diff options
Diffstat (limited to 'core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224K1Field.java')
-rw-r--r-- | core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224K1Field.java | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224K1Field.java b/core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224K1Field.java new file mode 100644 index 00000000..0db90e56 --- /dev/null +++ b/core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224K1Field.java @@ -0,0 +1,178 @@ +package org.spongycastle.math.ec.custom.sec; + +import java.math.BigInteger; + +import org.spongycastle.math.raw.Nat; +import org.spongycastle.math.raw.Nat224; + +public class SecP224K1Field +{ + // 2^224 - 2^32 - 2^12 - 2^11 - 2^9 - 2^7 - 2^4 - 2 - 1 + static final int[] P = new int[]{ 0xFFFFE56D, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, + 0xFFFFFFFF }; + static final int[] PExt = new int[]{ 0x02C23069, 0x00003526, 0x00000001, 0x00000000, 0x00000000, + 0x00000000, 0x00000000, 0xFFFFCADA, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; + private static final int[] PExtInv = new int[]{ 0xFD3DCF97, 0xFFFFCAD9, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, + 0xFFFFFFFF, 0xFFFFFFFF, 0x00003525, 0x00000002 }; + private static final int P6 = 0xFFFFFFFF; + private static final int PExt13 = 0xFFFFFFFF; + private static final int PInv33 = 0x1A93; + + 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))) + { + Nat.add33To(7, PInv33, 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))) + { + Nat.add33To(7, PInv33, z); + } + } + + public static int[] fromBigInteger(BigInteger x) + { + int[] z = Nat224.fromBigInteger(x); + if (z[6] == P6 && Nat224.gte(z, P)) + { + Nat.add33To(7, PInv33, 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 cc = Nat224.mul33Add(PInv33, xx, 7, xx, 0, z, 0); + int c = Nat224.mul33DWordAdd(PInv33, cc, z, 0); + + // assert c == 0L || c == 1L; + + if (c != 0 || (z[6] == P6 && Nat224.gte(z, P))) + { + Nat.add33To(7, PInv33, z); + } + } + + public static void reduce32(int x, int[] z) + { + if ((x != 0 && Nat224.mul33WordAdd(PInv33, x, z, 0) != 0) + || (z[6] == P6 && Nat224.gte(z, P))) + { + Nat.add33To(7, PInv33, 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) + { + Nat.sub33From(7, PInv33, 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))) + { + Nat.add33To(7, PInv33, z); + } + } +} |