizeInplace)
{
evaluator.RelinearizeInplace(decisionsArr[i], relinKeys);
}
if (useReScale)
{
evaluator.RescaleToNextInplace(decisionsArr[i]);
}
SvcUtilities.PrintScale(decisionsArr[i], "decision" + i);
SvcUtilities.PrintCyprherText(decryptor, decisionsArr[i], encoder, "decision" + i);
}
// Calculate decisionTotal
Ciphertext decisionTotal = new Ciphertext();
//=================================================================
evaluator.AddMany(decisionsArr, decisionTotal);
//=================================================================
SvcUtilities.PrintScale(decisionTotal, "decisionTotal");
SvcUtilities.PrintCyprherText(decryptor, decisionTotal, encoder, "decision total");
// Encode intercepts : ParmsId! , scale!
Plaintext interceptsPlainText = new Plaintext();
double scale3 = Math.Pow(2.0, power * 3);
if (useReScale)
{
scale3 = decisionTotal.Scale;
}
encoder.Encode(_intercepts[0], scale3, interceptsPlainText);
if (useReScale)
{
ParmsId lastParmsId = decisionTotal.ParmsId;
evaluator.ModSwitchToInplace(interceptsPlainText, lastParmsId);
}
SvcUtilities.PrintScale(interceptsPlainText, "interceptsPlainText");
SvcUtilities.PrintScale(decisionTotal, "decisionTotal");
//// Calculate finalTotal
Ciphertext finalTotal = new Ciphertext();
//=================================================================
evaluator.AddPlainInplace(decisionTotal, interceptsPlainText);
//=================================================================
timePredictSum.Stop();
SvcUtilities.PrintScale(decisionTotal, "decisionTotal"); //Level 3
List <double> result = SvcUtilities.PrintCyprherText(decryptor, decisionTotal, encoder, "finalTotal");
using (System.IO.StreamWriter file =
new System.IO.StreamWriter(
$@"{OutputDir}IrisLinear_IrisSecureSVC_total_{power}_{useRelinearizeInplace}_{useReScale}.txt", !_firstTime)
)
{
_firstTime = false;
file.WriteLine($"{result[0]}");
}
if (result[0] > 0)
{
return(0);
}
return(1);
}
//constructor for debugging , because it enables to pass secretkey which will not happen in real life
// special parameters :
// batchsize - number of batches sample in one ciphertext ,if the client batches mulitple samples in the ciphertet .
// featureSize - number of features in sample
private Svc(double[][] vectors, double[][] coefficients, double[] intercepts, String kernel, double gamma, double coef0, ulong degree, int power, PublicKey publicKey, SecretKey secretKey, RelinKeys relinKeys, GaloisKeys galoisKeys, int batchSize, int featureSize)
{
this._vectors = vectors;
this._coefficients = coefficients;
this._intercepts = intercepts;
this._kernel = (Kernel)System.Enum.Parse(typeof(Kernel), kernel);
this._gamma = gamma;
this._coef0 = coef0;
this._degree = degree;
this._power = power;
//Use the ckks SCheme
EncryptionParameters parms = new EncryptionParameters(SchemeType.CKKS);
// polyModulusDegree and CoeffModulus used for general SVM algorithm and depends on the polynomial kernel degree
// ( and the percision constraint ) .
// My implementation can be used up to dgree = 4 , but it can be easly refactored with some oprimizations to higher
// polynomial degree
ulong polyModulusDegree = 16384;
if (power >= 20 && power < 40)
{
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree,
new int[] { 60, 20, 21, 22, 23, 24, 25, 26, 27, 60 });
}
else if (power >= 40 && power < 60)
{
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree,
new int[] { 60, 40, 40, 40, 40, 40, 40, 40, 60 });
}
else if (power == 60)
{
polyModulusDegree = 32768;
parms.CoeffModulus = CoeffModulus.Create(polyModulusDegree,
new int[] { 60, 60, 60, 60, 60, 60, 60, 60, 60 });
}
parms.PolyModulusDegree = polyModulusDegree;
_context = new SEALContext(parms);
_publicKey = publicKey;
_secretKey = secretKey;
_relinKeys = relinKeys;
_galoisKeys = galoisKeys;
_evaluator = new Evaluator(_context);
if (_secretKey != null)
{
_decryptor = new Decryptor(_context, _secretKey); //FOR DEBUG ONLY ( not used in real server)
}
_encoder = new CKKSEncoder(_context);
Stopwatch serverInitStopwatch = new Stopwatch();
serverInitStopwatch.Start();
_numOfrowsCount = _vectors.Length; //Number of Support Vectors
_numOfcolumnsCount = _vectors[0].Length; //Number of features in every Support vector
_scale = Math.Pow(2.0, _power);
// vars for batch rotations
_svPlaintexts = new Plaintext[_numOfrowsCount];
//Encode support vectors
_sums = new Ciphertext[_numOfrowsCount];
if (UseBatchInnerProduct)
{
double[] batchVectors = new double[batchSize * featureSize];
for (int i = 0; i < _numOfrowsCount; i++)
{
for (int k = 0; k < batchSize * featureSize; k++)
{
var index0 = k % featureSize;
batchVectors[k] = index0 < _numOfcolumnsCount ? _vectors[i][index0] : 0;
}
_svPlaintexts[i] = new Plaintext();
_encoder.Encode(batchVectors, _scale, _svPlaintexts[i]);
SVCUtilities.SvcUtilities.PrintScale(_svPlaintexts[i], "batch supportVectorsPlaintext" + i);
_sums[i] = new Ciphertext();
}
}
else
{
/////////////////////////////////////////////////////////////////////////
//
// vars for simple inner product
//
// Handle SV
_svPlaintextsArr = new Plaintext[_numOfrowsCount, _numOfcolumnsCount];
//Encode SV
for (int i = 0; i < _numOfrowsCount; i++)
{
for (int j = 0; j < _numOfcolumnsCount; j++)
{
_svPlaintextsArr[i, j] = new Plaintext();
_encoder.Encode(_vectors[i][j] != 0 ? _vectors[i][j] : Zero, _scale, _svPlaintextsArr[i, j]);
SvcUtilities.PrintScale(_svPlaintextsArr[i, j], $"supportVectorsPlaintext[{i}][{j}]");
}
}
// Prepare sum of inner product
_innerProdSums = new Ciphertext[_numOfcolumnsCount];
for (int i = 0; i < _numOfcolumnsCount; i++)
{
_innerProdSums[i] = new Ciphertext();
}
//////////////////////////////////////////////////////////////
}
// Allocate memory for svm secure calculation
_kernels = new Ciphertext[_numOfrowsCount];
_decisionsArr = new Ciphertext[_numOfrowsCount];
_coefArr = new Plaintext[_numOfrowsCount];
for (int i = 0; i < _numOfrowsCount; i++)
{
_kernels[i] = new Ciphertext();
_decisionsArr[i] = new Ciphertext();
_coefArr[i] = new Plaintext();
}
_gamaPlaintext = new Plaintext();
_encoder.Encode(_gamma != 0 ? _gamma : Zero, _scale, _gamaPlaintext);
serverInitStopwatch.Stop();
Console.WriteLine($"server Init elapsed {serverInitStopwatch.ElapsedMilliseconds} ms");
}
