org.bouncycastle.pqc.crypto.crystals.kyber.KyberIndCpa Maven / Gradle / Ivy
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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.8 and up.
package org.bouncycastle.pqc.crypto.crystals.kyber;
import org.bouncycastle.crypto.digests.SHAKEDigest;
import org.bouncycastle.util.Arrays;
class KyberIndCpa
{
private KyberEngine engine;
private int kyberK;
private int eta1;
private int indCpaPublicKeyBytes;
private int polyVecBytes;
private int indCpaBytes;
private int polyVecCompressedBytes;
private int polyCompressedBytes;
private Symmetric symmetric;
public KyberIndCpa(KyberEngine engine)
{
this.engine = engine;
this.kyberK = engine.getKyberK();
this.eta1 = engine.getKyberEta1();
this.indCpaPublicKeyBytes = engine.getKyberPublicKeyBytes();
this.polyVecBytes = engine.getKyberPolyVecBytes();
this.indCpaBytes = engine.getKyberIndCpaBytes();
this.polyVecCompressedBytes = engine.getKyberPolyVecCompressedBytes();
this.polyCompressedBytes = engine.getKyberPolyCompressedBytes();
this.symmetric = engine.getSymmetric();
KyberGenerateMatrixNBlocks =
(
(
12 * KyberEngine.KyberN
/ 8 * (1 << 12)
/ KyberEngine.KyberQ + symmetric.xofBlockBytes
)
/ symmetric.xofBlockBytes
);
}
/**
* Generates IndCpa Key Pair
*
* @return KeyPair where each key is represented as bytes
*/
public byte[][] generateKeyPair()
{
PolyVec secretKey = new PolyVec(engine),
publicKey = new PolyVec(engine),
e = new PolyVec(engine);
byte[] d = new byte[32];
// (p, sigma) <- G(d)
engine.getRandomBytes(d);
byte[] buf = new byte[64];
symmetric.hash_g(buf, d);
byte[] publicSeed = new byte[32]; // p in docs
byte[] noiseSeed = new byte[32]; // sigma in docs
System.arraycopy(buf, 0, publicSeed, 0, 32);
System.arraycopy(buf, 32, noiseSeed, 0, 32);
byte count = (byte)0;
// Helper.printByteArray(buf);
PolyVec[] aMatrix = new PolyVec[kyberK];
int i;
for (i = 0; i < kyberK; i++)
{
aMatrix[i] = new PolyVec(engine);
}
generateMatrix(aMatrix, publicSeed, false);
// System.out.println("aMatrix = ");
// for(i = 0; i < kyberK; i++) {
// System.out.print("[");
// for (int j = 0; j < kyberK; j++) {
// System.out.print("[");
// for (int k = 0; k < KyberEngine.KyberN; k++) {
// System.out.printf("%d ,", aMatrix[i].getVectorIndex(j).getCoeffIndex(k));
// }
// System.out.print("], \n");
// }
// System.out.print("]\n");
// }
for (i = 0; i < kyberK; i++)
{
secretKey.getVectorIndex(i).getEta1Noise(noiseSeed, count);
// System.out.print("SecretKeyPolyVec["+i+"] = [");
// for (int j =0; j < KyberEngine.KyberN; j++) {
// System.out.print(secretKey.getVectorIndex(i).getCoeffIndex(j) + ", ");
// }
// System.out.println("]");
count = (byte)(count + (byte)1);
}
for (i = 0; i < kyberK; i++)
{
e.getVectorIndex(i).getEta1Noise(noiseSeed, count);
count = (byte)(count + (byte)1);
}
secretKey.polyVecNtt();
// System.out.print("SecretKeyPolyVec = [");
// for (i = 0; i < kyberK; i++) {
// System.out.print("[");
// for (int j =0; j < KyberEngine.KyberN; j++) {
// System.out.print(secretKey.getVectorIndex(i).getCoeffIndex(j) + ", ");
// }
// System.out.println("],");
// }
// System.out.println("]");
e.polyVecNtt();
for (i = 0; i < kyberK; i++)
{
PolyVec.pointwiseAccountMontgomery(publicKey.getVectorIndex(i), aMatrix[i], secretKey, engine);
publicKey.getVectorIndex(i).convertToMont();
}
// System.out.print("PublicKey PolyVec = [");
// Helper.printPolyVec(publicKey, kyberK);
publicKey.addPoly(e);
publicKey.reducePoly();
return new byte[][]{packPublicKey(publicKey, publicSeed), packSecretKey(secretKey)};
}
public byte[] encrypt(byte[] msg, byte[] publicKeyInput, byte[] coins)
{
int i;
byte[] seed;
byte nonce = (byte)0;
PolyVec sp = new PolyVec(engine),
publicKeyPolyVec = new PolyVec(engine),
errorPolyVector = new PolyVec(engine),
bp = new PolyVec(engine);
PolyVec[] aMatrixTranspose = new PolyVec[engine.getKyberK()];
Poly errorPoly = new Poly(engine),
v = new Poly(engine),
k = new Poly(engine);
// System.out.print("publickeyinput = ");
// Helper.printByteArray(publicKeyInput);
// System.out.println();
seed = unpackPublicKey(publicKeyPolyVec, publicKeyInput);
// System.out.print("publickeyPolyVec = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(publicKeyPolyVec.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
// System.out.print("seed = ");
// Helper.printByteArray(seed);
// System.out.println();
k.fromMsg(msg);
for (i = 0; i < kyberK; i++)
{
aMatrixTranspose[i] = new PolyVec(engine);
}
generateMatrix(aMatrixTranspose, seed, true);
// System.out.print("matrix transposed = ");
// for (i = 0; i < kyberK; i++) {
// System.out.print("[");
// for(int j = 0; j < kyberK; j++) {
// System.out.print("[");
// for (int l = 0; l < 256; l++) {
// System.out.printf("%d ,", aMatrixTranspose[i].getVectorIndex(j).getCoeffIndex(l));
// }
// System.out.print("] ,\n");
// }
// System.out.println("] ,");
// }
for (i = 0; i < kyberK; i++)
{
sp.getVectorIndex(i).getEta1Noise(coins, nonce);
nonce = (byte)(nonce + (byte)1);
}
for (i = 0; i < kyberK; i++)
{
errorPolyVector.getVectorIndex(i).getEta2Noise(coins, nonce);
nonce = (byte)(nonce + (byte)1);
}
errorPoly.getEta2Noise(coins, nonce);
sp.polyVecNtt();
// System.out.print("sp = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(sp.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
// System.out.print("sp = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(sp.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
for (i = 0; i < kyberK; i++)
{
PolyVec.pointwiseAccountMontgomery(bp.getVectorIndex(i), aMatrixTranspose[i], sp, engine);
}
// System.out.print("bp = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(bp.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
PolyVec.pointwiseAccountMontgomery(v, publicKeyPolyVec, sp, engine);
bp.polyVecInverseNttToMont();
v.polyInverseNttToMont();
bp.addPoly(errorPolyVector);
v.addCoeffs(errorPoly);
v.addCoeffs(k);
bp.reducePoly();
v.reduce();
// System.out.print("bp = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(bp.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
// System.out.print("v = ");
// Helper.printShortArray(v.getCoeffs());
// System.out.println();
byte[] outputCipherText = packCipherText(bp, v);
return outputCipherText;
}
private byte[] packCipherText(PolyVec b, Poly v)
{
byte[] outBuf = new byte[indCpaBytes];
System.arraycopy(b.compressPolyVec(), 0, outBuf, 0, polyVecCompressedBytes);
System.arraycopy(v.compressPoly(), 0, outBuf, polyVecCompressedBytes, polyCompressedBytes);
// System.out.print("outBuf = [");
// Helper.printByteArray(outBuf);
return outBuf;
}
private void unpackCipherText(PolyVec b, Poly v, byte[] cipherText)
{
byte[] compressedPolyVecCipherText = Arrays.copyOfRange(cipherText, 0, engine.getKyberPolyVecCompressedBytes());
b.decompressPolyVec(compressedPolyVecCipherText);
byte[] compressedPolyCipherText = Arrays.copyOfRange(cipherText, engine.getKyberPolyVecCompressedBytes(), cipherText.length);
v.decompressPoly(compressedPolyCipherText);
}
public byte[] packPublicKey(PolyVec publicKeyPolyVec, byte[] seed)
{
byte[] buf = new byte[indCpaPublicKeyBytes];
System.arraycopy(publicKeyPolyVec.toBytes(), 0, buf, 0, polyVecBytes);
System.arraycopy(seed, 0, buf, polyVecBytes, KyberEngine.KyberSymBytes);
return buf;
}
public byte[] unpackPublicKey(PolyVec publicKeyPolyVec, byte[] publicKey)
{
byte[] outputSeed = new byte[KyberEngine.KyberSymBytes];
publicKeyPolyVec.fromBytes(publicKey);
System.arraycopy(publicKey, polyVecBytes, outputSeed, 0, KyberEngine.KyberSymBytes);
return outputSeed;
}
public byte[] packSecretKey(PolyVec secretKeyPolyVec)
{
return secretKeyPolyVec.toBytes();
}
public void unpackSecretKey(PolyVec secretKeyPolyVec, byte[] secretKey)
{
secretKeyPolyVec.fromBytes(secretKey);
}
public final int KyberGenerateMatrixNBlocks;
public void generateMatrix(PolyVec[] aMatrix, byte[] seed, boolean transposed)
{
int i, j, k, ctr, off;
SHAKEDigest kyberXOF;
byte[] buf = new byte[KyberGenerateMatrixNBlocks * symmetric.xofBlockBytes + 2];
for (i = 0; i < kyberK; i++)
{
for (j = 0; j < kyberK; j++)
{
if (transposed)
{
symmetric.xofAbsorb(seed, (byte) i, (byte) j);
}
else
{
symmetric.xofAbsorb(seed, (byte) j, (byte) i);
}
symmetric.xofSqueezeBlocks(buf, 0, symmetric.xofBlockBytes * KyberGenerateMatrixNBlocks);
int buflen = KyberGenerateMatrixNBlocks * symmetric.xofBlockBytes;
ctr = rejectionSampling(aMatrix[i].getVectorIndex(j), 0, KyberEngine.KyberN, buf, buflen);
while (ctr < KyberEngine.KyberN)
{
off = buflen % 3;
for (k = 0; k < off; k++)
{
buf[k] = buf[buflen - off + k];
}
symmetric.xofSqueezeBlocks(buf, off, symmetric.xofBlockBytes * 2);
buflen = off + symmetric.xofBlockBytes;
// Error in code Section Unsure
ctr += rejectionSampling(aMatrix[i].getVectorIndex(j), ctr, KyberEngine.KyberN - ctr, buf, buflen);
}
}
}
}
private static int rejectionSampling(Poly outputBuffer, int coeffOff, int len, byte[] inpBuf, int inpBufLen)
{
int ctr, pos;
short val0, val1;
ctr = pos = 0;
while (ctr < len && pos + 3 <= inpBufLen)
{
val0 = (short)(((((short)(inpBuf[pos] & 0xFF)) >> 0) | (((short)(inpBuf[pos + 1] & 0xFF)) << 8)) & 0xFFF);
val1 = (short)(((((short)(inpBuf[pos + 1] & 0xFF)) >> 4) | (((short)(inpBuf[pos + 2] & 0xFF)) << 4)) & 0xFFF);
pos = pos + 3;
if (val0 < (short)KyberEngine.KyberQ)
{
outputBuffer.setCoeffIndex(coeffOff + ctr, (short)val0);
ctr++;
}
if (ctr < len && val1 < (short)KyberEngine.KyberQ)
{
outputBuffer.setCoeffIndex(coeffOff + ctr, (short)val1);
ctr++;
}
}
return ctr;
}
public byte[] decrypt(byte[] cipherText, byte[] secretKey)
{
int i;
byte[] outputMessage = new byte[KyberEngine.getKyberIndCpaMsgBytes()];
PolyVec bp = new PolyVec(engine), secretKeyPolyVec = new PolyVec(engine);
Poly v = new Poly(engine), mp = new Poly(engine);
unpackCipherText(bp, v, cipherText);
// System.out.print("bp = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(bp.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
// System.out.print("v = ");
// Helper.printShortArray(v.getCoeffs());
// System.out.println();
unpackSecretKey(secretKeyPolyVec, secretKey);
// System.out.print("decrypt secretkey = ");;
// Helper.printByteArray(secretKey);
// System.out.print("SecretKeyPolyVec = [");
// for (i = 0; i < kyberK; i++) {
// System.out.print("[");
// for (int j =0; j < KyberEngine.KyberN; j++) {
// System.out.print(secretKeyPolyVec.getVectorIndex(i).getCoeffIndex(j) + ", ");
// }
// System.out.println("],");
// }
// System.out.println("]");
// System.out.print("bp before ntt = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(bp.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
bp.polyVecNtt();
// System.out.print("bp after ntt = [");
// for (i = 0; i < kyberK; i++) {
// Helper.printShortArray(bp.getVectorIndex(i).getCoeffs());
// System.out.print("], \n");
// }
// System.out.println("]");
PolyVec.pointwiseAccountMontgomery(mp, secretKeyPolyVec, bp, engine);
mp.polyInverseNttToMont();
mp.polySubtract(v);
mp.reduce();
outputMessage = mp.toMsg();
return outputMessage;
}
}
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