package org.bouncycastle.math.ec.custom.sec; import java.math.BigInteger; import org.bouncycastle.math.raw.Nat; import org.bouncycastle.math.raw.Nat224; public class SecP224R1Field { private static final long M = 0xFFFFFFFFL; // 2^224 - 2^96 + 1 static final int[] P = new int[]{ 0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; static final int[] PExt = new int[]{ 0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000002, 0x00000000, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; private static final int[] PExtInv = new int[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000001, 0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000001 }; private static final int P6 = 0xFFFFFFFF; private static final int PExt13 = 0xFFFFFFFF; public static void add(int[] x, int[] y, int[] z) { int c = Nat224.add(x, y, z); if (c != 0 || (z[6] == P6 && Nat224.gte(z, P))) { addPInvTo(z); } } public static void addExt(int[] xx, int[] yy, int[] zz) { int c = Nat.add(14, xx, yy, zz); if (c != 0 || (zz[13] == PExt13 && Nat.gte(14, zz, PExt))) { if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0) { Nat.incAt(14, zz, PExtInv.length); } } } public static void addOne(int[] x, int[] z) { int c = Nat.inc(7, x, z); if (c != 0 || (z[6] == P6 && Nat224.gte(z, P))) { addPInvTo(z); } } public static int[] fromBigInteger(BigInteger x) { int[] z = Nat224.fromBigInteger(x); if (z[6] == P6 && Nat224.gte(z, P)) { Nat224.subFrom(P, z); } return z; } public static void half(int[] x, int[] z) { if ((x[0] & 1) == 0) { Nat.shiftDownBit(7, x, 0, z); } else { int c = Nat224.add(x, P, z); Nat.shiftDownBit(7, z, c); } } public static void multiply(int[] x, int[] y, int[] z) { int[] tt = Nat224.createExt(); Nat224.mul(x, y, tt); reduce(tt, z); } public static void multiplyAddToExt(int[] x, int[] y, int[] zz) { int c = Nat224.mulAddTo(x, y, zz); if (c != 0 || (zz[13] == PExt13 && Nat.gte(14, zz, PExt))) { if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0) { Nat.incAt(14, zz, PExtInv.length); } } } public static void negate(int[] x, int[] z) { if (Nat224.isZero(x)) { Nat224.zero(z); } else { Nat224.sub(P, x, z); } } public static void reduce(int[] xx, int[] z) { long xx10 = xx[10] & M, xx11 = xx[11] & M, xx12 = xx[12] & M, xx13 = xx[13] & M; final long n = 1; long t0 = (xx[7] & M) + xx11 - n; long t1 = (xx[8] & M) + xx12; long t2 = (xx[9] & M) + xx13; long cc = 0; cc += (xx[0] & M) - t0; long z0 = cc & M; cc >>= 32; cc += (xx[1] & M) - t1; z[1] = (int)cc; cc >>= 32; cc += (xx[2] & M) - t2; z[2] = (int)cc; cc >>= 32; cc += (xx[3] & M) + t0 - xx10; long z3 = cc & M; cc >>= 32; cc += (xx[4] & M) + t1 - xx11; z[4] = (int)cc; cc >>= 32; cc += (xx[5] & M) + t2 - xx12; z[5] = (int)cc; cc >>= 32; cc += (xx[6] & M) + xx10 - xx13; z[6] = (int)cc; cc >>= 32; cc += n; // assert cc >= 0; z3 += cc; z0 -= cc; z[0] = (int)z0; cc = z0 >> 32; if (cc != 0) { cc += (z[1] & M); z[1] = (int)cc; cc >>= 32; cc += (z[2] & M); z[2] = (int)cc; z3 += cc >> 32; } z[3] = (int)z3; cc = z3 >> 32; // assert cc == 0 || cc == 1; if ((cc != 0 && Nat.incAt(7, z, 4) != 0) || (z[6] == P6 && Nat224.gte(z, P))) { addPInvTo(z); } } public static void reduce32(int x, int[] z) { long cc = 0; if (x != 0) { long xx07 = x & M; cc += (z[0] & M) - xx07; z[0] = (int)cc; cc >>= 32; if (cc != 0) { cc += (z[1] & M); z[1] = (int)cc; cc >>= 32; cc += (z[2] & M); z[2] = (int)cc; cc >>= 32; } cc += (z[3] & M) + xx07; z[3] = (int)cc; cc >>= 32; // assert cc == 0 || cc == 1; } if ((cc != 0 && Nat.incAt(7, z, 4) != 0) || (z[6] == P6 && Nat224.gte(z, P))) { addPInvTo(z); } } public static void square(int[] x, int[] z) { int[] tt = Nat224.createExt(); Nat224.square(x, tt); reduce(tt, z); } public static void squareN(int[] x, int n, int[] z) { // assert n > 0; int[] tt = Nat224.createExt(); Nat224.square(x, tt); reduce(tt, z); while (--n > 0) { Nat224.square(z, tt); reduce(tt, z); } } public static void subtract(int[] x, int[] y, int[] z) { int c = Nat224.sub(x, y, z); if (c != 0) { subPInvFrom(z); } } public static void subtractExt(int[] xx, int[] yy, int[] zz) { int c = Nat.sub(14, xx, yy, zz); if (c != 0) { if (Nat.subFrom(PExtInv.length, PExtInv, zz) != 0) { Nat.decAt(14, zz, PExtInv.length); } } } public static void twice(int[] x, int[] z) { int c = Nat.shiftUpBit(7, x, 0, z); if (c != 0 || (z[6] == P6 && Nat224.gte(z, P))) { addPInvTo(z); } } private static void addPInvTo(int[] z) { long c = (z[0] & M) - 1; z[0] = (int)c; c >>= 32; if (c != 0) { c += (z[1] & M); z[1] = (int)c; c >>= 32; c += (z[2] & M); z[2] = (int)c; c >>= 32; } c += (z[3] & M) + 1; z[3] = (int)c; c >>= 32; if (c != 0) { Nat.incAt(7, z, 4); } } private static void subPInvFrom(int[] z) { long c = (z[0] & M) + 1; z[0] = (int)c; c >>= 32; if (c != 0) { c += (z[1] & M); z[1] = (int)c; c >>= 32; c += (z[2] & M); z[2] = (int)c; c >>= 32; } c += (z[3] & M) - 1; z[3] = (int)c; c >>= 32; if (c != 0) { Nat.decAt(7, z, 4); } } }