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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 1.5 to JDK 1.8.
package org.bouncycastle.math.ec.custom.sec;
import java.math.BigInteger;
import org.bouncycastle.math.raw.Nat;
import org.bouncycastle.math.raw.Nat160;
public class SecP160R2Field
{
// 2^160 - 2^32 - 2^14 - 2^12 - 2^9 - 2^8 - 2^7 - 2^3 - 2^2 - 1
static final int[] P = new int[]{ 0xFFFFAC73, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
static final int[] PExt = new int[]{ 0x1B44BBA9, 0x0000A71A, 0x00000001, 0x00000000, 0x00000000,
0xFFFF58E6, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
private static final int[] PExtInv = new int[]{ 0xE4BB4457, 0xFFFF58E5, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF,
0x0000A719, 0x00000002 };
private static final int P4 = 0xFFFFFFFF;
private static final int PExt9 = 0xFFFFFFFF;
private static final int PInv33 = 0x538D;
public static void add(int[] x, int[] y, int[] z)
{
int c = Nat160.add(x, y, z);
if (c != 0 || (z[4] == P4 && Nat160.gte(z, P)))
{
Nat.add33To(5, PInv33, z);
}
}
public static void addExt(int[] xx, int[] yy, int[] zz)
{
int c = Nat.add(10, xx, yy, zz);
if (c != 0 || (zz[9] == PExt9 && Nat.gte(10, zz, PExt)))
{
if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0)
{
Nat.incAt(10, zz, PExtInv.length);
}
}
}
public static void addOne(int[] x, int[] z)
{
int c = Nat.inc(5, x, z);
if (c != 0 || (z[4] == P4 && Nat160.gte(z, P)))
{
Nat.add33To(5, PInv33, z);
}
}
public static int[] fromBigInteger(BigInteger x)
{
int[] z = Nat160.fromBigInteger(x);
if (z[4] == P4 && Nat160.gte(z, P))
{
Nat160.subFrom(P, z);
}
return z;
}
public static void half(int[] x, int[] z)
{
if ((x[0] & 1) == 0)
{
Nat.shiftDownBit(5, x, 0, z);
}
else
{
int c = Nat160.add(x, P, z);
Nat.shiftDownBit(5, z, c);
}
}
public static void multiply(int[] x, int[] y, int[] z)
{
int[] tt = Nat160.createExt();
Nat160.mul(x, y, tt);
reduce(tt, z);
}
public static void multiplyAddToExt(int[] x, int[] y, int[] zz)
{
int c = Nat160.mulAddTo(x, y, zz);
if (c != 0 || (zz[9] == PExt9 && Nat.gte(10, zz, PExt)))
{
if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0)
{
Nat.incAt(10, zz, PExtInv.length);
}
}
}
public static void negate(int[] x, int[] z)
{
if (Nat160.isZero(x))
{
Nat160.zero(z);
}
else
{
Nat160.sub(P, x, z);
}
}
public static void reduce(int[] xx, int[] z)
{
long cc = Nat160.mul33Add(PInv33, xx, 5, xx, 0, z, 0);
int c = Nat160.mul33DWordAdd(PInv33, cc, z, 0);
// assert c == 0 || c == 1;
if (c != 0 || (z[4] == P4 && Nat160.gte(z, P)))
{
Nat.add33To(5, PInv33, z);
}
}
public static void reduce32(int x, int[] z)
{
if ((x != 0 && Nat160.mul33WordAdd(PInv33, x, z, 0) != 0)
|| (z[4] == P4 && Nat160.gte(z, P)))
{
Nat.add33To(5, PInv33, z);
}
}
public static void square(int[] x, int[] z)
{
int[] tt = Nat160.createExt();
Nat160.square(x, tt);
reduce(tt, z);
}
public static void squareN(int[] x, int n, int[] z)
{
// assert n > 0;
int[] tt = Nat160.createExt();
Nat160.square(x, tt);
reduce(tt, z);
while (--n > 0)
{
Nat160.square(z, tt);
reduce(tt, z);
}
}
public static void subtract(int[] x, int[] y, int[] z)
{
int c = Nat160.sub(x, y, z);
if (c != 0)
{
Nat.sub33From(5, PInv33, z);
}
}
public static void subtractExt(int[] xx, int[] yy, int[] zz)
{
int c = Nat.sub(10, xx, yy, zz);
if (c != 0)
{
if (Nat.subFrom(PExtInv.length, PExtInv, zz) != 0)
{
Nat.decAt(10, zz, PExtInv.length);
}
}
}
public static void twice(int[] x, int[] z)
{
int c = Nat.shiftUpBit(5, x, 0, z);
if (c != 0 || (z[4] == P4 && Nat160.gte(z, P)))
{
Nat.add33To(5, PInv33, z);
}
}
}
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