package org.bouncycastle.math.ec.custom.sec; import java.math.BigInteger; import org.bouncycastle.math.raw.Nat; import org.bouncycastle.math.raw.Nat384; public class SecP384R1Field { private static final long M = 0xFFFFFFFFL; // 2^384 - 2^128 - 2^96 + 2^32 - 1 static final int[] P = new int[]{ 0xFFFFFFFF, 0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; static final int[] PExt = new int[]{ 0x00000001, 0xFFFFFFFE, 0x00000000, 0x00000002, 0x00000000, 0xFFFFFFFE, 0x00000000, 0x00000002, 0x00000001, 0x00000000, 0x00000000, 0x00000000, 0xFFFFFFFE, 0x00000001, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; private static final int[] PExtInv = new int[]{ 0xFFFFFFFF, 0x00000001, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFF, 0x00000001, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000001, 0xFFFFFFFE, 0xFFFFFFFF, 0x00000001, 0x00000002 }; private static final int P11 = 0xFFFFFFFF; private static final int PExt23 = 0xFFFFFFFF; public static void add(int[] x, int[] y, int[] z) { int c = Nat.add(12, x, y, z); if (c != 0 || (z[11] == P11 && Nat.gte(12, z, P))) { addPInvTo(z); } } public static void addExt(int[] xx, int[] yy, int[] zz) { int c = Nat.add(24, xx, yy, zz); if (c != 0 || (zz[23] == PExt23 && Nat.gte(24, zz, PExt))) { if (Nat.addTo(PExtInv.length, PExtInv, zz) != 0) { Nat.incAt(24, zz, PExtInv.length); } } } public static void addOne(int[] x, int[] z) { int c = Nat.inc(12, x, z); if (c != 0 || (z[11] == P11 && Nat.gte(12, z, P))) { addPInvTo(z); } } public static int[] fromBigInteger(BigInteger x) { int[] z = Nat.fromBigInteger(384, x); if (z[11] == P11 && Nat.gte(12, z, P)) { Nat.subFrom(12, P, z); } return z; } public static void half(int[] x, int[] z) { if ((x[0] & 1) == 0) { Nat.shiftDownBit(12, x, 0, z); } else { int c = Nat.add(12, x, P, z); Nat.shiftDownBit(12, z, c); } } public static void multiply(int[] x, int[] y, int[] z) { int[] tt = Nat.create(24); Nat384.mul(x, y, tt); reduce(tt, z); } public static void negate(int[] x, int[] z) { if (Nat.isZero(12, x)) { Nat.zero(12, z); } else { Nat.sub(12, P, x, z); } } public static void reduce(int[] xx, int[] z) { long xx16 = xx[16] & M, xx17 = xx[17] & M, xx18 = xx[18] & M, xx19 = xx[19] & M; long xx20 = xx[20] & M, xx21 = xx[21] & M, xx22 = xx[22] & M, xx23 = xx[23] & M; final long n = 1; long t0 = (xx[12] & M) + xx20 - n; long t1 = (xx[13] & M) + xx22; long t2 = (xx[14] & M) + xx22 + xx23; long t3 = (xx[15] & M) + xx23; long t4 = xx17 + xx21; long t5 = xx21 - xx23; long t6 = xx22 - xx23; long cc = 0; cc += (xx[0] & M) + t0 + t5; z[0] = (int)cc; cc >>= 32; cc += (xx[1] & M) + xx23 - t0 + t1; z[1] = (int)cc; cc >>= 32; cc += (xx[2] & M) - xx21 - t1 + t2; z[2] = (int)cc; cc >>= 32; cc += (xx[3] & M) + t0 - t2 + t3 + t5; z[3] = (int)cc; cc >>= 32; cc += (xx[4] & M) + xx16 + xx21 + t0 + t1 - t3 + t5; z[4] = (int)cc; cc >>= 32; cc += (xx[5] & M) - xx16 + t1 + t2 + t4; z[5] = (int)cc; cc >>= 32; cc += (xx[6] & M) + xx18 - xx17 + t2 + t3; z[6] = (int)cc; cc >>= 32; cc += (xx[7] & M) + xx16 + xx19 - xx18 + t3; z[7] = (int)cc; cc >>= 32; cc += (xx[8] & M) + xx16 + xx17 + xx20 - xx19; z[8] = (int)cc; cc >>= 32; cc += (xx[9] & M) + xx18 - xx20 + t4; z[9] = (int)cc; cc >>= 32; cc += (xx[10] & M) + xx18 + xx19 - t5 + t6; z[10] = (int)cc; cc >>= 32; cc += (xx[11] & M) + xx19 + xx20 - t6; z[11] = (int)cc; cc >>= 32; cc += n; // assert cc >= 0; reduce32((int)cc, z); } public static void reduce32(int x, int[] z) { long cc = 0; if (x != 0) { long xx12 = x & M; cc += (z[0] & M) + xx12; z[0] = (int)cc; cc >>= 32; cc += (z[1] & M) - xx12; z[1] = (int)cc; cc >>= 32; if (cc != 0) { cc += (z[2] & M); z[2] = (int)cc; cc >>= 32; } cc += (z[3] & M) + xx12; z[3] = (int)cc; cc >>= 32; cc += (z[4] & M) + xx12; z[4] = (int)cc; cc >>= 32; // assert cc == 0 || cc == 1; } if ((cc != 0 && Nat.incAt(12, z, 5) != 0) || (z[11] == P11 && Nat.gte(12, z, P))) { addPInvTo(z); } } public static void square(int[] x, int[] z) { int[] tt = Nat.create(24); Nat384.square(x, tt); reduce(tt, z); } public static void squareN(int[] x, int n, int[] z) { // assert n > 0; int[] tt = Nat.create(24); Nat384.square(x, tt); reduce(tt, z); while (--n > 0) { Nat384.square(z, tt); reduce(tt, z); } } public static void subtract(int[] x, int[] y, int[] z) { int c = Nat.sub(12, x, y, z); if (c != 0) { subPInvFrom(z); } } public static void subtractExt(int[] xx, int[] yy, int[] zz) { int c = Nat.sub(24, xx, yy, zz); if (c != 0) { if (Nat.subFrom(PExtInv.length, PExtInv, zz) != 0) { Nat.decAt(24, zz, PExtInv.length); } } } public static void twice(int[] x, int[] z) { int c = Nat.shiftUpBit(12, x, 0, z); if (c != 0 || (z[11] == P11 && Nat.gte(12, z, P))) { addPInvTo(z); } } private static void addPInvTo(int[] z) { long c = (z[0] & M) + 1; z[0] = (int)c; c >>= 32; c += (z[1] & M) - 1; z[1] = (int)c; c >>= 32; if (c != 0) { c += (z[2] & M); z[2] = (int)c; c >>= 32; } c += (z[3] & M) + 1; z[3] = (int)c; c >>= 32; c += (z[4] & M) + 1; z[4] = (int)c; c >>= 32; if (c != 0) { Nat.incAt(12, z, 5); } } private static void subPInvFrom(int[] z) { long c = (z[0] & M) - 1; z[0] = (int)c; c >>= 32; c += (z[1] & M) + 1; z[1] = (int)c; c >>= 32; if (c != 0) { c += (z[2] & M); z[2] = (int)c; c >>= 32; } c += (z[3] & M) - 1; z[3] = (int)c; c >>= 32; c += (z[4] & M) - 1; z[4] = (int)c; c >>= 32; if (c != 0) { Nat.decAt(12, z, 5); } } }