org.bouncycastle.pqc.crypto.bike.BIKERing 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.bike;
import java.util.HashMap;
import java.util.Map;
import org.bouncycastle.math.raw.Interleave;
import org.bouncycastle.math.raw.Mod;
import org.bouncycastle.math.raw.Nat;
import org.bouncycastle.util.Integers;
import org.bouncycastle.util.Pack;
class BIKERing
{
private static final int PERMUTATION_CUTOFF = 64;
private final int bits;
private final int size;
private final int sizeExt;
private final Map halfPowers = new HashMap();
BIKERing(int r)
{
if ((r & 0xFFFF0001) != 1)
throw new IllegalArgumentException();
bits = r;
size = (r + 63) >>> 6;
sizeExt = size * 2;
generateHalfPowersInv(halfPowers, r);
}
void add(long[] x, long[] y, long[] z)
{
for (int i = 0; i < size; ++i)
{
z[i] = x[i] ^ y[i];
}
}
void addTo(long[] x, long[] z)
{
for (int i = 0; i < size; ++i)
{
z[i] ^= x[i];
}
}
void copy(long[] x, long[] z)
{
for (int i = 0; i < size; ++i)
{
z[i] = x[i];
}
}
long[] create()
{
return new long[size];
}
long[] createExt()
{
return new long[sizeExt];
}
void decodeBytes(byte[] bs, long[] z)
{
int partialBits = bits & 63;
Pack.littleEndianToLong(bs, 0, z, 0, size - 1);
byte[] last = new byte[8];
System.arraycopy(bs, (size - 1) << 3, last, 0, (partialBits + 7) >>> 3);
z[size - 1] = Pack.littleEndianToLong(last, 0);
// assert (z[Size - 1] >> partialBits) == 0L;
}
byte[] encodeBitsTransposed(long[] x)
{
byte[] bs = new byte[bits];
bs[0] = (byte)(x[0] & 1L);
for (int i = 1; i < bits; ++i)
{
bs[bits - i] = (byte)((x[i >>> 6] >>> (i & 63)) & 1L);
}
return bs;
}
void encodeBytes(long[] x, byte[] bs)
{
int partialBits = bits & 63;
// assert (x[size - 1] >>> partialBits) == 0L;
Pack.longToLittleEndian(x, 0, size - 1, bs, 0);
byte[] last = new byte[8];
Pack.longToLittleEndian(x[size - 1], last, 0);
System.arraycopy(last, 0, bs, (size - 1) << 3, (partialBits + 7) >>> 3);
}
void inv(long[] a, long[] z)
{
long[] f = create();
long[] g = create();
long[] t = create();
copy(a, f);
copy(a, t);
int rSub2 = bits - 2;
int bits = 32 - Integers.numberOfLeadingZeros(rSub2);
for (int i = 1; i < bits; ++i)
{
squareN(f, 1 << (i - 1), g);
multiply(f, g, f);
if ((rSub2 & (1 << i)) != 0)
{
int n = rSub2 & ((1 << i) - 1);
squareN(f, n, g);
multiply(t, g, t);
}
}
square(t, z);
}
void multiply(long[] x, long[] y, long[] z)
{
long[] tt = createExt();
implMultiplyAcc(x, y, tt);
reduce(tt, z);
}
void reduce(long[] tt, long[] z)
{
int partialBits = bits & 63;
int excessBits = 64 - partialBits;
long partialMask = -1L >>> excessBits;
// long c =
Nat.shiftUpBits64(size, tt, size, excessBits, tt[size - 1], z, 0);
// assert c == 0L;
addTo(tt, z);
z[size - 1] &= partialMask;
}
int getSize()
{
return size;
}
int getSizeExt()
{
return sizeExt;
}
void square(long[] x, long[] z)
{
long[] tt = createExt();
implSquare(x, tt);
reduce(tt, z);
}
void squareN(long[] x, int n, long[] z)
{
// assert n > 0;
/*
* In these polynomial rings, 'squareN' for some 'n' is equivalent to a fixed permutation of the
* coefficients. Calls to 'inv' generate calls to 'squareN' with a predictable sequence of 'n' values.
* For such 'n' above some cutoff value, we precalculate a small constant and then apply the permutation in
* place of explicit squaring for that 'n'.
*/
if (n >= PERMUTATION_CUTOFF)
{
implPermute(x, n, z);
return;
}
long[] tt = createExt();
implSquare(x, tt);
reduce(tt, z);
while (--n > 0)
{
implSquare(z, tt);
reduce(tt, z);
}
}
private static int implModAdd(int m, int x, int y)
{
int t = x + y - m;
return t + ((t >> 31) & m);
}
protected void implMultiplyAcc(long[] x, long[] y, long[] zz)
{
long[] u = new long[16];
// Schoolbook
// for (int i = 0; i < size; ++i)
// {
// long x_i = x[i];
//
// for (int j = 0; j < size; ++j)
// {
// long y_j = y[j];
//
// implMulwAcc(u, x_i, y_j, zz, i + j);
// }
// }
// Arbitrary-degree Karatsuba
for (int i = 0; i < size; ++i)
{
implMulwAcc(u, x[i], y[i], zz, i << 1);
}
long v0 = zz[0], v1 = zz[1];
for (int i = 1; i < size; ++i)
{
v0 ^= zz[i << 1]; zz[i] = v0 ^ v1; v1 ^= zz[(i << 1) + 1];
}
long w = v0 ^ v1;
for (int i = 0; i < size; ++i)
{
zz[size + i] = zz[i] ^ w;
}
int last = size - 1;
for (int zPos = 1; zPos < (last * 2); ++zPos)
{
int hi = Math.min(last, zPos);
int lo = zPos - hi;
while (lo < hi)
{
implMulwAcc(u, x[lo] ^ x[hi], y[lo] ^ y[hi], zz, zPos);
++lo;
--hi;
}
}
}
private void implPermute(long[] x, int n, long[] z)
{
int r = bits;
int pow_1 = ((Integer)halfPowers.get(Integers.valueOf(n))).intValue();
int pow_2 = implModAdd(r, pow_1, pow_1);
int pow_4 = implModAdd(r, pow_2, pow_2);
int pow_8 = implModAdd(r, pow_4, pow_4);
int p0 = r - pow_8;
int p1 = implModAdd(r, p0, pow_1);
int p2 = implModAdd(r, p0, pow_2);
int p3 = implModAdd(r, p1, pow_2);
int p4 = implModAdd(r, p0, pow_4);
int p5 = implModAdd(r, p1, pow_4);
int p6 = implModAdd(r, p2, pow_4);
int p7 = implModAdd(r, p3, pow_4);
for (int i = 0; i < size; ++i)
{
long z_i = 0;
for (int j = 0; j < 64; j += 8)
{
p0 = implModAdd(r, p0, pow_8);
p1 = implModAdd(r, p1, pow_8);
p2 = implModAdd(r, p2, pow_8);
p3 = implModAdd(r, p3, pow_8);
p4 = implModAdd(r, p4, pow_8);
p5 = implModAdd(r, p5, pow_8);
p6 = implModAdd(r, p6, pow_8);
p7 = implModAdd(r, p7, pow_8);
z_i |= ((x[p0 >>> 6] >>> p0) & 1L) << (j + 0);
z_i |= ((x[p1 >>> 6] >>> p1) & 1L) << (j + 1);
z_i |= ((x[p2 >>> 6] >>> p2) & 1L) << (j + 2);
z_i |= ((x[p3 >>> 6] >>> p3) & 1L) << (j + 3);
z_i |= ((x[p4 >>> 6] >>> p4) & 1L) << (j + 4);
z_i |= ((x[p5 >>> 6] >>> p5) & 1L) << (j + 5);
z_i |= ((x[p6 >>> 6] >>> p6) & 1L) << (j + 6);
z_i |= ((x[p7 >>> 6] >>> p7) & 1L) << (j + 7);
}
z[i] = z_i;
}
z[size - 1] &= -1L >>> -r;
}
private static int generateHalfPower(int r, int r32, int n)
{
int p = 1;
int k = n;
while (k >= 32)
{
int y = r32 * p;
long t = (y & 0xFFFFFFFFL) * r;
long u = t + p;
// assert (int)u == 0;
p = (int)(u >>> 32);
k -= 32;
}
if (k > 0)
{
int mk = -1 >>> -k;
int y = (r32 * p) & mk;
long t = (y & 0xFFFFFFFFL) * r;
long u = t + p;
// assert ((int)u & mk) == 0;
p = (int)(u >>> k);
}
return p;
}
private static void generateHalfPowersInv(Map halfPowers, int r)
{
int rSub2 = r - 2;
int bits = 32 - Integers.numberOfLeadingZeros(rSub2);
int r32 = Mod.inverse32(-r);
for (int i = 1; i < bits; ++i)
{
int m = 1 << (i - 1);
if (m >= PERMUTATION_CUTOFF && !halfPowers.containsKey(Integers.valueOf(m)))
{
halfPowers.put(Integers.valueOf(m), Integers.valueOf(generateHalfPower(r, r32, m)));
}
if ((rSub2 & (1 << i)) != 0)
{
int n = rSub2 & ((1 << i) - 1);
if (n >= PERMUTATION_CUTOFF && !halfPowers.containsKey(Integers.valueOf(n)))
{
halfPowers.put(Integers.valueOf(n), Integers.valueOf(generateHalfPower(r, r32, n)));
}
}
}
}
private static void implMulwAcc(long[] u, long x, long y, long[] z, int zOff)
{
// u[0] = 0;
u[1] = y;
for (int i = 2; i < 16; i += 2)
{
u[i ] = u[i >>> 1] << 1;
u[i + 1] = u[i ] ^ y;
}
int j = (int)x;
long g, h = 0, l = u[j & 15]
^ u[(j >>> 4) & 15] << 4;
int k = 56;
do
{
j = (int)(x >>> k);
g = u[j & 15]
^ u[(j >>> 4) & 15] << 4;
l ^= (g << k);
h ^= (g >>> -k);
}
while ((k -= 8) > 0);
for (int p = 0; p < 7; ++p)
{
x = (x & 0xFEFEFEFEFEFEFEFEL) >>> 1;
h ^= x & ((y << p) >> 63);
}
// assert h >>> 63 == 0;
z[zOff ] ^= l;
z[zOff + 1] ^= h;
}
private void implSquare(long[] x, long[] zz)
{
Interleave.expand64To128(x, 0, size, zz, 0);
}
}
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